US3121027A

US3121027A - Tank washing system

Info

Publication number: US3121027A
Application number: US261027A
Authority: US
Inventors: Thomas R Galanor
Original assignee: Theodore E Ferris and Sons
Current assignee: Theodore E Ferris and Sons
Priority date: 1963-02-26
Filing date: 1963-02-26
Publication date: 1964-02-11
Anticipated expiration: 1981-02-11

Description

Feb. 11, 1964y T. R. GALANOR TANK WASHING SYSTEM 4 Sheets-Sheet 1 Filed Feb. 26, 1963 NAN Feb. 11, 1964 Filed Feb. 26, 1963 l 16S-U '5,9 M156 H4157 Ibi T. R. GALANOR TANK WASHING SYSTEM 4 Sheets-Sheet 2 I INVENTOR Tio/14.5 E GALA/vof? ma/W I fm A Us Feb. 11, 1964 T. R. GALANOR 3,121,027

TANK WASHING SYSTEM Filed Feb. 26, 1963 4 Sheets-Sheet 3 L04 ll 4. 10b 207 V19 LOS 'Lm INVENTOR.

7f3/mns E GALA/YO@ ZM/V A @Nays Feb. 11, 1964 T. R. GALANOR TANK WASHING SYSTEM 4 Sheets-Sheet 4 Filed Feb. 26, 1963 R E V m Uited States Patent n 3,l2l,27 Patented Feb. 1l, 1964 alarm? raNrr wasnnio Sterns/r Thoma R. Galnnor, iiverdale, NX., assigner to ri'heodore is. Ferris d; Sons, New York, N., a partnership lili iietl weh. 25, $63, Ser. No. 261,027

it canas. rei. isa-ie) or superstructures of transport veh-icles or vessels, especially ocean-going marine vessels.

An exemplary system for washing tanks in ooean-going marine vessels intended to transport petroleum liquids in bulk which has been used rfor many years is one in which a nozzle-carrying machine havin-g two axes of rotation of its discharge nozzles at right angles to each other is suspended in a tank or tank bay on a hose through which the liquid is provided under pressure which serves as both the energizing uid for a turbine forming part of the machine whereby the nozzles are driven, and the outlet fluid from the nozzles 4themselves which performs the washing function upon impingement against the interior surfaces of the tank. it is a requirement of this system that any tank being washed or cleaned by it be pumped continuously so that there is no accumulation of washin liquid within it, this liquid being at least somewhat contaminated with tank soil after ini-pincement against the interior surfaces of the tank.

Heated salt water is used customarily as the driving and washing uid in the aforedescribed system of the prior art, and, after use, is discharged overboard. Two general disadvantages or at least inconveniences accrue from this use and discharge or disposal. One is a more rapid consumption, that is, wearing `thin of the steel work of tanks than would be the case were fresh water used. The other is the requirement either that a vessel clean its tanks only at sea and not in harbor to avoid harbor contamination by the discharge overboard of considerable quantities of water containing at least trace amounts of oil and other waste material such as metal scale, or that a special barge be brought alongside the vessel in harbor to receive the contaminated salt water eilluent.

Another requirement of the aforedescribed system which results frequently in some inconvenience in its employment is that when the nozzle-carrying machine w ich it uses is suspended in a tank having a depth such as that typical of the cargo tanks of ocean-going petroleum carriers it must be attended from time to time 'for step-wise lowering within the tank in order that there be complete, substantially full-pressure washing of all of the interior tank surfaces by the streams of water issuing from the machine. Additionally, the aforedescribed systern is not ordinarily well adapted to permit the mixing of any kind of detergent with the water supplied to its characteristic machine.

In contrast to the aforedescribed system of the prior art cited for purposes of outstanding example, and considering the marine vessel tank cleaning problem exemplarily for this contrast and not by way of limitation, the tank washing system of the present invention employs and as one of its objects provides nozzle-equipped standpipes installed permanently within the several tanks or tank bays of a liquid cargo ship rather than a set of spray machines which have to be suspended at various heights within bays, and also moved from bay to bay.

n further contrast `to the aforedescribed system of the prior art and as another of its objects, the tank washing system of the present invention provides for the employment of fresh water rather than salt water with this water being reclaimed after use in prerinse, wash, and final rinse cycles or steps rather than being pumped overboard.

in still further contrast to the aforedescribed system of the prior art and as another of its objects, the tank washing system of the present invention is particularly well adapted and provides specifically for the employment of a water and detergent mixture for washing purposes in at least one of its operating steps or cycles, and obviates the discharge of contaminated wastes.

According lto the present invention, each tank bay standpipe is installed in bearings allowing it to be rotated about a vertical axis. It is provided with at least one and normally a plurality of sets of washing nozzles at various elevations, ythe nozzles being rotatable by jet reaction about horizontal axes, that is, axes transverse to the axis of the standpipe. Each standpi-pe is provided further with either an upper or a lower and normally both an upper and a lower set of driving or rotator nozzles which impose rotation upon the standpipe itself by jet reaction.

Fresh water or a fresh water and detergent mixture is supplied to each standpipe through a line coming from a heater and a pump. The pump takes suction from either a pre-rinse, wash, or final rinse water supply tank depending upon the particular cycle or portion of a cycle in which the system is operating. The tank or tank hay being washed or rinsed is kept drained by means of a return main and circulating line leading alternatively to at least one separator such as a centrifugal separator or a bypass around it, and then to a strainer and the suction side of the aforementioned pump for continuous circulation of liquid. Lines and connect-ions are provided for restoration of fresh water to either the pre-rinse, wash, or nal rinse water supply tank as appropriate upon the conclusion of a particular operating cycle.

The pre-rinse, wash, and final rinse water supply tanks are provided to be charged or replenished as necessary and appropriate from a de-emulsi'lier tank, a detergent tank, and a fresh water storage tank. When in operation, the separators discharge separated waste materials to a contaminated oil tank from which this waste may be discharged further to burners of any suitable kind. Liquid non-burnable materials throughout the whole system may be dumped overboard in substantially clean condition through Ia discharge line on the outlet side of the pump normally used to feed the standpipes.

The nature and substance of this invention as well las its objects and advantages will be more clearly perceived and fully understood by referring to the following description and claims taken in connection with the accompany-ing drawings in which:

PEG. 1 represents a diagrammatic arrangement of the tank washing system of this invention;

FiG. 2 represents a view in side elevation of a nozzlecarrying standpipe rotatably installed in a ships cargo tank according to this invention;

FIG. 3 represents an enlarged perspective view of the upper and lower bearing and rotator nozzle portions, and the central portion of the standpipe of FIG. 2;

PEG. 4 represents an enlarged View in partly sectioned side elevation of the upper and lower bearing and rotator nozzle portions and a small part of the central portion of the standpipe of FIG. 2;

FIG. 5 represents an enlarged view in section and partly broken away taken through the standpipe of FIG. 3 along line 5-5 therein looking in the direction of the arrows;

FIG. 6 represents an enlarged View in section taken through the standpipe of FIG. 3 along line 6 6 therein.

Referring now to the drawings in detail, especially tolv FIG. 1 thereof, two representative ships cargo oil tanksor tank bays are designated 2@ and 21. Within tank 2liy there is a rotatable standpipe 22 which is provided with a plurality of sets of rotatable Washing nozzles 23 at Various elevations, and an upper and lower set of driving nozzles 24 and 25 which impose rotation upon the standpipe itself. A rotatable standpipe 26 similar in all essential respects to standpipe 22 is installed in tank 21. Details of structure and installation of these standpipes are illustrated and described in connection with other figures.

At their upper or inlet ends,

standpipes

22 and 26 are connected respectively through suitable rotatable jointsto

branch feeder lines

27 and 28 respectively coming of of washdown supply main 29. Branch lines 27 and Z8' are provided respectively with stop valves 311 and 31 to allow either or both standpipes to be isolated from the washdown main. Another branch feeder line 32 includ-- ing a stop valve 33 is representative of additional connections made off of main 29 for other washdown require-- ments.

Washdown main originates at heater 34 and is pro vided with a stop valve 35 just outside the heater. Valve 35 is provided in turn with a power operating device 36 which is energized through lines 37. These lines may be either hydraulic, pneumatic, or electrical lines, for example, depending upon the nature of operating device 36. Because of its operating device, stop valve 35 is subject to being controlled remotely. Although not illustrated speciiically, valves throughout the system shown in FG. l may be considered to have operators such as operator 36 where appropriate to allow the whole system to be lined up and employed for general or selective washing of tanks by remote control.

Heater 34 may be a heat exchange or a heat transfer device of any suitable kind such as a shell-and-tube heat exchanger designed to be supplied with steam on its shell side for the heating of liquid material, principally water, on its tube side. Steam is furnished to the heater through line 38, and indication of steam conditions is provided by thermometer 39 and pressure gauge di). In the steam connections to the heater, valve 11 is a temperature regulator valve provided with a stop valve on either side, and valve 42 is a bypass check valve.

On its shell side, heater 34 discharges condensed steam through connections 43 to a drain cooler 44. This cooler may be a heat exchange or heat transfer device of any suitable kind such as a shell-and-tube heat exchanger designed to be supplied with hot condensate drains from heater 34 on its shell side and relatively cool fresh water or a mixture of fresh water and detergent on its tube side. The outlet end of the tube side of drain cooler 44 is connected to the inlet end of the tube side of heater 341 by means of line L which includes a liquid flow indicator 46 having

stop valves

46 and 46 on either side of it. On its shell side, the drain cooler is connected to the ships condensate system by line 47. ln the connecting piping structure, valve 48 is a liquid level regulator valve provided with a stop valve on either side, and valve 49 is a bypass needle valve. On a diesel-driven ship, exhaust gases rather than steam may be used for water heating.

The inlet end of the tube side of drain cooler 44 is connected by branch line 5@ to water line 51 coming from the outlet or discharge side of washdown pump 52 which is driven by any suitable prime mover 53 such as a steam turbine or an electric motor. Branch line 50 contains a stop valve 54. Water line 51 continues in a section 55 past the connection of branch line 511 and ties in to washdown supply main 29 beyond valve 35. Line section 55 contains a stop valve 56, and constitutes a bypass section or line around the drain cooler and heater.

Tanks 57, 55, and 53 are respectively the pre-rinse, wash and iinal rinse water supply tanks. Tank 611 is the fresh water storage tank.

Tanks

61 and 62 are respectively the detergent storage tank and the de-emulsier storage tank. Pump 63 driven by prime mover 6A. is a washdown supplies transfer pump. Two series-connected centrifugal separators are designated 65 and 66. Tank 67 is the contaminated oil or refuse tank, and pump 68 driven by prime mover 69 is a refuse pump.

Line 7) is a cycle circulating line which is connected to the inlet or suction side of washdown pump 52 through stop valves 71, 72. and 73, and duplex strainer 74. Prerinse water supply tank 57 is connected to line 70 between valves 71 and 72 by means of tank outlet line 75 including stop valve 76. Wash and iinal rinse water supply tanks 5S and 59 have outlet lines 77 and 78 and outlet stop valves 79 and Sti respectively, lines 77 and 78 connecting to each other and then to line 75 beyond stop valve 76 to make further connection to cycle circulating line 71).

Storage tank 611 may be supplied or replenished with fresh water through either line 81 coming from deck filling valve S2 or line 83 including stop valve 84 coming from the engineering spaces, for example, from fresh water tanks not shown which are fed from the ships evaporators. Lines 81 and 83 join to form a common line 85 including a stop valve 86 on the inlet side of the fresh water storage tank. Tank 661 has an outlet or suction line S7 which connects to cycle circulating line 70 just on the washdown pump side of stop valve 72. Outlet line 87 itself includes stop valves SS and 89, one near fresh water storage tank e@ and the other near the cycle recirculating line.

Detergent and

de-emulsier storage tanks

61 and 62 have outlet lines 91% and 91 and

outlet stop valves

92 and 93 respectively. Lines 90 and 91 join in a common line 94 connecting to the suction side of washdown supplies transfer pump 63 through inlet stop valve 95. Pump 63 has an outlet or `discharge line 96 including a stop valve 97 serving as an outlet stop or shutoif valve for pump 63. This pump is also provided with a recirculating line 98 including a relief valve 99. Outlet line 96 divides into branches 11119 and 1111 connecting to wash and final rinse p Water supply tanks 53 and 59 respectively through stop valve 111?. in branch 101) and stop valve 1113 in branch 101.

Line 11M is a washdown return main into which Washdown outlet lines 1115 and 1116 from ships cargo tanks 219 and 21 are connected, these two outlet lines including stop valves 1117 and 1113 respectively. Outlet line 11D9 including stop valve 11@ connecting into return main 104 is representative of additional connections made into this main from regions other than tanks 20 and 21 having washdown requirements. Stop valve 111 is included in w-ashdown return main 104 just ahead of the T-ioint of this main with de-emulsifier cycle circulating line 112 from which `leads away a separator suction line 113 connecting to the inlet side of centrifugal separator 65 lthrough stop valve 114.

Separators

65 and 66 are in serially staged array with respect to water llow through them. Water outlet line 115 from separator 65 leads directly to the inlet connection of separator 66, and includes stopy valves 116 and 117 which may be regarded respectively `as Ithe outlet stop valve for separator 65 and the inlet stop valve for separator 66. On their waste sides,

separators

65 and 66 respectively have

outlet lines

118 and 119 including stop valves 12@ and 121.

Lines

118 and 119 join ina common waste -line 122 to enter contaminated oil tank 67 through stop valve 123. Tank 67 has an outlet line 124 leading to the inlet side of refuse pump 68, and including a tank outlet stop valve 125 and a pump inlet stop valve 126. The refuse pump has an outlet line 127 including a stop `valve 12S. Desirably although not necessarily for purposes of the present invention, line 127 leads to burners designed to handle oil mixed with at least traces of solid contaminants and some other liquids such as Water, detergent, and de-emulsiier. Energization of pump 63 to withdraw waste material from tank 67 is effected by level sensing element 12S within the tank.

Separator 66 has a Water or clean product outlet line 129 which may also be designated a tank return line. This line includes two

stop valves

136 and 131 close to the water outlet connection of separator 66, and cycle circulating line 76 is taken off of outlet line 129 between these two valves. Line 70 itself includes a stop valve 132 fairly close to its connection to line 129. Water or other liquid may flow from separator suction line 113 into cycle circulating line 7i? without ever going through the separators by being routed through lbypass or wash cycle return line 133. This line, which includes

stop valves

134 and 135, is taken oit of line 133 just ahead of stop valve 114 and connects into line 70 just ahead of stop valve 132.

A valveless cross-connection line 136 extends between Water outlet line 115 from separator 65 and bypass line 133, connecting into line 115 between valves 116 and 117 and into line 133 between

valves

134 and 135. By means of this line, nearby valves being set appropriately open or shut as will be apparent to those skilled in the art, liquid material owing through separator suction line 113 may be routed through either one of

separators

65 and 66 to the exclusion of the other.

Clean product outlet line 129 extends from separato-r 66 to nal rinse water supply tank 59, and includes a stop valve 137 close to this tank. Shortly ahead of valve 137, :1 branch line 13S is taken olf of line 129, and itself divides into two

branch lines

139 and 166 which are connected to wash and pre-rinse water supply tanks 58 and 57 respectively through

stop valves

141 and 142.

Washdown pump 52 is provided with an outlet stop valve 143 in its discharge line 51. 1t is also provided with a recirculating line 144 including a relief valve 145. Just beyond valve 143 a suitably valved overboard discharge line 146 is taken oif of line 51. De-emulsilier cycle circulating line 112 including a stop valve 147 is taken oli of pump discharge line 51 just lbeyond the overboard connection. Line 112 makes a cross joint in line 51 with a line 1423 including a stop valve 149. Line 148 divides into three branches, 151 and 152, which connect to pre-rinse, Wash, and nal rinse water supply tanks 57, 5S and 59 respectively through

stop valves

153, 154 and 155.

Shown in dashed outline is a lire and emergency wash down pump 156 which is connected in

lines

70 and 51 in parallel with pump 52. Pump 156 is -a regularly installed ships pump which is ordinarily reserved for service on the nre main, but which may be employed in the washdown system, that is, for tank Washing purposes, in an emergency. Washdown pump 52, on the other hand, may be a pump specially installed for the washdown system, or it may be a regularly installed cargo tank stripping pump where such a pump is available.

The tank washing or tank cleaning and gas freeing system of this invention operates in three fundamental steps or cycles as follows: (l) the pre-rinse cycle, (2) the wash cycle, and (3) the nal rinse cycle.

To review the pre-rinse cycle operation of the tank Washing system of the present invention, imagine that all valves shown in FlG. l are closed except

valves

125, 126 and 123, and the valves allowing ow of steam into and condensate out of heater 34 `and drain cooler 44. Imagine further that

tanks

57, 58, 59 and 66 are full of fresh Water and that

tanks

61 and 62 contain working quantities of detergent and de-emulsifier respectively. Tanks 26 and 21 are, of course, empty.

As a rst step in the pre-rinse cycle operation, the following valves, starting rom pre-rinse water supply tank 57, are opened: 76, 72, 73, 143, 54, 46', 46", 35, 56 (partly if at all), 30, 31, 33 (possibly), 107, 108, 169

(if valve 33 is opened), 111, 114, 116, 117, 130, 120, 121, 123, 132, and 71. These valves having been opened, washdown pump 52 and

separators

65 and 66, are started. The pump withdraws fresh water from pre-rinse tank 57 through lines 75 land 7l?, and discharges it through

lines

51 and 52, drain cooler 44, line 45, heater 34, Washdown supply main 29, and

branch feeder lines

27, 23, and 32 to

standpipes

22 and 26 and any points of `consumption connected to branch feeder line 32. Valve 76 is closed :as soon as tank 57 has been substantially emptied by the action of pump 52.

For temperature regulation purposes, some of the water leaving pump 52 may be bypassed around drain cooler 44 and heater 34 through line 55. In any event, pre-rinse Water delivered to the standpipes should have a delivery Itemperature and pressure of about F. and 175 p.s.i.g. Water issuing from upper and lower driving or rotator nozzle sets such as sets 24 and 25 causes the standpipes to spin on their bearings about their vertical axes. Water issuing from intermediately located nozzle sets 23 causes these sets to rotate about axes transverse or horizontal with respect to the standpipes while of course they are turning with the standpipes themselves under the iniluence of reactive forces of steady jets of water discharging from the rotator nozzle sets.

Water discharged from the various nozzle sets on the standpipes impinges on the bulkheads, decks, and overheads of tanks 211 and 21, and in the course of an extended operation every portion of interior surface of the tanks will be struck directly by a Water jet. As the Warm streams of fresh Water impinge upon the tank decks, bulkheads, and overheads they remove gross amounts of liquid (oil) and solid (rust and scale) contaminants from these surfaces. Pre-rinse water and the contaminants which it has dislodged are Withdrawn continuously through

lines

165, 166, 109, 104, and 113 by the suction eect of pump 52 acting back through

separators

66 and 65. Separator 65 eifects an initial separation or cleaning of the withdrawn liquid, and sends fairly clean water to separator 66 through line 115, and contaminants to reyfuse or contaminated oil tank 67 through

lines

118 and 122. Separator 66 performs a final cleaning operation on the liquid material, essentially entirely water, which it receives, and discharges a stream of quite clean Water into

lines

129 and 76, and a small amount of contaminants into tank 67 through

lines

119 and 122. A rising level of contaminants in tank 67 causes pump 68 to be started by sensing element 123 with resultant discharge of at least some contaminant material from the tank through line 241 to burners not shown.

Water tlowing in line 76' is returned to the suction side of pump 52 through strainer 74 through which, of course, has already passed any Water Withdrawn by the pump from pre-rinse water supply tank 57. Pump 52 and

separators

65 and 66 continue to operate to circulate water through

standpipes

22 and 26 and tanks 211 and 21 and to clean this Water after contamination for as long as necessary and desired for the duration of the pre-rinse cycle. Duplex strainer 74 at which at least some solid soil from lines downstream of the separator may be eX- pected to be stopped is shifted and cleaned from time to time in routine fashion during not only the pre-rinse cycle but also the wash and final rinse cycles. After tanks 20 and 21 have been adequately pre-rinsed, valves 54 and 56 are closed to shut ol ow of water to the drain cooler, heater, and standpipes, and

valves

149 and 153 are opened. `Now as pump 52 and

separators

65 and 66 continue to operate, water withdrawn from tan-ks 20 and 21 and the return and circulating lines following these tanks is discharged back to pre-rinse water supply tank 57 through

lines

148 and 159.

After as much of the pre-rinse circulating Water as possible has been restored to tank 57,

separators

65 and 66 are shut down, but pump 52 is kept running. Valves 38 and 89 are now opened to let the Washdown pump draw fresh water from storage tank 6i) through line 87, and discharge it into tank 57 to replenish this tank for any water originally in it that may not have been recovered after pre-rinse circulation. Once tank 57 has been refilled, pump 52 is shut down, and

valves

114, 116, 117, 136, 129, 121, 123, 149, 153, 88, and 89 are closed. The valves remaining open besides those allowing flow of steam into and condensate out of heater 34 and drain cooler i4 are

valves

72, 73, 143, 46', 46", 35, 30, 31, 33, 107, 108, 109, 111, 132, 71, 125, 126, and 128.

Next considering the wash cycle, a suitable mixture of fresh water and detergent is made in wash water supply tank 58. To do this,

valves

92, 95, 97 and 162 are opened, and transfer pump 63 is started and operated as necessary to inject an appropriate quantity of liquid detergent into tank 53 `from tank 61 through

lines

95, 94, 96, and 100. Upon Vcompletion of detergent injection to the extent desired, pump 63 is shut down and

valves

92, 95, 97, and 192 are closed.

For the next step in the wash cycle operation, the following valves, starting from wash water supply tank 58, are opened: 79, 54, 56 (partly if at all), 134, and 135. These valves having been opened, pump 52 is started. The pump withdraws a mixture of fresh water and detergent from wash tank 53 through lines 77, 75, and 70, and circulates it in the same piping path as that previously followed by the plain water in the pre-rinse cycle, except that the circulating mixture flows through bypass line 133 instead of through

separators

65 and 66 and their intermediate piping. The same standpipe delivery condition requirements of about 120 F. and 175 p.s.i.g. obtain. Warm streams of water and detergent mixture issuing from the nozzles of the rotating standpipes impinge upon the bulkheads, decks, and overheads of tanks 2t) and 21 and wash down fine amounts of liquid and solid contaminants from them. Valve 79 is closed as soon as tank 53 has been substantially emptied by the action of pump 52.

Washdown pump 52 is continued in operation to circulate water and detergent mixture material, and the tank soil not stopped at strainer 74, through

standpipes

22 and 26 and tanks 2% and 21 until the tanks are considered to have been thoroughly washed and/or the detergent component of the circulating mixture is considered to have been thoroughly spent, both situations desirably obtaining at just about the same time to effectively terminate the wash cycle. After tanks 26 and 21 have been adequately washed, valves 54 and 56 are closed to shut off flow of mixture material to the drain cooler, heater, and

standpipes, and

valves

149 and 154 are opened. Now as pump 52 continues to operate, soiled water and detergent mixture material withdrawn from tanks 2t) and 21 and the return and circulating lines following these tanks is discharged back to wash water supply tank 58 through lines 14S and 151. After as much of the wash cycle circulating mixture as possible has been restored to tank 58, pump 52 is shut down and

valves

149 and 154 are closed. The valves remaining open besides those allowing flow of steam into and condensate out of heater 34 and drain cooler 44 are

valves

72, 73, 143, 46', 46, 35, 30, 31, 33, 167, 168, 199, 111, 134, 135, 132, 71, 125, 126, and 128.

As a first step in the final rinse cycle operation, the following valves, starting from iinal rinse water supply tank 59, are opened: 311, 54, 56 (partly if at all). These valves having been opened, pump 52 is started. The pump withdraws fresh water from final rinse tank 59 through

lines

73, 75, and 7 il, and circulates it in the same piping path as that previously followed by the water and detergent mixture in the wash cycle, with the same standpipe delivery condition requirements of about 120 F. and 175 p.s.i.g. Warm streams of plain fresh final rinse water issuing from the standpipe nozzles impinge upon the decks, bulkheads, and overheads of tanks 2@ and 21, and rinse down any residual amounts of soil and detergent remaining on their surfaces. Valve 89 is closed as soon as tank 59 has been substantially emptied by the action of pump 52.

After tanks 21B and 21 have been adequately finally rinsed, valves 54 and 56 are closed to shut olf flow of final rinse water to the drain cooler, heater, and standpipes, and

valves

149 and 155 are opened. Now as pump 52 continues to operate, slightly soiled iinal rinse water withdrawn from tanks 21B and 21 and the return and circulating lines following these tanks is discharged back to final rinse water supply tank 59 through lines 14S and 152. After as much of the iinal rinse cycle circulating water as possible has been restored to tank 59, pump 52 is shut down and

valves

149 and 155 are closed.

The pre-rinse, wash, and final rinse cycles having been completed, valves d6', 46, 35, 35, 3l, 33, 197, 16S, 109, 111, 134, 135, 132, and 71 are closed. The valves allowing flow of steam into and condensate out of heater 34 and drain cooler 434 are closed also. The valves remain.- ing open are

valves

72, 73, 143, 125, 126, and 128. Although no operation remains to be carried out on the interior surfaces of cargo tanks 2@ and 21 or any region connected to branch feeder line 33, the liquid material remaining in wash and inal rinse water supply tanks 58 and 59 is subject to further treatment to restore it to a condition of essentially clean water.

The liquid material in wash water supply tank 58 is in an at least somewhat emulsitied condition due to its detergent component, and this condition must be eliminated before the liquid can be cleaned or puriiied by mechanical means such as centrifugal separators and 66. To do this, that is, to break the emulsion in tank 5S,

valves

93, 95, 97, and 162 are opened, and transfer pump 63 is started and operated as necessary to inject an appropriate quantity of liquid de-emulsiiier into tank 5S from tank 62 through

lines

91, 94, 96, and 162. Upon completion of de-emulsifier injection to the extent desired, pump 63 is shut down, and valve 1632 is closed.

For the next step in cleaning the water in tank 53, the following valves are opened: 79, 147, 114, 116, 117, 130, 131, 126, 121, 123, and 141. These valves having been opened, washdown pump 52 and

separators

65 and 66 are started. The pump withdraws water mixed with deter` gent, de-emulsifier, and some liquid contaminants originally on the interior surfaces of tanks 21B and 21 from tank 55 through lines 77, 75, and 713, and discharges it through

lines

51, 112, and 113 to the inlet side of centrifugal separator 65.

Separators

65 and 66 operating in series effect separations or cleaning of the liquid discharged to them from pump 52. Cleaned water leaving separator 66 is drawn back into tank 5S through

lines

129, 138, and 139 by the suction effect of pump 52. Refuse mixture streams of detergent, de-emulsifier, and liquid and possibly some solid tank soil flow from the separators through

lines

113 and 119, and enter refuse tank 67 through line 122. Pump 63 operates to withdraw liquid material from tank 67 through line 124 and discharge it through line 127 to refuse consumption means in accordance with liquid level signals transmitted by sensing element 123.

Pump 52 and

separators

65 and 66 continue to operate to circulate water through tank 55 and to clean this water for as long as necessary and desired; that is, until the body of water in tank 53 at any given time appears to be in substantially clean condition. When this condition is achieved, pump 52 and

separators

65 and 66 are shut down, and valves 79 and 141 are closed.

The liquid material in iinal rinse water supply tank 59 is probably in an at least slightly emulsified condition due to a detergent component. tion, valve 103 is opened, and transfer pump 63 is started and operated as necessary to inject an appropriate quantity of de-emulsifier into tank 59 from tank 62 through

lines

91, 94, 96, and 161. Upon completion of de-emulsier injection, pump 63 is then shut down, and

valves

93, 95, 97, and 103 are closed. Next, valves Si) and 137 To eliminate this condi-A are opened and Washdown pump 52 and

separators

65 and 66 are started. The pump withdraws liquid material from tank 59 through lines 7S, 75, and 7i), and discharges it through

lines

51, 112, and 113 to the inlet side of separator 65. After flowing through separator 65, line 115, and separator 66, water is returned to tank 59 through line 129.

Pump 52 and

separators

65 and 66 continue to operate to circulate water through final rinse water supply/tank 59 and reject liquid refuse to contaminated oil tank 67 for as long as necessary and desired; that is, until the body of water in tank 59 at any given time appears to be in substantially clean condition. When this condition is achieved,

separators

65 and 66 are shut down, and valves 8i), 72, 1e7, 114, 116, 117, 131D, 131, 137, 12d, 121, and 123 are closed. The valves remaining open are

valves

73, 143, 125, 126, and 123, and washdown pump 52 is continued in operation.

Some of the water originally in tanks S and 59 may not have been recovered in them after the wash and iinal rinse cycles and the water cleaning operations just described, With the result that these tanks should be replenished or topped oil with fresh Water from storage tank 63. Accordinvly, valves S8, S9, 149, and 154 are opened and the still-operating pump 52 draws water from tank dil through

lines

87 and 7@ and discharges it into tank 58 through lines 143 and 151. Once tank 5@ has been relled, valve 154 is closed and valve 155 is opened. Pump 52 now discharges water from tank 65B into tank 59 through lines 14S and 152. Once tank 59 has been refilled, pump 52 is shut down, and

valves

88, 89, 73, 1413, 149, and 155 are closed.

Valves

175, 126, and 1233 may be closed also. The body of fresh water in storage tank 69 will have become somewhat depleted in the course of replenishing the water supply in tanks 57, 58, and 59, and should be restored by the admission oi' fresh water to tank 643 through either line 81 or line 35.

in the course of the description so far, no mention has been made of line 14@ leading into pre-rinse water supply tank 57 and valve 142 in this line other than to identify them. This line and valve, although not subject to great use, are desirably installed to allow circulation of water through tank 57 without this water having to be sent through

standpipes

22 and 25 and cargo tanks 2t? and 21.

From time to time it may be desirable to pump the water in tanks 57, 58, and 59 overboard either to obtain access to the interior of these tanks for work or inspection, or to simply lighten the ship of the weight or" water which is associated with them when they are full. To effect this emptying, valves 157 and 153 in overboard discharge line 146 are opened, and so are valves 76, 79, Si?, 72, 73, and 143, and pump S2 is started. The pump withdraws water from the pre-rinse, wash, and iinal rinse water supply tanks, and discharges it overboard through line 146.

The detergent solution or detergent and fresh water mixture as made up in Wash water supply tank 58 is contemplated to be of suiicient strength at the beginning to wash all of the ships tanks in at least one program of washing so that there will not have to be any addition of detergent during the program, or, at most, only enough to replenish or make good the loss associated with washing liquid left in the various tanks or tank bays if Washing is done by groups of tanks or tank bays.

It is within the contemplation of the present invention that wash and iinal rinse water supply tanks 5S and 59 each be divided into two parts. This arrangement, requiring the use of emergency pump 155 and some additional piping and valves, would allow a portion of the washing solution and a portion of the nal rinse water to be cleaned while another portion of each was working.

The starting date and time and the length of each cycle for the cleaning of each tank and an indication of unspent detergent should be logged in by a data logger. A sensing l@ element for indication of unspent. detergent can be installed in wash water supply tank 58.

Referring next to FIGS. `2 and 3, a typical tank vessel or oil tanker of which the structure includes main deck plating 159, bottom plating 166, upper longitudinals `161 and 162,

bottom longitudinals

163 and 164,

deck stieners

165, 166, and 167, and bottom stitfeners 168, 169, and 17o has a tank bay 171 defined in it within which there is installed a typical standpipe 172 according to the present invention, this standpipe being similar to

standpipes

22 and 26 already described generally as components of the tank washing system shown in FIG. 1.

Standpipe 172 comprises pipe sections 173, |174, 175, 17o, 177, and 178 joined by bolts at gasketed mating yilanges. The pipe section assembly is surmounted by upper bearing'assembly 179, and rests upon lower bearing assembly 1181i. Lower bearing assembly 1S@ and indeed the whole assembly of standpipe 172 is supported and provided with bottom alignment on and by foundation elements 181, 182., and 183 which tie in to

bottom longitudinals

163 and 164 and bottom stiener 169. A flanged connection is made to upper bearing assembly 179 `on its upper end by pipe elbow '184 at the outlet end of liquid supply pipe or branch line 185. Top alignment of the standpipe assembly is provided by bracket, elements `186 and 137 which tie in to

upper longitudinals

161 and 162 and pipe elbow 184. Bracket element 187 is attached to bracket element 186 in a slip joint so that movement of deck plating 159 and bottom plating 166 due to working of the ship in a sea and lengthening and shortening of standpipe l17.2 due to temperature changes can be accommodated without placing undue columnar stress upon the standpipe.

Centrally standpipe `172 is aligned laterally by bracket 13S and strap 1&9. Bracket 138 extends between and is supported at its ends 'by transverse web frames 19t) and 191 shown in FG. 4. At about its mid-length, the bracket is formed with a half-round depression or offset to receive pipe section 175, and strap 189 bolted to bracket 18S is formed similarly. The half-round regions of the bracket and strap, therefore, together assume the nature of a sleeve bearing in which the standpipe may be rotated.

Pipe section 173 which is rotatably fitted for part of its length within upper bearing assembly 179 carries

rotator nozzle assemblies

192 and 193. Similarly, pipe section 178 carries

rotator nozzle assemblies

194 and 195. The four rotator nozzle yassemablies are all so oriented with respect to the assembled standpipe that the reactive forces or" liquid jets issuing from them are additive to produce a moment on the standpipe tending to rotate it about a vertical axis. At water supply pressures of about p.s.i.g. it is contemplated that standpipe 172 will turn -at about 35 r.p.m. under the inlluence of the rotator nozzles. The jet streams of plain water and water and detergent mixture discharged from these nozzles or nozzle assemblies may have some eifect to pre-rinse, Wash, and nally rinse some of the interior surfaces of tank bay 171 as well as to provide rotation of the standpipe. In practice, however, other nozzles to be described are relied upon primarily to achieve washing and rinsing eiects.

Washing nozzle sets or

assemblies

196, 197, 198, i199, 25119, 2611, 2112, and 2193 are carried in pairs by

pipe sections

174, 175, 176, and 177. Each washing nozzle assembly is independently rotatable with respect to the pipe section on which it is mounted, and each one has two oppo-sitely aimed nozzle outlet openings which are linearly ofset on opposite sides of the assemblys pivot axis, so that the reactive forces of liquid jets issuing lfrom the assembly are additive to produce a moment upon it tending to rotate it about a horizontal axis normal t-o the standpipe. At water supply pressures of about 175 p.s.i.g. it is contemplated that the washing nozzle assemblies will turn at about 35 r.p.m. with respect to the pipe sections on which they are mounted. Actually, of course, the motion of the nozzle elements of any washing nozzle assembly will be a compound motion consisting of the assemblys rotary motion about a horizontal axis and the standpipes rotation about a vertical axis. Such compound motion insures that in the course of a reasonably extended pre-rinse, wash, or iinal rinse cycle operation all of the interior surfaces of tank bay 171 will be struck by jets of fresh Water or water and detergent mixture issuing from the washing nozzle assemblies.

Referring next to FlGS. 4 and 5, and considering upper bearing assembly 179 particularly, 204 is a bearing hous ing to which the iiange of pipe elbow 184 makes bolted attachment across gasket 2115, and which is open at its upper end in alignment with the pipe elbow bore; 296 is an O-ring seal between housing 2134 and the slightly enlarged upper end of pipe section 173 which has a turning t within a shoulder in the housing; 2117 and 263 are ball bearing sets having their inner races tted on pipe section 173 and their outer races iitted within housing 264; 299 is a split retaining ring aiiixed in a groove to pipe section 173; 21) is a cover plate bolted to housing 204 across gasket 211 and through which pipe section 173 passes with a turning iit, and 212 is an O-ring seal between cover plate 210 and pipe section 173.

Now considering particularly lower bearing assembly 180 in FIG. 4, 213 is a bearing housing to which the flange on the upper end of foundation element 183 makes bolted attachment across gasket 214; 215 and 216 are ball bearing sets having their inner races iitted on the slightly enlarged lower end of pipe section 17S and their outer races tted within housing 213; 217 is a split retaining ring afxed in a groove to pipe section 173; 21S is a cover plate bolted to housing 213 across gasket 219 and through which pipe section 17S passes with a turning iit, and 220 is an O-ring seal between cover plate 218 and pipe section 17S.

Fresh water or a water and detergent mixture pumped into standpipe 172 through branch line 185 and pipe elbow 184- passes down through and into upper bearing assembly housing 204 and

pipe sections

173, 174, 175, 176, 177, and 178 to transverse baffle or partition 221 in the last section, and outwardly from these sections through the several nozzle assemblies which are in uid ow connection with them. Details `of the connections of

rotator nozzle assemblies

192 and 193 to pipe section 173 and

assemblies

194 and 195 to pipe section 17S are shown in FIGS. 4 and 5, considered in association with FlG. 3. In numerical order the rotator nozzle assemblies comprise

curved conduit portions

222, 223, 224, 225 welded around opposite, appropriately vertically located lateral openings in

pipe sections

173 and 173.

Rotator nozzle assemblies

192, 193, 194, and 195 further comprise

nozzle elements

226, 227, 22S, and 229 respectively which are in threaded engagement with the curved conduit portions of the assemblies as shown particularly in FIG. wherein also the reactive rotation of the standpipe is indicated.

Referring finally to FIGS. 6 and 7,

washing nozzle assemblies

198 and 199 which may be considered typical of all of the washing nozzle assemblies respectively comprise

Tashaped spinner members

230 and 231 on the ends of the internally vaned arms or bar portions of which there are respectively

nozzle elements

232 and 233, and 234 and 235. Each nozzle element is in threaded engagement with the spinner member with which it is associated. The stern portions of spinner members 2319 and 231 extend into and are rotatably retained within washing

nozzle bearing assemblies

236 and 237 respectively, these assemblies being retained in place on pipe section 175 and constructed as will be described.

Two

straight conduit portions

238 and 239 are welded around opposite, appropriately vertically located openings in pipe section 175, and have flanges at their outer ends. At these flanges they make bolted connections across gaskets such as gasket 24@ to

housings

241 and 242 of washing

nozzle bearings assemblies

236 and 237. These housings are open at their inner ends in alignment with the bores of conduit portions 23S and 239.

Particularly considering bearing assembly 237, 243 is an O-ring seal between housing 242 and the inner end of the stem portion of spinner member 231 which has a turning iit within a shoulder in the housing; 244 and 245 are ball bearing sets having their inner races fitted on the stem portion of spinner member 231 and their outer races iitted within housing 242; 246 is a split retaining ring affixed in a groove to the spinner member stem portion, and 247 is a friction ring surrounding retaining ring 246; 248 is a friction ring fitted within the bearing housing against which ring 247 rubs to limit the speed of rotation of nozzle assembly 199; 249 is a cover plate bolted to housing 242 across gasket 254B and through which the spinner member stem portion passes with a turning iit, and 251 is an O-ring seal between cover plate 249 and the stem portion of the spinner member of washing nozzle assembly 199.

Water or water and detergent mixture flows outwardly from pipe section through conduit portions 23S and 239, through bearing

housings

241 and 242, through the stem and bar portions of

spinner members

230 and 231, and iinally out of

nozzle elements

232, 233, 234, and 235 and reactively imparts rotation to the washing nozzle assemblies as is shown, for example, in the case of assembly 199 in FIG. 7. In place of friction rings 248 and 247, it is contemplated that an internally toothed ring gear may be installed within bearing housing 242 and a meshing pinion mounted rotatably on the stem portion of spinner member 231 of washing nozzle assembly 199 as speed limiting means. Similar means could, of course, be used on other washing nozzle assemblies as well.

Although this invention has been described with some degree of particularity, it is to be understood that resort may be had to at least some changes in the details of construction of its illustrated apparatus embodiments without departing from the spirit and scope of the invention. It is to be understood especially that this invention is not limited to the washing `of tanks aboard ships nor even to the washing of tanks forming parts of the structures or superstructures of bulk liquid transporters generally such as, for example, highway tank trucks and railway tank cars in addition to water-borne tankers. Specifically it is to be understood that the present invention is well adapted for the washing of permanently installed, land based tanks with the inventive equipment itself as generally illustrated diagrammatically in FIG. l, including the standpipe or standpipes, being of a portable nature.

The present invention is especially valuable, however, as a system for washing the cargo liquid tanks of a marine bulk transporter of liquids, particularly when used in connection with a suitable gas freeing system to obtain certification that the tanks are both clean and gas free. Such certiiication is important because it must be obtained before any cargo liquid which is more highly refined than a previously carried cargo liquid can be put into` the tanks, or any repair work done in the tanks. Obtaining of this certification is expensive and time consuming when traditional methods of tank washing or cleaning are ernployed, since each tank must be opened and inspected visually for cleanliness at the end of some preselected period of treatment according to the initially described system of the prior art, for example. A positive indication of when the tanks are clean is inherently available through the use of the system of the present invention because of the systems amenability to data logging, continuous examination of the water circulated in the various operating cycles, and determination of unspent detergent.

4it is intended to secure protection by Letters Patent of this invention in all its aspects as the same are set forth in the appended claims to the broadest extent that the prior art allows.

What is claimed is:

1. A system for washing the interior surfaces of tanks, said system comprising (l) at least one nozzle-carrying standpipe instalied within a rst tank to be washed, (2)

second, third, and fourth tanks located outside said first tank, said second tank being adapted to contain a liquid pre-rinsing material, said third tank lbeing adapted to contain a liquid washing material, and said fourth tank being adapted to contain a liquid final rinsing material, (3) conduit means including pumping means connecting said second, third, and fourth tanks with said standpipe in a manner permitting liquid to be withdrawn selectively from said second, third, or fourth tank, and discharged to said standpipe for further discharge from the nozzles thereon into said first tank against the interior surfaces thereof, (4) conduit means connecting said rst tank with said pumping means to allow circulation of liquid material from said first tank back to said pumping means without said material passing through said second, third, or fourth tank, and conduit means connecting the discharge side of said pumping means with said second, third and fourth tanks to allow restoration of circulating liquid material selectively to said second, third or fourth tank.

2. A system for washing the interior surfaces of tanks according to claim l in which said conduit means connecting said first tank with the suction side of said pumping means includes (i) separating means whereby liquid material circulated back to said pumping means may have tank soil removed from it, and (ii) bypass means around said separating means, and `which further comprises (6) conduit means connecting the discharge side of said pumping means directly with the inlet side of said separating means, and (7) conduit means connecting the clean liquid material outlet side of said separating means with said third and fourth tanks, by which last two designated conduit means liquid material may be circulated selectively through said third or fourth tank and said separating means without passing through said standpipe and first tank.

3. A system for washing the interior surfaces of tanks according to claim 2 which further comprises (8) fifth and sixth tanks located outside said first tank, said fifth tank being adapted to contain a liquid detergent material, and said sixth tank being adapted to contain a liquid deemulsier material, and (9) conduit means including pumping means connecting said fth and sixth tanks with said third and fourth tanks in a manner permitting liquid material to be alternatively withdrawn from said fifth tank and discharged into said third tank and withdrawn from said sixth tank and discharged selectively into said third or fourth tank.

4. A system for Washing the interior surfaces of tanks according to claim 3 -which further comprises (l0) a seventh tank located outside said first tank, and adapted to contain replenishment liquid material for said second, third, and fourth tanks, and (l1) conduit means connecting said seventh tank with the inlet side of said pumping means in said conduit means connecting said second, third, and fourth tanks with said standpipe.

5. A method for washing the interior surfaces of tanks, said method comprising the steps of (l) in a prerinse cycle, directing jets of water against the interior surfaces of a tank to be washed, thereby removing gross amounts of said from these surfaces; (2) continuously withdrawing pre-rinse water mixed with soil from said tank; (3) continuously passing the withdrawn mixture of pre-rinse water and tank soil through mechanical separating means to generate a stream of clean Water and a stream of Waste liquid material; (4) circulating this clean water as jets of water directed against the interior Surfaces of said tank and thereafter withdrawn from the tank and mechanically cleaned `for the duration of said pre-rinse cycle; (5) removing this water from circulation in clean condition and conserving the same; (6) in a -wash cycle, directing jets of water and detergent mixture against the interior surfaces of said tank, thereby removing ne amounts of soil from these surfaces; (7) continuously withdrawing wash water, detergent, and fine soil mixture from said tank; (8) circulating this mixture as jets of liquid material directed against the interior surfaces of said tank for the duration of said wash cycle; (9) removing this liquid material from circulation and conserving the same in somewhat emulsified condition; (l0) in a final rinse cycle, directing jets of water against the interior surfaces of said tank, thereby removing residual amounts of detergent from these surfaces; (l1) continuously withdrawing final rinse water mixed with residual detergent from said tank; (12) circulating this mixture as jets of liquid material directed against the interior surfaces of said tank for the duration of said final rinse cycle; (13) removing this liquid material from circulation and conserving the same in slightly emulsified condition; (14) chemically breaking the emulsion in the liquid material conserved after said wash cycle; (15) circulating this liquid material as de-emulsified through said mechanical separating means to generate a stream of clean water and a stream of waste liquid material, and conserving the clean water so generated; (16) chemically breaking the emulsion in the liquid material conserved after said final rinse cycle, and 17) circulating this liquid material as (le-emulsified through said mechanical separating means to generate a stream of clean water and a stream of -waste liquid material, and conserving the clean water so generated.

6. A method for washing the interior surfaces of tanks according to claim 5 in which the water used in said pre-rinse, wash, and final rinse cycles is fresh water.

7. A method for washing the interior surfaces of tanks according to claim 5 in which the water and water and detergent mixture jetted against the interior surfaces of said tank in said pre-rinse, wash, and final rinse cycles have a temperature of about F.

8. A method for washing the interior surfaces of tanks according to claim 5 in which the water and detergent mixture jetted against the interior surfaces of said tank in said pre-rinse, wash, and final rinse cycles have a pressure of about p.s.i.g.

9. A method for Washing the interior surfaces of tanks according to claim 5 in which the materials of said streams of waste liquid materials generated in steps (3), (15), and (17) are of a burnable nature.

l0. A method for washing the interior surfaces of tanks according to claim 9 in which said streams of waste liquid materials are directed toward burner means.

l1. A system for washing the interior surfaces of tanks, said system comprising (l) at least one nozzlecarrying standpipe installed within a first tank to be washed, said standpipe being rotatable about its own longitudinal axis and at least some of the nozzles carried by said standpipe being rotatable about axes normal to both their own discharge axes and the longitudinal axis of said standpipe, (2) a second tank located outside said first tank, said second tank being adapted to contain liquid material, (3) conduit means including pumping means and liquid heating means on the discharge side of said pumping means connecting said second tank with said standpipe in a manner permitting liquid material to be withdrawn from said second tank and discharged to said standpipe for further discharge from the nozzles thereon into said first tank against the interior surfaces thereof, (4) conduit means connecting said first tank with the suction side of said pumping means to allow circulation of liquid material from said first tank back to said pumping means without said material passing through said second tank, this conduit means including separating means whereby liquid material circulated back to said pumping means may have tank soil removed from it with the soil material outlet side of the separating means being in iiuid flow connection with burner means, and (5) conduit means connecting the discharge side of said pumping means with said second tank to allow restoration of circulating liquid material to said second tank.

References Cited in the file of this patent UNITED STATES PATENTS 1,624,865 Freel Apr. 12, 1927 1,693,885 Butterworth Dec. 4, 1928 1,722,211 Guardino July 23, 1929 2,092,321 McFadden Sept. 7, 1937 16 Paulson July 12, 1938 Koertge June 10, 1947 Vawter Aug. 19, 1947 Lester Feb. 21, 1950 Borzell Aug. 28, 1951 Grant Sept. 26, 1961 Kearney July 24, 1962 UNITED STATES PATENT oEEICE CERTIFTCATE 0F CGRECTTN Patent Noo 3121O27 February 11 1964 Thomas R Galanor 1t is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as Corrected below.

Column 3 line 17i for "figures" read Figures column 10, 1ihe 4L for "assemlablies" read assemblies column 13, line 611 for "saidf read e soil column 14,I lines 36 and 37Z for "water and detergent" read water and water and detergent --Q Signed and sealed this 30th day of June 19641o SEAL) ttest:

RNEST W. SWIDER EDWARD J BRENNER :testing Officer Commissioner of Patents

Claims

5. A METHOD FOR WASHING THE INTERIOR SURFACES OF TANKS, SAID METHOD COMRPISING THE STEPS OF (1) IN A PRERINSE CYCLE, DIRECTING JETS OF WATER AGAINST THE INTERIOR SURFACES OF A TANK TO BE WASHED, THEREBY REMOVING GROSS AMOUNTS OF SAID FROM THESE SURFACES; (2) CONTINUOUSLY WITHDRAWING PRE-RINSE WATER MIXED WITH SOIL FROM SAID TANK; (3) CONTINUOUSLY PASSING THE WITHDRAWN MIXTURE OF PRE-RINSE WATER AND TANK SOIL THROUGH MECHANICAL SEPARATING MEANS TO GENERATE A STREAM OF CLEAN WATER AND A STREAM OF WASTE LIQUID MATERIAL; (4) CIRCULATING THIS CLEAN WATER AS JETS OF WATER DIRECTED AGAINST THE INTERIOR SURFACES OF SAID TANK AND THEREAFTER WITHDRAWN FROM THE TANK AND MECHANICALLY CLEANED FOR THE DURATION OF SAID PRE-RINSE CYCLE; (5) REMOVING THIS WATER FROM CIRCULATION IN CLEAN CONDITION AND CONSERVING THE SAME; (6) IN A WASH CYCLE, DIRECTING JETS OF WATER AND DETERGENT MIXTURE AGAINST THE INTERIOR SURFACES OF SAID TANK, THEREBY REMOVING FINE AMOUNTS OF SOIL FROM THESE SURFACES; (7) CONTINUOUSLY WITHDRAWING WASH WATER, DETERGENT, AND FINE SOIL MIXTURE FROM SAID TANK; (8) CIRCULATING THIS MIXTURE AS JETS OF LIQUID MATERIAL DIRECTED AGAINST THE INTERIOR SURFACES OF SAID TANK FOR THE DURATION OF SAID WASH CYCLE; (9) REMOVING THIS LIQUID MATERIAL FROM CIRCULATION AND CONSERVING THE SAME IN SOMEWHAT EMULSIFIED CONDITION; (10) IN A FINAL RINSE CYCLE, DIRECTING JETS OF WATER AGAINST THE INTERIOR SURFACES OF SAID TANK, THEREBY REMOVING RESIDUAL AMOUNTS OF DETERGENT FROM THESE SURFACES; (11) CONTINUOUSLY WITHDRAWING FINAL RINSE WATER MIXED WITH RESIDUAL DETERGENT FROM SAID TANK; (12) CIRCULATING THIS MIXTURE AS JETS OF LIQUID MATERIAL DIRECTED AGAINST THE INTERIOR SURFACES OF SAID TANK FOR THE DURATION OF SAID FINAL RINSE CYCLE, (13) REMOVING THIS LIQUID MATERIAL FROM CIRCULATION AND CONSERVING THE SAME IN SLIGHTLY EMULSIFIED CONDITIION; (14) CHEMICALLY BREAKING THE EMULSION IN THE LIQUID MATERIAL CONSEVED AFTER SAID WASH CYCLE; (15) CIRCULATING THIS LIQUID MATERIAL AS DE-EMULSIFIED THROUGH SAID MECHANICAL SEPARATING MEANS TO GENERATE A STREAM OF CLEAN WATER AND A STREAM OF WASTE LIQUID MATERIAL, AND CONSERVING THE CLEAN WATER SO GENERATED; (16) CHEMICALLY BREAKING THE EMULSION IN THE LIQUID MATERIAL CONSERVED AFTER SAID FINAL RINSE CYCLE, AND (17) CIRCULATING THIS LIQUID MATERIAL AS DE-EMULSIFIED THROUGH SAID MECHANICAL SEPARATING MEANS TO GENERATE A STREAM OF CLEAN WATER AND A STREAM OF WASTE LIQUID MATERIAL, AND CONSERVING THE CLEAN WATER SO GENERATED.