US2124788A - Duplex pumping engine - Google Patents

Description

July 26, v1938. A. LEMAN DUPLEX PUMP ING ENGINE Filed Feb. 9, 1937 3 Sheets-Sheet 1 DFW July 26, 1938. A. LEMAN 2,124,788

DUPLEX PUMPING ENGINE Filed Feb. 9, 1937Y 3 Sheets-Sheet 2- A Ax mlm

Salewa/ly.

July 26, 1938. A. l.. LEMAN DUPLEX'PUMPING ENGINE Filed Feb. 9, 1937 3 Sheets-Sheet 3 Patented July 26, 1938 ansias PATENT FFE-e?.

24.124338 DUPLEX PUMPING ENGINE mesnc assiglnrricleltszr to The National Supply Company, Pittsburgh, Pa., a corporation of Pennsylvania yFebruary l9, 193;?"z

serial No. 124,829

`This invention relates pumpsfand more particularlyto an improvement in steam driven duplex pumps of the type as ordinarily employed in oil `eldlwork for the pumpinguof :mud or `slush, -or any other uidmandf particularly to the valve actuating rnechanismi thereof. I n steam driven duplex pumps las heretQfQre used, ithas ordinarily been `necessarylto` placevA the )steam chest and valves at a considerable height above thek steamcylinders.. even though it.has been recognized that suchs an` arrangementl was inefficient l in that it :requires `steam ports of excessive length Witnthe resultant large condensation vlosses and undue clearance. `Themecessity of positioning thesteam chest and; valves at a sufficient height above the steam cylinders hasarisen because of certain limitations imposed by the construction of the valve actuating mech- Manism.

In such a valve actuating mechanism the. rockfshaft levers which are caused to oscillate. by the piston rodsmust be ofsufcient length .to minimize their angle of oscillation-in order, to ,overcome excessive vertical movement atJ their lower ends. 'Ifhe length of theroclshaft levers has therefore determined the minimum elevation of the rockshafts 'In the customary form of duplex steam pumps mow in use it has been commonpractice to polevers.

sition one rockshaft above the` piane of the Valve operating rods and the other rockshaft below the plane of the operating rods. VIn this conventional construction the minimum elevation of the valve l Lrodsz and hence of the valve, is determined by the length of the shorter of the rockshaft levers.

The principal objectof this invention is to provide a steam driven duplexnpump wherein `there is provided a valve actuating mechanism and whereinV the steam chest andV valves are positioned immediately adjacent the steam `cylinders and which structure is such as to permit of the use of the desired length of the rockshaft Another object of this invention is to provide a steam driven duplex pump in which the steam valves are approximately the same length as the steam cylinders in order that the length o the Vsteam ducts may be `further reduced whereby `the clearance volume is reduced to a minimum.

Another object of this invention is,to provide a steam driven duplex pump in Whichthe rockshaft stand portion of the valve actuating mechanism is enclosed in an oil tight housing to protect the same from slush and other for- Other objects and; advantages of this invention it is believed willbe .apparent Yfrom the. following. detailed description of `a preferred embodiment thereof as illustrated in the accompanyng drawings.

In the drawings: 1

Figure ,l` is a sideelevation of the steam driven duplex pump shown partly intross section .and

.showingtheoutline and position of the improve valve actuating*mechanismsv .Figure 2 is an-end view of the ump shown partlyin cross section. s

FigureI 3 is a sectionalA view ofA the water end of ,-the pump taken substantially on the line 3- -3 of Figure 2t i l ,Figure 4 `is a sectional planviewof the valve actuating mechanism taken substantiallyon the line 4-4 of Figure.U .i

Figure is a sectional View ofgthe valve actuating mechanism taken substantially on the line 5- 5;of FigureA., l -Y Figure 6 is a sectional view ofithevalve actuatinglmechanism taken substantially on the lineG-G of Figure 4.

Figuref? is an end elevation of the valve actuating mechanism partly in cross section taken substantially on the'line 1 -1 of Figure 6. Y

Figure 8l is a fragmental sectionaluview taken substantially on the line 8-8 of Figure-5.

My invention as illustrated in its preferred formin `the laccompanying Vdrawings is applied to asteam driven, duplex pump of the typetcommonly used to circulate slush ormud as used -in the rotary system of Vwell drilling? The entire pumpv is mounted on skids ZB-in order to facili tate transportation and installation in the eld. The principal elements or units of this pump maybe generallyreferred to as the steam end A, `the yWater end B, and the valve actuating mechanismC. .s The steam end A includes cylinders; Ile-having steam pistons 2, a steam chest 3, and valves 4. In this particular structure the valves .4 are the `balanced .type commonly referredtoaspiston valves. Steam ducts 5 communicate betweenthesteamchest and. steam cylinders. 'Ihe steam valves 4 are of novel design in that they are approximately the same length as the steam cylinders I and in that they permit the use of short, straight steam ports or ducts 5 at both ends of the cylinder l. Short steam ducts are very desirable since they reduce condensation loss and clearance and therefore favorably affect the efiiciency of the pump'.

The water end B includes water cylinders 3, water pistons 1, suction passages 8, suction valves 9, and discharge valves I3 and a strainer A spider I2 is provided as a means to adjust the pressure on the packing I3 around the removable liner |4 in order that the uid may not pass from one end of the cylinder 6 to the other outside of the liner I 4. The steam end of the piston rod I5 which operates through the stuffing box I6 is xed at one end to the steam piston 2 and at the other end to the spool or crosshead I1. The water end of the piston rod I5 operates through the stuffing box I8 and is xed at one end to the water piston 1 and at the other end to the same crosshead I1. In this way reciprocating motion imparted to the steam piston 2 is transmitted to the water piston 1.

It is of course understood that this duplex pump has two steam cylinders and two water cylinders Y (see Figure 2). In a general Way the pump may be regarded as of two single pumps acting side by side.

The valve actuating mechanism C is mounted upon the frame of the pump between the steam end A and the water end B and serves to communicate reciprocating motion from the piston rods I5 to the steam valves 4, each valve being operated by the piston rod on the opposite side of the pump.

The valve actuating mechanism C includes a case 2| in which there is journaled rock shafts 22 and 23. Rock shafts 22 and 23 are in the same vertical plane. Rock shaft 22 extends through the case 2| at one side and carries the rocker arm 24 which is operated by the piston rod I5a through the piston rod crossheads |1a and roller 26a to cause the rock shaft 22 to oscillate as the piston rod |5a reciprocates. Similarly rock shaft 23 extends through the case 2| and is caused to oscillate by the rocker arm 25 and the piston rod I5 through the piston rod crosshead I 1 and the roller 26. The parts designated by a numeral with the sufx a in the foregoing correspond to the parts given the same numeral but on the opposite side of the pump.

The rockshaft 22 carries an upwardly extending crank 21 and the rock shaft 23 carries a similar but downwardly extending crank 28. The axes of the pins 29 and 3|! at the outer ends of the cranks 21 and 28 are substantially in the same horizontal plane. The crank 21 is pivotally connected to a link 3| which in turn is pivotally connected to its crosshead 33. Crank 28 is similarly connected to its crosshead 33a through a link 32. The crossheads 33 and 33a are slidably mounted in bearings within the case 2| and are caused to reciprocate by links 3| and 32 respectively. Their reciprocation is communicated to the valve actuating rods 34 which are directly connected to them and lie on their respective axes extended.

A novel and important feature of this arrangement is that it permits the crossheads 33 and 33a. to be positioned at a low elevation with respect to the steam cylinders I Without sacrificing the length of the rocker arms 24 and 25. The length of the steam ducts 5 may be thus kept at a minimum, allowing greater efficiency without causing greater excess of angularity of oscillation and consequent undue vertical movement of the lower ends of the rocker arms 24 and 25.

The case 2| is held securely to the pump frame by means of studs 35 and nuts 36. The case covers 31, 38 and 33 permit access to the interior of the housing or case 2|. The rock shaft cranks, links, and a portion of each crosshead are thus enclosed in a unitary structure and are protected from slush or other abrasive material.

In order to provide for adequate lubrication for my improved valve actuating mechanism, I have provided a novel oiling system wherein the crossheads 33 and 33a adjacent the Water end B act as pump plungers in a simplified form of oil pump, thereby utilizing the reciprocating motion of the crossheads to pump lubricant for the bearing mechanism as well as to operate the valves. In order to accomplish this it is provided that when the crosshead 33a moves away from the Water end B, a suction valve 48 opens and lubricant is drawn up from the reservoir 4| in the bottom of the case 2| through the passage 42 and into the chamber 43. When the crosshead 33a moves toward the water end B, suction valve 43 closes,

discharge valve 44 opens, and the lubricant isV forced up through the tube 45 into the upper reservoir 41. In the same manner the reciprocating motion of the crosshead 33 forces lubricant up through the tube 46 into the upper reservoir 41.

The bearings for rockshaft 23 are lubricated directly from the upper reservoir 41. The crank pins 29 and 3l! receive lubricant from the upper reservoir 41 through the openings 48 and 49. Excess lubricant from the openings 48 and 49 falls into an intermediate reservoir 50 from which the bearings for the lower rock shaft 22 are lubricated. Oil overflows the intermediate reservoir 50 through small openings or canals 5I positioned immediately above each crosshead. A stream of oil is thus directed against each crosshead as it reciprocates. A portion of this oil makes its way through the crosshead supporting bearings 68, furnishing ample lubrication therefor. Oil which reaches the outer end of the bearings 58 is drained into the lower reservoir 4I through ducts 52. Another portion of the oil which falls on the crosshead flows through ducts 89 to lubricate the pivotal connection between the links 3| and 32 and their respective crossheads. Excess oil from the canals 5| falls into the lower reservoir 4| to be recirculated.

Oil is prevented from escaping through the bearings which support the rock shafts by means of suitable oil seals 53, 54. Oil seals 55 are placed near the inner ends of the bearings of the crossheads 33 and 33a to prevent the escape of the oil from the 'case 2| at the points where the crossheads pass through the case 2|. These oil seals retain the lubricant within the case 2| and also act to exclude water, slush or other foreign material from passing into the case 2|.

The rocker arm roller bearings 63 and 63a, are lubricated through passages 51 which extend through the rocker arms 24 and 25 and terminate in fittings 58 through which lubricant is applied under pressure. Passages 51 and 31a'l are provided in the rollers 23 and 26a. to permit lubricant to be forced therethrough to provide proper lubrication between the outer peripheries of the rollers 25 and 25a and the flanges of the crossheads I1 and I'la.

Figure 8 shows a detail of the water manifold 59 which is conveniently located in the lower corner of the case 2|. Water is supplied under pressure-to the manifold'59 through intak'efll and discharges 'from vthe manifold through th'e outlets 6l and Bla. Water `is 'then Adirected against the 'piston rods I5"and"|'5at1iroug`h the pet cocks 52 and 62a.

The purpose of `this flushing of thepistoh rods l5 andl`|15af is to wash off sand :and slush that-may accumulate thereon .and thereby minimize abrasion between the rods l5, l5a Yand "thepacking within the stuffing boxes i8.

'I'he operation of `the pumpem'bodyingmy'invention is: Steam admittedinto ithefsteam cylinder l alternately at one `end and then at the other causes the steam `piston Y"2 to reciprocate. This motion is transmitted directly'tot'he water piston 'l since both pistons are rigidly `co'rii'ietted tothe piston rO'd l5'.V Als illustrated i'hiFiglire 1,

fab

when the water piston l"I moves to 'the `right, fluid is drawn into'the left 'c'hariiber 54 through the suction passage-andat the same time other iiuid is being discharged frointhe right chamber 65 through the discharge valve U -and'thrug'h the 'strainer il. 1During this operation the left suction valve (not shown) and the right discharge valve lll are open and all other water valves are closed. Similarly when water piston 'l moves to the left, fluid is drawn into the right chamber 65 through the right Section valve 9 and at the same time the fluid which has just been drawn into the left chamber 64 is discharged through the left discharge valve I0 and through the strainer Il. Thus the water piston 'l discharges uid during both directions of motion.

Since the pump has two sets of pistons and piston rods working side by side, it is necessary that there be a regulating device controlling the stroking of both sides of the pump. The valve actuating mechanism C serves in this capacity, operating both steam valves which in turn control the movement of the steam pistons. As explained above, the motion of each steam valve is controlled by the piston rod on the opposite side of the pump. Assuming the piston rod I5 illustrated in Figure l to be called the near piston rod, and the piston rod l5a on the other side of the pump to be called the far piston rod, then the cycle of operation of the pump may be described as follows:

I'he near piston rod I5 moves to the right, caus- A, ing the rocker arm 25 to move through its ar'c and move the crosshead 33a on the far side of the pump likewise to the right. Due to the necessary lost motion between the valve actuating rods and their respective steam valves, the steam Y valve on the far side of the pump does not move until the near piston rod l5 is almost at the end of its stroke. The far steam valve then moves to the right, admitting steam into the left end of the far steam cylinder. The far steam rod I5a then moves to the right, moving its rocker arm 24 through its arc and causes the near crosshead 33 to move to the left.

Near the end of the stroke of the far piston rod 85a, the lost motion between the near valve actuating rod 34 and its steam valve 4 is taken up, and steam` valve 4 moves tothe left, admitting steam through intake port 5 at the right end of steam cylinder i,

The near piston rod then moves to the left, exhausting steam on the left of the piston through the left steam port 5e, and moving the rocker arm .25 through its arc, which in turn moves the far crosshead 33a to the left. 'I'he far steam valve moves to the left admitting steam to the right end of the far cylinder. The far pi'stno'd 15a-then r'nov'es'to `the left, exhausting steam'on theleftsi'de of the piston through an exhaust duct.` Rocker arm 24 moves then through?its'aic, causing crosshead 33 to move to theright. Steam valve 4 moves to the right, admitting steam to the left end of the Vcylinder I aiidalldwingsteam on the right side of the steam piston l2 t'o exhaust lthroughthe right exhaust port 5. The `lnear piston rod I5 moves to the right asf'befo're vand the cycle of operation is then repeated. Theoperation as thus described constitutesoiie complete cycle and the cycle repeats asl'ng as steaml is supplied.

The steam which is being exhausted through theexliaust yducts 5e irnpinges upon a fiaring section 1of fthevalve `4 with considerable force and 'tends to jerk the Vvalve 4 and to violently take up" thelostmtionbetween it and its actuating rod 34. To overcome this tendency, baffle rings G3 are mounted upon the steam valves 4 as shown. The bafileings 63 deflect exhaustingsteam from the flaring sections ofthe valve 4 and counteract the frcefatsaid iflaring sections'tending to move the valve `longitudirially.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

I claim:

l. In a steam operated pump, a steam cylinder, a piston mounted therein, a steam manifold positioned adjacent each end of said cylinder, an exhaust chamber positioned between said steam manifolds, inlet passages between said manifolds and cylinder, exhaust passages between said cylinder and said chamber, a valve of substantially the same length as said cylinder and adapted to control the ow of steam to and from said cylinder through said passages, said valve having enlarged end portions slidably supported within a bore formed above said cylinder, means including a lost-motion connection to actuate said valve, and baie means secured to said valve between said enlarged end portions to counteract the reactive force acting against the face of an end portion exposed to the exhaust chamber when steam is exhausted through said exhaust passages into said chamber.

2. In a valve actuating mechanism for steam operated duplex pumps, the combination of a housing, a pair of rockshafts rotatably supported in the housing and each having one end extending therethrough, one of said rockshafts having an upwardly extending crank, and the other having a downwardly extending crank, a pair of parallel crossheads slidably mounted in spaced bearings carried by said housing substantially below the level of either of said rockshafts, a link pivotally connected at one end to each crosshead intermediate its bearings and at the other end to one of said cranks, and means operatively associated with the extending end of each rockshaft to impart oscillatory motion thereto.

3. In a valve operating mechanism for steam operated duplex pumps having a pair of piston rods disposed in horizontal parallelism, the combination of a pair of parallel rockshafts positioned above the plane of said piston rods, the axis of each rockshaft being horizontal and in a common plane perpendicular to the plane of the piston rods, each rockshaft having a downwardly extending lever iixed thereon adapted to be actuated by a piston rod, an upwardly extending crank fixed upon one of said rockshafts and a downwardly extending crank fixed upon the other of said rockshafts, a pair of valve operating crossheads disposed in parallelism with said piston rods and positioned in a horizontal plane substantially below the level of either of said rockshafts, guide means for said crossheads, and a link connecting each crosshead to a corresponding crank.

4. In a valve actuating mechanism for steam driven duplex pumps of the direct acting type, the combination of a supporting case, a pair of horizontal shafts rotatably supported by said case, a pair of valve actuating members slidably supported by said case and positioned in a plane below both of said shafts, separate means operatively associated with each shaft and a corresponding valve actuating member and adapted to impart reciprocating motion to the latter upon oscillatory movement of the former, and acting to give said members opposite directions of travel upon movement of said shafts in the same angular direction.

5. In a valve actuating mechanism for steam driven duplex pumps of the direct acting type having a pair of parallel piston rods, pistons on said rods, a pair of adjacent steam cylinders in which said piston rods are adapted to reciprocate, and a steam valve associated with each cylinder; the combination of a pair of horizontal shafts rotatably supported above the plane defined by said piston rods, separate means operatively associated with each one of said shafts and a corresponding piston rod, and adapted to impart oscillation to the shafts upon reciprocation of the piston rods, a pair of valve actuating members each adapted to actuate one of said steam valves, said members being slidably supported in a plane below both of said shafts and positioned in parallel relation with respect to said piston rods, means operatively associated with each shaft and a corresponding Valve actuating member, and adapted to impart reciprocation to the latter upon oscillation of the former, said members having opposite directions of travel for movement of said shafts in the same angular direction, whereby one of said piston rods is adapted to move the valve for the adjacent steam cylinder in a direction opposite to that of its own movement.

ARTHUR L. LEMAN.

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