US3421665A - Closure for container-lining membrane port - Google Patents

Description

3,421,665 CLOSURE FOR CONTAINER-LINING MEMBRANE PORT Filed Oct. 30.- 1967 Jan. 14, 1969 H. N. K. PATON Sheet I of 5 1N VENT OR. HAM/t ro/v lyiu mva PATDN xlrromvm Jan. 14, 1969 H. N; K; PATON CLOSURE FOR CONTAINER-LINING M Filed Oct. 30. 1967 EMBRANE PORT Sheet 2 INVENTOR. HAN/L700 lYEfl. K1116 PATON ATTORNEY Jan. 14, 1969 H. N. K. PATON CLOSURE FOR CONTAINER-LINING MEMBRANE PORT Sheet Filed Oct. 30. 1967 '1",I"Illlrlllllplllllltllllll IN VEN'TOR.

14 TTOR/YE Y lllllllllllllll '0 lllilrlalltllllll Jan. 14, 1969 H. N. K. PATON 3,421,665

I CLOSURE FOR CONTAINER-LIN'ING MEMBRANE PORT Filed Oct. 30. 1967 Sheet 4 01'5 ATTORNEY.

1969 H. N. K. PAT Oh I 3,

CLOSURE FOR CONTAINER-LINI NG MEMBRANE PORT Filed on. 30. 1967 Sheet 5 of 5 ,4 TTORNEY United States Patent m 3,421,665 CLOSURE FOR CONTAINER-LINING MEMBRANE PORT Hamilton Neil King Paton, Bellevue, Wash., assignor to Dynabulk Corporation, Bellevue, Wash, a corporation of Washington Continuation-impart of applications Ser. No. 307,447,

Sept. 9, 1963, and Ser. No. 408,467, Oct. 30, 1964. This application Oct. 30, 1967, Ser. No. 679,146 U.S. Cl. 222--386.5 18 Claims Int. Cl. B67d /42; B67d 5/64 ABSTRACT OF THE DISCLOSURE A port through a membrane which lines the interior of a container is closed by a rigid cap which may be circular, or such port may have an elongated flexible neck that can be gathered and tied, or such neck can have a slit in its end closable by a separable fastener. Such neck is long enough to extend upward through the coaming of a filler port and be folded over it. The end of the neck can be square so that opposite sides can be pressed into adjacent relationship to be closed by a linear separable fastener or the end of neck can be hemispherical with the separable fastener extending along a great semicircle when closed. Locking mechanism for the separable fastener can be attached to an anchor chain so that the neck can be disconnected from the anchor chain only when the separable fastener is closed. Such latching mechanism includes a plug attached to the separable fastener slider and a plug attached to the anchor chain end insertable, respectively, in crossing bores of a latch block so that one plug is released for withdrawal from its bore only when the other plug is inserted in its bore.

This application is a continuation-in-part of my previous patent application Ser. No. 307,447, filed Sept. 9,

the material in the container. Such membrane can be pressed against discrete particle material in the container beneath it for the purpose of packing the particles of the material together to increase the density of the material and/or can be manipulated to assist in discharging the material from the container by pressure of the membrane on such material. Preferably, pressure of the membrane on the material is effected by providing a differential fluid pressure on opposite sides of the membrane, the pressure being higher in the space between the membrane and the outer wall of the container. The container may be cylindrical or spherical and in the case of a cylinddrical container the axis of the container can be either horizontal or vertical, as may be best suited to the particular installation. Also, the container can be of rectangular cross section. In any case, it will usually be desirable to design the membrane to fit the particular shape of the container.

It is an object of the invention to provide one or more apertures in the membrane disposable in registry with corresponding apertures in the container through which discrete particle material can be supplied to -or discharged from the container and which apertures afford access through the membrane for other purposes. More specifically, it is an object to enable such apertures in the membrane to be sealed easily in fluidtight condition.

3,421,665 Patented Jan. 14, 1969 Another object is to provide closure means for an aperture through the membrane which can be manipulated easily and quickly to open or close the aperture and which aperture and its closure means can be constructed to withstand any differential pressure to which the membrane may be subjected without being ruptured.

It is a further object to provide attaching means adjacent to closure means which can be disconnected only when the closure means are closed so that the aperture through the membrane will not prevent an appreciable differential pressure being produced on its opposite sides.

The foregoing objects can be accomplished in membrane installations in containers of various types and shapes having either rigid or flexible walls. The attachment of the liner to a flexible or rigid container can be such as to enable the membrane to follow material in the container as it moves toward an outlet and the differential fluid pressure acting on the membrane will press material toward the outlet whether the pressure at the outlet side of the membrane is reduced or the fluid pressure at the side of the membrane opposite the outlet is increased.

FIGURE 1 is a top perspective of a railway tank car container in which an upper membrane is installed, parts being broken away, and FIGURES 2, 3 and 4 are transverse sections through the tank of FIGURE 1, showing the liner in different operative positions.

FIGURE 5 is a detail top perspective of a portion of the tank of FIGURE 1 and a corresponding portion of the liner showing a modified construction, parts being broken away.

FIGURE 6 is a vertical transverse section through a different type of railway car body in which a membrane according to the present invention is installed, and FIG- URE 7 is a similar view showing a slightly modified type of membrane.

FIGURES 8, 9 and 10 are top perspectives of a different type of container in which a membrane according to the present invention is installed, parts being broken away.

FIGURE 11 is a longitudinal section through a railway tank car including a container generally similar to that shown in FIGURE 1, but having a different type of membrane arrangement.

FIGURE 12 is a longitudinal section though a boxcar type of container and FIGURE 13 is a transverse section taken on line 13-13 of FIGURE 12.

FIGURE 14 is a top perspective of a loading port installation, with parts broken away, and FIGURE 15 is a similar view showing parts in a different position.

FIGURE 16 is a side elevation of a loading port detail illustrating a different arrangement of parts.

FIGURE 17 is a top perspective of a loading port -in stallation similar to that shown in FIGURE 14 except that the portion of the liner illustrated is of a different configuration.

FIGURE 18 is a top perspective of liner membrane closure-locking means; FIGURE 19 is a section through such means showing the parts in one operative position; FIGURE 20 is a section through such means on line 2020 of FIGURE 19; FIGURE 21 is a transverse sec tion through such means taken perpendicular to FIG- URE 20 on line 2121 of FIGURE 19; and FIGURE 22 is a section through one element of such means on line 2222 of FIGURE 21; FIGURE 23 is a section through such means similar to FIGURE 19, but showing parts in different positions.

While the various membrane installations in containers illustrated in the drawings are of different types, such installations have essentially one or more of three principal functions. The first function is that of constituting a vapor barrier and insulation element in a container. The

second function is as an element for compacting or densifying material composed of fine discrete particles to increase the weight of material which can be accommodated in a given rigid or flexible container. The third function of the membrane installation is to facilitate unloading of discrete particle material or sludges or slurries from a rigid or flexible container by exerting controlled pressure on the material for moving it while, at the same time, if desired, protecting the container in which the membrane is installed from being subjected to an internal pressure below atmospheric pressure. These principles can be utilized whether the container is a stationary storage container of flexible or rigid character or a flexible or rigid transportation container, such as a tank truck, or tank trailer, or a buoyant marine tank, or a raliway tank car.

The membrane installations of the present invention are especially concerned with containers for storing or transporting discrete particle material, which term is intended to embrace any material having reasonable flow characteristics including fine powdered material, such as flour or cement; granular material such as sugar, salt or sand; coarse particle material such as whole grain or corn kernels; chunky material such as pellets, pulp chips and briquets, and small objects such as corn cobs, fruit and vegetables, such as oranges and potatoes, which, while being of irregular shape, are nevertheless su'fliciently rounded so that they will roll one on another. All of such products are included within the term discrete particle material because all of them have the characteristics of not being liquid, of their particles not adhering into a mass and of forming a reasonably steep angle of repose when piled. It should be understood that the specific items mentioned are only intended as examples to illustrate material having the characteristics pertinent to utilization of the present invention.

A principal application for the present invention is in rail cars, which may take the form of either a tank car 1, shown in FIGURES 1, 2, 3 and 4, or hopper car 2, shown in FIGURES 6 and 7. In each of these applications of the invention a membrane 3a in FIGURES 1, 2, 3 and 4 and 3b in FIGURES 6 and 7 extends within the upper portion of the car container, preferably approximately the upper half of the car container, as a liner. The lower edge portion of this membrane is secured to the wall of the rigid container around the container periphery substantially in a horizontal plane. The membrane preferably is shaped generally complementally to the interior of the container so that it can fit the inner sides of the container walls reasonably contiguously. Thus, in FIGURES 1, 2, 3 and 4 the membrane 3a is of generally semi-cylindrical shape and the membrane 3b of FIGURES 6 and 7 is of generally rectangular pan shape. In both instances the membrane is reversible, without being detachable, so that it can move between a position lining the upper portion of the container and a position substantially inverted and sagging below the edge portion of the membrane secured to the container wall.

In each instance the membrane 3a and 3b should be of relatively strong and tough, very flexible sheet material, which preferably is inelastic. Such material may be a fabric rendered air impermeable and waterproof, such as neoprene coated nylon fabric, or the membrane can be of nonwoven material such as polyester resin sheet, available under the trade name Mylar. Such membrane materials are to be understood as merely representative. Despite the membrane installation, it is convenient to load the container from the top. In order to place the load beneath the membrane, therefore, it is necessary for the material received in the container to pass through openings in the membrane. In FIGURES 1, 2, 3 and 4 loading ports or filler openings 4 in the upper side of the container are shown as having upwardly projecting flanges encircling them. The membrane 311 is then provided with elongated necks at locations along i s l gth corresponding to the container loading ports 4. The ends of these necks can be drawn upward through the container loading ports, as shown in FIGURE 2, to maintain them in registry with the loading ports during the loading operation, and folded reversely over the loading port flanges in which position the necks 5 can be retained by an elastic or clamping band 6.

In order to maintain the membrane necks 5 open during the filling operation the membrane may be pressed into substantially contiguous contact with the inner wall of the container by connecting a suction source to an opening 7 through the upper portion of the container wall in communication with the space between such wall and the membrane. As air is sucked out of this connection the atmospheric pressure within the container will press the membrane outward into engagement with the container wall to form a liner, as shown in FIGURE 2. Since the upper portion of the membrane neck 5 is secured to the filler port 4 flange, the neck will droop in returnfolded condition within the container, as shown in FIG- URE 2.

With the liner 3a held in the position of FIGURES 1 and 2 material is loaded through the ports 4 into the car tank until it reaches a level generally like that shown in FIGURE 2. The suction applied to opening 7 can then be discontinued and fluid under pressure, in this particular case preferably being air, can be supplied to the Opening 7 to press the membrane away from the tank wall. The membrane will be pressed against the material in the tank generally in the manner shown in FIGURE 3, so as to squeeze air from the spaces between the particles of the material which air will escape through the ports 4. The material will thus be compacted and densified and thus reduced in volume. Suction can then again be applied to the connection 7 to draw the membrane back into the position of FIGURE 2 to enable additional material to be fed into the tank through the ports 4.

When the filling operation has thus been completed the securing ring 6 can be removed from the liner neck 5 to detach it from the loading port and such neck can be contracted or twisted closed, bound and pushed down through the loading port. Such port can then be covered by a suitable cap 8, as shown in FIGURE 4. Instead of the liner having necks 5 it may be possible simply to provide a cover 9 for an opening in the membrane 3a, as shown in FIGURE 5. Preferably this cover is attached to the membrane at one point so as to prevent it from sliding into the space between the liner and the tank wall inadvertently. If such a closure is used a filling spout of suitable type should be provided to extend down through the tank loading port 4 into, or through, the liner opening.

Membrane 3b in the hopper car of FIGURE 6 and 7 is similar to the membrane 3a described above, and serves the same general function. In the case of a hopper car the loading ports 4 usually are staggered along the length of the car to enable the material to be supplied more readily to opposite sides of the container. The liner necks 5 can be like those described above and when the loading has been completed they can be bound and pushed down into the upper portion of the car, as shown in FIGURE 6. In FIGURE 7 the liner openings are closed by covers 9, like that shown in FIGURE 5.

Usually such discrete particle material, if it is of powdered or granular character, is removed from a container by suction. FIGURE 4 illustrates the procedure of removing such material from the tank car 1 through the discharge port 10 by suction. During such operation either the opening 7 or the loading port 4 is uncovered to vent the space within the tank above the membrane 3a, which is in contact with the load. As the suction reduces the pressure within the material below atmospheric, the at mospheric pressure above the membrane 311 presses such membrane against the upper portion of the material which follows the material and presses it toward the outlet. During this operation the inside of the tanks upper portion is not subjected to differential pressure because the pressure both inside and outside the container is atmospheric. Also, while the pressure in the lower portion of the tank is somewhat less than atmospheric the pressure on opposite sides of the material load is equal so that little or no tendency for the lower portion of the container to be deformed occurs.

It will be appreciated that as material continues to be withdrawn from the tank the membrane 3a continues to follow the upper portion of the material downward until the tank has been emptied completely. Consequently, it is necessary for the membrane to be reversible from the upwardly extending position in FIGURE 2 to substantially a corresponding downward position. For that reason the edge of the membrane must be secured circumferentially around the car tank, as shown in FIGURE 1, approximately in the horizontal central plane of the tank. If the membrane is to be of minimum extent the necks 5 should be long enough so that they will not be stretched undesirably when the membrane is pressed against the upper portion of the load of material in the tank to compact it. While such compacting is not necessary it is highly desirable, particularly in transportation tanks, in order to increase the density of the material and consequently increase the load of a given type of material which can be transported by a given tank vehicle. Also, by subjecting the membrane to differential pressure in which the pressure below the membrane is lower, and above the membrane is higher, the membrane will act to force material toward and through the discharge port, even though the material itself, such as chunky material, would not be moved readily by suction.

In FIGURES 8, 9 and a storage tank 11 of a shape different from those of FIGURES 1 and 6 is shown having in it a membrane 3c generally comparable to the membrane 3a of the tank in FIGURE 1, and the membrane 3b in the tank of FIGURE 6. In this instance the tank would be used primarily for plant storage purposes, rather than for transportation, and is shown to be of cylindrical shape in which the axis of the tank extends vertically. The liner 3c is of generally cylindrical shape, having one end closed by a cirrcular end portion, except for a central port which may have a neck 5. The end of the membrane liner opposite the circular end wall is secured circumferentially to the wall of the tank approximately midway between the upper and lower ends of the tank. Such tank has a filling port 4 located centrally in its upper end and of a diameter corresponding generally to the diameter of the membrane neck 5. The lower end of the container has in it a discharge port 10 and such container bottom may be of hopper shape to facilitate complete emptying of the tank.

The operation of the membrane installation, shown in FIGURES 8, 9 and 10, is similar to that described in connection with FIGURES 1, 2, 3 and 4. In FIGURE 8 the membrane 3c is shown as being pressed upward into substantially contiguous engagement with the inner side of the wall of tank 11 by atmospheric pressure within the tank as the opening 7 is connected to a suction source. After the tank has been filled while such suction remains applied, the neck 5 can be removed from the filling port 4 by taking off the retaining band 6 and the neck can be bound and pushed into the tank through the filling port, as shown in FIGURE 9. When material is being removed from the tank the opening 7 can be in communication with the atmosphere and the differential pressure on opposite sides of the membrane can cause the membrane to press against the upper portion of the material in the tank and follow it down as it is discharged.

The container liner installation, shown in FIGURES 8, 9 and 10, is not suited to compaction of the material at intervals because of the short length of the neck 5 extending from the liner to the tiller opening. A longer neck could, of course, be used if desired, but even then it would be difficult to obtain such compaction of discrete particle material in the container if the container were less than half full of such material.

In FIGURE 11 a railway tank car having somewhat different features is shown. In this instance the tank has a plurality of loading ports 101 located at spaced intervals along its top. The material is unloaded from the tank through discharge hoppers 102, of which there are preferably two, located in the central portion of the tank between the membrane attachment lines 14. It is necessary to provide a discharge opening of adequate size through which to move the discrete particle material quickly. If a larger opening is desired it is usually not practical simply to enlarge a single discharge opening because the size of the hopper cone cuts too far into the side wall of the tank. On the other hand, if the tank is to be pressurized, it is not feasible simply to elongate the discharge opening lengthwise of the tank to expedite discharge of the material and to assist in conveying it away from the tank, because such a slot would decrease the circumferential strength of the tank too greatly. It is possible, however, to obtain a sufficiently great area of discharge opening by providing two, or even three, circular openings spaced lengthwise of the tank. A vent opening 103 is located in the top of the tank preferably at approximately the center.

In the particular tank shown in FIGURE 11 six loadloading ports are shown, two of which are located between the membrane attachment lines 14, two more of such ports at the top of that portion of the tank which can be lined by one membrane 311 in one end portion of the tank, and two other ports at the top of the other end portion of the tank which can be occupied by another membrane. During unloading material can be dislodged from the space between the hoppers by a bridge 104 preferably inclined downward toward the two hoppers. Flow of material from such bridge into each of the hoppers can be expedited by supplying air under pressure through a connection 105 to the cavity 106 beneath the bridge and perforatinng the bridge so that air can escape through it to loosen particulate material above the bridge, and/or the bridge can be connected resiliently to the adjacent portions of the tank and provision made for vibrating the bridge to loosen material for flow from it into the hoppers.

At the central portion of the tank between the membrane attachment lines 14 a layer of insulation 106 can be provided extending over approximately the upper quadrant of the tank. It is not necessary to have a complete layer of insulation above the end portions of the tank capable of being occupied by the membranes 3h if provision is made for spacing such membranes from the metal tank wall to provide air space by pressing the membranes down onto the load during storage. However, during slow loading under very low temperature conditions it may be desirable to provide additional insulation in the form of ribs 107 between the membranes proper and the tank wall proper to prevent condensation occurring inside the membranes, particularly if it should be necessary to interrupt such loading operation for a substantial period of time.

When it is desired to load the tank a suction source is connected to each of the pipes 108, which extends through the shell of the tank 100, to communicate with the space between the shell and a membrane 3h. Only a very small suction is required for this purpose, such as one-half a pound per square inch, or even less. At the same time the vent 103 is open to supply air under atmospheric pressure to the interiors of the membranes. Such atmospheric pressure exerted on the membrane interiors will press the membranes away from their attachment lines 14 into the tank wall-lining relationship shown in FIGURE 11. Alternatively, the connections 108 can simply be vented and a source of air under a small pressure can be connected to the pipe 103 to provide a dif- 7 ferential in pressure on opposite sides of the membranes. This latter method of providing a pressure differential on opposite sides of the membranes is, however, less deslrable during the tank loading operation.

While the membranes are being held in the wall-lining positions shown in FIGURE 11, particulate material can be loaded into the space within the membranes through one or more of the loading ports 101. While FIGURE 11 shows the membranes 3h installed in a tank of cylindrical cross section such membranes can be utilized in a tank of a different shape, such as the tank 100' shown in FIGURES l2. and 13, which has a cross-section of substantially rectangular shape. This tank is shown as serving as the body of a railway boxcar. In this instance the membranes 3i are also of substantially rectangular cross section, corresponding in shape to the interior of the tank 100', so that when suction is applied to the connections 108 and the vent 103 is open the membranes will be drawn into lining relationship to the interior of the tank, as shown in FIGURES l2 and 13.

In the tank 100 of rectangular cross section ribs 107' are provided which extend across the roof of the tank transversely of its length and part way down the side walls. These ribs constitute means for spacing the membrane away from the inner wall of the tank to avoid contiguous contact with it, which would tend to promote condensation, as discussed in connection with the ribs 107 of FIGURE 11.

To expedite loading, a plurality of loading ports 101 are provided in the top of the tank shown in FIGURES 12 and 13, and unloading of such tank can be accomplished through two or more central discharge hoppers 102'. The structure of the loading ports 101, their covers 109 and the discharge hoppers 102' and related mechanism may be essentially the same as the corersponding elements embodied in the tank construction illustrated in FIGURE 11.

When material can flow out of the discharge ports the material immediately above the hoppers 102, or 102', will move down through them first. Slope sheets 110 in FIGURE 11, and 110' in FIGURES 12 and 13, will facilitate movement of material from the side Zones of the longitudinally central compartment of the container down into the hoppers. Aeration of the bridge 104, or vibration of the bridge, will deflect material between the hoppers into one or the other of them.

When the discrete particle material in the space between the attachment means 14 has been discharged through the discharge hoppers and the faces of the bodies of material stored within the membranes have assumed a stable angle of repose, or even before such a stable condition is reached, gas under pressure may be supplied to one of the connections 108 to provide higher pressure between the corresponding membrane and the container Wall than within such membrane. Gas thus supplied may have a pressure of as much as 50 pounds per square inch, for example, but the differential pressure across the membrane should not exceed 1 /2 pounds per square inch. to force the membrane to move into the central portion of the tank in turning inside out.

In order to expedite filling of the tank several loading ports 101 are illustrated in FIGURES 11 and 12. Two of such ports at the left of each figure and two of such parts at the right of each figure are shown as being in registry with the cup-shaped membranes, respectively, when they are held in wall-lining position, as they are held during the tank-filling operation. It is therefore necessary to make provision for material to be loaded into the space within the membranes through such loading ports to pass through openings in the membranes themselves in positions corresponding to the locations of the loading ports. It is necessary, however, to insure that the openings in the membranes are closed and sealed when the loading ports are closed, so that a pressure differential can be created across each membrane for the purpose 8 of moving it into and holding it in Wall-lining position. Also it is desirable to prevent material from being deposited inadvertently in the space between the membrane and the tank wall. An expedient for accomplishing this result is illustrated in FIGURES 14 to 23.

First, it is desirable to insure that the loading port covers 109 are held positively either in the closed position, or in the open position shown in FIGURES 14 to 16. In this way it is possible to ensure that the membranes are in proper wall-lining relationship before a hatch cover can be opened to admit material. Otherwise inadvertent opening of a hatch cover could allow material to be loaded into the zone between the membrane and the tank. Each cover is supported by an arm 137 which is apertured to receive a pivot rod 138 so that the cover can be swung about the rod as an axis, and can be shifted vertically to a slight extent along the rod. A helical torsion spring 139 encircling the pivot rod 138 is connected to such rod and to the arm 137, so as to exert a force urging the cover toward the closed position. Also, a helical compression spring 140 engaged between an arm 141 on which the pivot rod 138 is mounted and the arm 137 attached to the cover exerts a force tending to lift the cover upwardly into a position to clear the loading port coaming 142.

On the side of the coaming 142 opposite the hingesupporting arm 141 is mounted a pneumatically operated latch 143. When suction is applied simultaneously to the tank connection 108 behind the membrane 3h, to the connection 146 and to the connection 154, which are interconnected as shown in FIGURE 11, the membrane will be moved into wall-lining position and the latch 143 will be released. When being closed, swinging of the cover toward registry with the coaming 142 will be stopped by engagement of a lug on the cover with the stop pin 157, shown in FIGURES 14, 15 and 16.

At the location of each loading port 101 the membrane 3g will be provided with a neck 158, which is of a length to extend upward through the coaming 142 to a location a substantial distance above the upper edge of the coaming when the membrane is in the wall-lining position of FIGURES l1 and 14. Such neck 158 is made of limp material and when its upper end is open such end can be folded down over the coaming 142, as shown in FIGURE 15, and, if desired, secured by a suitable band, or affixed to the neck itself. As discussed, prior to commencement of the loading operation the membrane 3g will be held in wall-lining position, such as by applying suction through connections 108 to the space between the membrane and the container wall and venting the interior of the membrane through connection 103. The suction at the loading port will not be appreciably impaired by such port being open because a seal encircling such port is interposed between the membrane and the container wall. Such seal is a rib which preferably is attached to the inner side of the container wall, but may be carried by the membrane. Such sealing rib can be of solid material or may be hollow as rib 159' shown in FIGURES 11 and 16.

When the membrane neck 158 has been pulled up through the coaming 142 and folded over its upper edge, as shown in FIGURE 15, material can be loaded into the interior of the membrane 3g through the loading port, such as through a supply pipe spout 160, as shown in FIGURE 16. It is not necessary for the slider 162, shown in FIGURE 18, of the zipper type of separable fastener 161 to be fully open during thefilling operation, in every instance. When a supply pipe spout 160 is extended through the neck 158 and coaming 142, as shown in FIGURE 16, the neck can be turned up around the spout and the slider can be moved toward it until the open portion of the neck embraces the spout closely. The neck 158 can be suspended in this position by attaching to a suitable hook on spout 160 a chain which is connected to a ring of the slider 162.

When a loading operation has been completed, or is interrupted, it is necessary to close the outer end of the neck 158 so that the entire membrane will be sealed in order to enable a differential pressure to be exerted on it for manipulating it. It is desirable to be able to close the end of the neck 158 quickly, easily and tightly and it is further essential that the neck not be allowed to drop down through the coaming and the loading port any great distance without being entirely closed. Mechanism capable of preventing such an occurrence is shown in FIG- URES 14 and 18 to 23. The end of the neck 158 is closed by squeezing it flat and connecting the opposite edges by the separable fastener 161. It is necessary that this separable fastener be of the type which will make a fluidtight joint when the fastener is closed.

In the form of membrane neck 158, shown in FIG- URE 17, its end when closed by the separable fastener 161 is of hemispherical shape and such separable fastener being flexible preferably follows the arc of the great circle which lies in a diametrical plane of the neck end. The portions of the hemispherical neck end at opposite sides of the separable fastener are formed by gores 158'. The edges of such 'gores may be formed by great circles and taper oppositely from their central portions to apexes at opposite ends of the separable fastener 161.

It is necessary that the zipper type of separable fastener 161 be one which will make a fluidtight joint when the fastener is closed. Lock mechanism is provided to engage the slider 162 when the fastener is closed so that the slider must be fully closed and cannot be opened inadvertently when the lock mechanism is engaged with the slider. By providing a key 163 for such lock mechanism which is carried by the end of a chain 164 anchored at the exterior of the loading port 101, it is impossible to drop the neck 158 through the loading port in opened condition without having the chain 164 connected to such neck by which it can be retrieved easily back through the loading port, and which will prevent inadvertent closure of the hatch cover unless the membrane is sealed and the key and chain withdrawn out of the hatch coaming.

The details of the slider-locking mechanism 165 carried by one side of neck 158 are shown in FIGURES 18 to 23. In one side of the locking mechanism is a bore 166 into which the stern 167 of the slider 162 can be inserted, as indicated by the arrow in FIGURE 23, into the position shown in FIGURE 20. Insertion of such stem will force to the left, from the position of FIG- URE 23 to that of FIGURE 20, a spring-pressed plunger 168 which also slides in the bore 166. Such plunger is urged toward the right, in FIGURES 20 and 23, by a compression spring 169 and its movement to the right is limited by a flange 170 on its end remote from the opening of bore 166.

When the stem 167 has been pushed fully into the bore 166 to the position shown in FIGURE 20, the shallow annular groove 171 is in registry with a bore 172 in the lock mechanism extending transversely of the bore 166 and offset slightly from such bore. The stem 173 of the key 163 may be pushed in the direction indicated by the arrows in FIGURES l9 and 21 into the bore 172 until the key reaches the position shown in FIGURE 23. At that time its shallow annular groove 174 will be in registry with the bore 166. When the key stem is not inserted in bore 172 plunger 175 is projected into such bore by the compression spring 176 into the limiting position shown in FIGURE 19, in which the flange 177 on the end of the plunger 175 is engaged with the shoulder in bore 172 spaced from the opening of such bore.

In general, the function of the locking mechanism is to insure that either the key 163 or the slider 162 will be held in the locking mechanism. When the key is held in the locking mechanism, as shown in FIGURE 18, the neck can be opened by withdrawing the slider 162 to the right, as seen in FIGURES l8 and 23, but the neck can move downward through the loading port 101 only as far as permitted by the length of chain 164 attached to the key 163. Under these circumstances the key cannot be withdrawn from the bore 172 because the plunger 168 in intersecting bore 166 will be engaged in the shallow groove 174 of the key, in the position of FIGURE 23, to prevent it from being withdrawn. The plunger 168 is, of course, held in this key-retaining position by the compression spring 169.

When it is desired to close the opening in the neck 158 and the cover 109, slider 162 is moved toward the locking mechanism to close the neck opening and its stern 167 is moved into the bore 166 from the position of FIGURE 23 to that of FIGURE 20. By such movement the plunger 168 is forced to the left to the position of FIGURE 20, so that the shallow groove 171 of the slider stem 167 is in registry with the bore 172. The key 163 can then be withdrawn from such bore and spring 176 will urge plunger 175 to follow the stem until it reaches the position shown in FIGURE 19. In that position the plunger will be lodged in the shallow groove 171 of the slider stem 167 so that it cannot be withdrawn and the slider will thus be held in fully closed position. The key 163 and its chain 164 can then be withdrawn from the loading port, the closed neck 158 can be dropped down through the loading port into a position within the container and the cover 109 can be moved into closed position.

I claim:

1. Apparatus for holding material comprising a container having a loading port in the upper portion thereof and a discharge port in the lower portion thereof, a membrane sheet disposed between such loading port and such discharge port, having an opening therethrough for passage of material from the loading port side of the membrane sheet to the discharge port side of the membrane sheet and said membrane sheet having an edge portion encircling such opening, the perimeter of said membrane sheet edge portion being of greater length than the perimeter of such membrane sheet opening, means securing and sealing said membrane sheet edge portion to the wall of said container at a location between such loading port and such discharge port, releasable connecting means for connecting such membrane sheet opening to such loading port for passage of material therethrough to the discharge port side of said membrane sheet and releasable for freeing the portion of said membrane sheet having such opening to follow material moving toward such discharge port, and closure means for closing such membrane sheet opening when said releasable connecting means are released.

2. The apparatus defined in claim 1, and a cap constituting the closure means.

3. The apparatus defined in claim 1, in which the closure means includes a zipper type of fluid-tight separable fastener.

4. The apparatus defined in claim 1, locking means for the closure means, and operating means for said locking means secured in said locking means when the closure means is open.

5. The apparatus defined in claim 4, and means connected to the operating means and anchored to the container externally of the loading port to limit downward movement of the membrane sheet portion having the opening when the closure means is open.

6. The apparatus defined in claim 3, in which the separable fastener includes a slider movable to close the separable fastener, said slider having a stem projecting therefrom, locking means carried by the membrane sheet adjacent to the opening therein and having a first bore adapted to receive said stern therein and a second bore crossing and partially intersecting said first bore, a plunger reciprocable in said second bore and engageable with said slider stem, and key means insertable in said second bore and operable to reciprocate said plunger out of position locking said slider stern.

7. The apparatus defined in claim 6, and a plunger reciprocable in the first bore and engageable with the key means for locking it in the second bore when the slider stem is withdrawn from the first bore.

8. The apparatus defined in claim 1, in which the releasable connecting means includes a neck extendable upward from the membrane sheet opening, and the closure means including a zipper type of fluid-tight separable fastener.

9. The apparatus defined in claim 1, in which the releasable connecting means includes a neck extendable upward from the membrane sheet opening and having an end of substantially hemispherical shape, the closure means being disposed substantially along a great circle of the neck end.

10. The apparatus defined in claim 1, in which the releasable connecting means includes a neck extendable upward from the membrane sheet opening through the loading port.

11. The apparatus defined in claim 1, and sealing means spaced from and encircling the loading port, spaced from and encircling the membrane sheet opening and engageable between the membrane sheet opening and the interior wall of the container for effecting a seal around the loading port and the membrane sheet opening to seal the space between the container wall and the membrane sheet for preventing communication of such space with the loading port.

12. The apparatus defined in claim 11, in which the sealing means includes a sealing rib encircling the loading port and the membrane sheet opennig.

13. The apparatus defined in claim 12, in which the sealing rib is mounted on the container, is hollow and is inflatable.

14. The apparatus defined in claim 1, in which the container is of substantially cylindrical shape and the discharge port is centered in the lower portion of the container.

15. The apparatus defined in claim 1, in which the container is of elongated shape with its length disposed generally horizontally.

16. The apparatus defined in claim 1, in which the container is disposed with its axis substantially vertical and the entire peripheral edge portion of the membrane sheet is secured to the wall of the container substantially in a horizontal plane.

17. The apparatus defined in claim 1, the edge portion of the membrane sheet being sealed to the inner side of the container Wall substantially midway between the top and the bottom of the container.

18. The apparatus defined in claim 1, the closure means being disposed substantially coplanar with the portion of the membrane sheet encircling the opening.

References Cited UNITED STATES PATENTS 2,720,375 10/1955 Carter 14168 2,815,887 12/1957 Ford et al. 222-405 2,831,610 4/1958 Dennie 222- 3,096,912 7/1963 Rivette 222105 3,058,623 10/1962 Hawk et al. 222105 3,070,810 1/1963 Jones 222183 3,105,617 10/1963 Felldin 222-185 3,206,076 9/1965 Brackett 222105 FOREIGN PATENTS 1,033,076 7/1953 France.

ROBERT B. REEVES, Primary Examiner.

H. S. LANE, Assistant Examiner.

US Cl. X.R. 222l76

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