US3080820A

US3080820A - Pumping system

Info

Publication number: US3080820A
Application number: US781765A
Authority: US
Inventors: Lindsay H Browne
Original assignee: Scott and Williams Inc
Current assignee: Scott and Williams Inc
Priority date: 1958-12-19
Filing date: 1958-12-19
Publication date: 1963-03-12
Anticipated expiration: 1980-03-12

Description

March 12, 1963 L. H. BROWNE PUMPING SYSTEM 2 Sheets-Sheet 1 Filed Dec. 19, 1958 FIG.

mm 2 4 a LY v K I m m m m I If 6 m U m 1 n n:

4 2 m m w Q/hn f i 5 w 0 2 I (5 I d 86 55 8 9 6 9 FIG. 3.

ORNEYZ ATT March 12, 1963 1.. H. BROWNE PUMPING SYSTEM 2 Sheets-Sheet 2 Filed Dec. 19, 1958 IN VEN TOR.

ATTORNEYS nit This invention relates to a pumping system and has particular reference to the pumping of materials, such as radioactive materials, wherein the actual pumping must be elfected remote from the control devices.

In my Patent No. 2,836,121, dated May 27, 1958, there is disclosed a pump which has highly desirable characteristics of operation. in these pumps, pulsators of rubber-like material serve as displacement elements to effiect pumping in arrangements which serve for local isO- lation of the material being pumped from actuating liquid and the controls producing flows of the latter. Furthermore, desirably these pumps provide substantially continuous non-pulsating flow of the material being pumped.

The isolation which is effected by the use of the pulsatons is, however, not sutlicient to satisfy the problems involved in the pumping, for example, of dangerous radioactive materials. A solution to the latter problem involves the arrangement of several pumping heads in tandem fashion with the utilization of liquid connections between them through piping serving for spatial isolation.

However, certain problems are not so simply solved since in the handling of dangerously radioactive materials it would not be considered safe to rely upon rubber or rubber-like diaphragrns or other pulsating elements to form part of the system containing the dangerous materials. The practice in this respect is to utilize an all metal construction giving rise to a "very high safety factor against puncture or leakage, -all joints being welded or otherwise made safely tight.

The utilization of metallic diaphragms, or the like, is attended with a characteristic which give-s rise to special problems, namely, the fact that such diaphragms have a very considerable stiffness which must be overcome in effecting their movements in pumping operations. In accordance with the present invention, provisions are made to operate metallic diaphragms, or other metallic displaceable walls such as bellows, in such fashion as to overcome their inherent stiffness While, nevertheless, utilizing the advantages of my pumping system in securing substantially uniform non-pulsating delivery.

The broad objects of the invention have to do with the attainment of the general results just indicated, and these and other objects particularly relating to details of construction and operation will become apparent from the following description read in conjunction with the accompanying drawings, in which:

FIGURE 1 is a vertical section through a driving liquid distributing valve and associated parts, the section being taken on the plane the trace of which is indicated at 11 in FIGURE 2;

FIGURE 2 is a horizontal section taken through the same; and

FIGURE 3 is a diagrammatic sectional view showing actuating and pumping heads associated with and adapted to be operated by the mechanism shown in FIGURES 1 :and 2.

There will first be described the primary pumping means which is desirably utilized in the present system and which will be found to correspond very closely in many respects to what is described in my Patent No. 2,836,121.

The particular spatial arrangement of the various parts arm ice

of the primary pumping means is not of major consequence and, accordingly, various elements are indicated diagrammatically in rather arbitrary location. A driv ing motor 2 serves to drive through shaft connections indicated at 4 reduction gearing indicated as located within a housing 6 by which, in turn, there is driven a shaft 8 carrying a'crank 10 which through link 12 and pin 14 senves to reciprocate a slide 16 in a guideway 18 provided in a valve block 20. The various elements so far described are desirably located within a pump housing a portion of the wall of which is indicated at 21, this housing also enclosing a primary pump 23 (FIGURE 2) which is driven by the motor 2. The pump 23 may be of any of a large variety of positive types. It has been found, for example, that one highly satisfactory form of pump is of multiple piston, variable delivery type, which is capable of providing an output reasonably continuous and free from pulsation. -In such a pump, for example, variation of displacement from zero to some maximum capacity may be controlled by a manual adjusting device, though the adjustment of the pump may he automatically controlled either pneumatically or electrical y. Rotary piston or other types of positive variable delivery pumps may also be used. The particular driving pump here used does not, in itself, constitute a part of the invention, the invention being concerned only with the use of a positive pump desirably having substantially uniform displacement, and under some circumstances, desirably adjustable as to delivery rate. A constant rate pump may be used where adjustability is not required. Conveniently, the housing which encloses the elements described, including the pump, may provide an oil sump from which oil may be pumped through the system with delivery back to the sump. The oil used may be any suitable lubricating oil and may serve not only as the driving liquid but also for lubrication of the mechanically operating parts.

A valve cylinder 26 is located with a press fit in a bore 24 in the block 20, and arranged to reciprocate in cylinder 26 is a driving liquid distributing valve generally designated 28. This valve comprises the

main pistons

30 and 32 and end pistons 34 and 36. The spindle of the valve is bored at its ends to receive rods 33 which are arranged to be engaged by discs 22 threaded on studs 25 secured in the ends of the slide 16, the discs being located in binding condition against the rods 38 and held by lock nuts. The purpose of the arrangement just described is to provide axial adjustability of the. valve 28 with respect to the slide 16 to provide for proper phasing of its respective operations as hereafter described. Through the connections from crank it) the valve is given approximately simple harmonic motion for control of the driving liquid flow. A central port 40 is provided in block 20 and cylinder 26 to serve for the introduction of operating liquid through pipe 41 from the pump 23.

Various ports are provided in axially displaced positions along the cylinder 26 and provide communication between its bore and annular spaces about the cylinder provided in the block 24). Each of these'ports desirably consists of a number of radial holes through the cylinder, as indicatcd in FIGURE 1, to provide free flow of the driving liquid, but for convenience will be hereafter referred to in the singular. 7

Ports

42 and 44 provide for delivery of the driving liquid from the central portion of the cylinder 26. These ports communicate with the

spaces

46 and 48 in the block 29.

Ports 5G and 52 provide for the exhaust of driving liquid from pulsators hereafter described and communicate with the

spaces

54 and 56 in the block 20.

Ports

58 and 60 provide for exhaust of the operating 3 liquid from the cylinder 26 and communicate with the spaces 62 and 64 in the block. The spaces 62 and 64 are respectively ported at 66 and 68 to connecting pipes 67 and 69 which serve to return the exhausted driving liquid to the sump.

As will appear hereafter, the valve pistons serve to control flows through the various cylinder ports.

The

spaces

54 and 56 are in communication with passages 7t and 72 in the block 29.

Spaces

46 and 48 communicatc with the openings through valve seats 7 8 and 80 which are, respectively, controlled by ball check valves 74 and 76 above which, as viewedin FIGURE 2', are located passages 75 and 77 communicating, respectively, through

lateral passages

90 and 92 with the passages 70 and 72. Inwardly directed fins 93 guide the balls and provide for passage of liquid 'by the balls. Springs 82 and 84 serve to urge the balls 74 and 76 towardseated position, these springs being located within plugs 86 and 88 in the passages 75 and 77, the plugs being provided with packing to provide against leakage from these passages. Snap rings 79 and 81 hold the plugs 86 and 88 in position. The bores 70 and 72 are in communication with

bores

99 and 97, respectively, provided in a block 94 which is mounted on the wall 21 of the housing and serves to support, in an opening through this wall, the block 20. Sealing between the block 20 and block 94 at the passages is provided by O-rings as illustrated in FIGURE 2. Communicating with the

bores

97 and 99 are

pipes

96 and 98 extending to pulsators.

Consideration may now be given to FIGURE 3 which shows the elements of the pumping system beyond the

pipes

96 and 98 and terminating with the pumping head handling the ultimate material to be pumped. In FIG- URE 3, the elements associated with pipe 96 are shown in detail, and it will be understood that identical elements are associated with pipe 98, there being at the right-hand end of this figure the ultimate valves associated with the particular pumping head associated with pipe 98.

A pulsator head generally designated '150 comprises a pair of housing members 152 and 154'providing between them a chamber 155 in which is mounted a diaphragm 156. This diaphragm may be of suitable metallic construction and may be welded at its periphery between and to the

members

152 and 154. It will be understood that the showing of this diaphragmis more, or less diagrammatic and that the diaphragm, desirably metallic, may actually consist of a metallic bellows, or the like, providing a displaceable wall. Whatever its form, for the purposes for which the invention is primarily intended, it will ordinarily have considerable stiffness. 96 communicates with the chamber 155 at 158 at the lefthand side of the diaphragm 156.

The chamber 155 at the other side of the diaphragm comunicates through openings 160 with a bore 162 which communicates with the interior of 'a standpipe 164 desirably of enlarged horizontal cross-section which is provided with a tubular extension 166 at its upper end which is arranged to be sealed off, for example, by welding, after the system is filled with liquids. The portion of chamber 155 to the right of diaphragm 156 and the passages communicating therewith and the lower part of standpipe 164 are desirably filled'with heavy liquid 168, such as mercury, which as will appearis provided to impose a large static head at theright side of diaphragm 156. The standpipe is provided withsufii cient volume so that the liquid 168 which will hereafter be referred to as mercury will not pass into tube 172 communicating with the upper end of thestandpipe, which tube 172 and the upper portion of thestandpipe are filled with lighterliquid 170 such as water.

The tube 172 may pass through a heat exchanger such as 174 which may be provided, if required, for cooling purposes and thence-at 176 communicates with a pumping head 189 which to a considerable extent involves the same construction as the actuating head 150 comprising The pipe 7

housing members

182 and 184 providing between them a chamber 185 within which is located a diaphragm 186 which may also be of stiff metallic material. The pipe 176 communicates with the portion of the chamber 185 to the left of the diaphragm 186 at 188. The righthand side of this chamber communicates through passages 190 with a bore 192 which at its lower end communicates wtih a supply of the material being pumped (which may be a liquid, :1 liquid containing a suspended solid material, a vapor or gas) through one or more check valves indicated at 194. At its upper end the *bore 192 communicates with a delivery line for the pumped material through one or more check valves 196. (The reason for indicating check valves in tandem is that in operations involving dangerous materials it is usually desirable to insure against any faulty operation by the use of check valves in series, though from the standpoint of normal operation these are merely the equivalent of a single check valve.)

While the elements communicating with pipe 98 are not detailed, it will be understood that they are identical with those shown in FIGURE 3 as connected with pipe 96, and there are shown at the right of FIGURE 3 the check valves 194' and 196' of the pumping head 18!) associated with pipe 98. The lower check valves 194 and 194' communicate with a material intake manifold 198 and the

outlet check valve

196 and 196 communicate with a delivery manifold 200.

The

pipes

96 and 98 and 172 and that corresponding with the other assembly which is not detailed may obviously be of any desired length serving to provide isolation such as may be required for the material being pumped. Oil is desirably the liquid which flows through

pipes

96 and 98, while Water may be the liquid in pipe 172 and its counterpart.

If it were assumed that the

diaphragms

156 and 186 involved no substantial stiffness, the system would operateeven in the absence of the mercury head to provide continuous non-pulsating delivery of the material being pumped through the manifold 200 for reasons set forth more fully below. In such case, the effect would be essentially that of the

diaphragms

156 and 186 being equiv-- alent to pulsators of the type described in my prior patent, the liquid connections being merely transfer connections for the displacements involved. The sum of the displacements of the diaphragms 186 of the two pumping heads. toward the right to efiect pumping would be constant, though the intakes of the material being pumped through the intake manifold 198 and the

valves

194 and 194" would be intermittent. These pumping conditions arenot disturbed by the inclusion of the elements which have been shown and described but they become necessary forthe following reasons:

The stiffness of the diaphragm 156, resisting its movement to an extreme left-hand position as illustrated in FIGURE 3, might involve a substantial pressure difference forming a large percentage of atmospheric pressure or even exceeding that pressure. Then, in turn, even assuming some residual pressure difference, only this residual pressure difference would be available toovercome the stiffness of the diaphragm 186 and the possible suction required at the inlet for the material being pumped. Accordingly, there are provided the mercury columns which have been described. As the diaphragm 156 is forced to the right under the full pressure exerted by the pump 23, which may be very high,

the mercury column is raised. Then when conditions for the collapse of the pulsator occurs, the mercury column exerts the necessary pressure to drive the diaphragm 156 to its left-hand position, leaving for the driving of the diaphragm 186 essentially atmospheric pressure less only the vapor pressure of the water or other liquid in pipe 172. The diaphragm 186 must, of course, be made such as to be properly moved toward the left by the pressure gradient thus available. It will be evident that the foregoing considerations will not disturb the condition, described below, of securing non-pulsating pumping action in the heads 1% and 18d.

There may now be considered the matters which should be taken into account to prevent damage and to secure proper operation despite temperature changes. The liquid spaces between the right-hand side of diaphragm 156 and the left-hand side of diaphragm 186 should be charged with the liquids (for example, mercury and water) and sealed when the system is at its minimum temperature and with the

diaphragms

156 and 186 in their extreme lefthand positions, the extreme left-hand position of diaphragm 186 being desirably with some clearance with the left-hand wall of the chamber 135. Thereafter, if the temperature rises in the system, the diaphragm 186 cannot under any conditions again come in contact with the left side of its housing nor can it come in contact with the right side of its housing if the chamber 185 is of sufficient size (desirably substantially in excess of that of chamber 155), since its movements ar limited by the maximum displacements imparted to it by the displacement of diaphragm 156. Thus, the diaphragm 186 cannot be subject to hydraulic shock due to interrupted discharge by bottoming. The diaphragm 156, on the other hand, is intended to attain its extreme left-hand position,

as illustrated in FIGURE 3, upon each suction stroke, but the force on contact will be no greater than that im posed by the pressure exerted by the mercury column, assuming a zero suction head or" the material being pumped. it follows that the stroke of diaphragm 156 always starts from precisely the same extreme left-hand position in each pumping cycle. It may be remarked that any change in volume in the oil connections (pipes 96 and 9%) will be relieved automatically when the distributor valve 23 effects opening to atmosphere once per cycle.

The operation which provides smooth non-pulsating flow is as follows:

Preliminarily, it may be remarked that the rate of rotation of the shaft 8 for the purpose of reciprocating the distributing valve 22% through its cycles is such that, considering the maximum delivery of pump 23, it the delivery rate of the pump is adjustable, the pulsators 156 and that corresponding thereto connected with the pipe 98 will not be displaced during any cycle toward the right as viewed in FIGURE 3 to such extent as to cause them to engage the walls of their respective chambers. Variations in delivery rate of the pumping liquid by pump 23 then merely involves less displacement of the pulsators to provide corresponding displacement of the liquid being pumped.

There may be first assumed the conditions involved when the valve 2% occupies its extreme left-hand position as viewed in PEGURE 2. Under that condition, the port &2, is in communication with the supply port 40 for the operating liquid which will then be flowing past valve 74 shown as open in FIGURE 2 and through passages 99, 7 (i and 9% to provide expansion of the pulsator connected to pipe 98. As this flow continues, the pulsator reduces the volume in its pumping chamber providing outflow of the mercury. Outflow port 5t) is closed by piston 30-. The inlet port 44 is closed by piston 32. Ports 52 and 6d are in communicationwith each other through the space between the pistons 32 and 36 and are also in communication with the outlet port 63. While check valve *76 is now closed, the interior of the pulsator connected thereto is in free communication with the outlet and this pulsator will be in collapsed condition under its head of mercury.

As the valve 28 moves toward the right from its lefthand position, the piston 3t) continues to close port 50 and will not then have started to close the port 42. Port 44 remains closed by piston 32 but this piston will now have closed the port 52, cutting oil communication be tween the interior of the corresponding pulsator and the discharge port 63. Actually, at this time the pulsator will have been fully collapsed, and, consequently, flow right.

through the port 52 will have ceased before. the piston closes this port. Inasmuch as port 42 is still open for the passage of the operating liquid, the other pulsator will continue to expand.

The next event is the location of the valve 2.3 in a position characterized by the beginning of opening of port 44 to the operating liquid. As this port 44 is cracked open, there would occur a tendency for flow to take place from the expanded pulsator to the collapsed pulsator. if such action occurred, there would be produced, in view of the high pressures involved, a transient shock due to the interchange of liquid from one pulsator to the other. However, such transfer of the operating liquid is prevented by the closure or check valve 74- under the action of spring 82. This check valve may close because, even though port 42 is open to the operating liquid supply, the pressure exerted inwardly by the expanded pulsator exceeds the inward pressure exerted by the collapsed pulsator. This condition continues in fact, as the pulsator expands due to the flow of operating liquid thereinto inasmuch as until it receives the full volume of operating liquid it will be less expanded than the previously expanded pulsator. Accordingly, the incoming operating liquid following the attainment of the conditions just escribed will flow only into the newly expanding pulsator. As this expands it displaces mercury into its corresponding column. The condition existing, therefore, is that for a short interval after the attainment of these conditions the previously expanded pulsator will remain essentially in its fully expanded condition.

As further displacement of the valve 28 occurs with cut-off of port 42, flow continues into the newly expanding pulsator through port 44 and past check valve '76 with no flow (with the exception of possible slight leakage) through port 42 in either direction. If any slight leakage occurs, it would be from the fully expanded pulsator past check valve 74- and through the space between pistons 36 and 32 to the other pulsator under a relatively small head due to difierent extents of expansion or" the pulsators. Such slight flow, however, will not produce any noticeable transient in the nature of shock. Port remains closed.

The piston 3t then starts to open the port 59. The previously fully expanded pulsator is thus brought into communication through passages 99 and and the space between pistons 3th and 34 and port 58 with the outlet passages 66, 67. In the absence of piston '34, the sudden application of pressure at the left of piston 36' would cause the valve 28 to receive a sharp impulse toward the However, with piston 34 provided, there is involved equalization of pressures efiective on the valve 28 to avoid the occurrence of a transient at this time. The expanded pulsator now collapses due to its column of mercury. At this time, port 44 remains open so that flow of operating liquid continues to expand the other pulsator. v

The final movement of valve 28 involves no new operation, the collapsing pulsator being completely collapsed before this final condition is reached, while the expanding pulsator continues to receive operating liquid through the port 44.

It will be evident that the return of the valve to the initial position mentioned involves merely repetition of the phases of the cycle but with inverse respect to the two pulsators.

Despite the intermittent openings and closings of ports, it will be noted that the sum of the expanded displacements of the two pulsators is continuous. The continuous supply of operating liquid involves, in particular, total displacements of the two pulsators, first one, then possibly both, and then the other in such fashion that the total of the expanded displacements in the chambers 1'55 remain constant.

While the complete system disclosed is arranged to provide non-pulsating pumping, it will be evident that various aspects of the invention are not limited theretobut may be used in systems in which pulsation in the outflow is permissible and wherein, for example, the fiow' of liquid in connections such as 96 and 98 may be due to the expansions and contractions of pulsating elements. merely arranged as in my Patent No. 2,738,731, dated. March 20, 1956, wherein pulsating pumping is effected. possibly relieved only to some extent by the operation, of a plurality of pulsators operated out of phase. In, such an arrangement, there would still be much utility in providing the equivalent of the mercury column arrangement where transfer of displacements was required. to be efiected through inherently stiff diaphragms or theirequivalents.

What is claimed is:

1. A pumping system comprising a housing, a movable diaphragm having substantial stififness, said housing coop crating with said diaphragm to define a pair of chambersv on opposite sides of said diaphragm, means for supplying a pulsating fiow of liquid into and out of one of said. chambers, pumping means driven by liquid pressure, and a conduit filled with liquid and providing communication. between the other said chamber and said pumping means, a portion of said conduit including a standpipe extending upwardly with respect to said diaphragm, the liquid in said standpipe exerting a static pressure head on said diaphragm and said pumping means being driven by liquid pressure communicated thereto through said conduit.

2. A pumping system comprising a housing, a movable diaphragm having substantial stifiness, said housing coopcrating with said diaphragm to define a pair of chambers on opposite sides of said diaphragm, means for supplying pulsating flow of liquid into and out of one of said chambers, a conduit for liquid communicating with the other of said chambers, said conduit including means providing a standpipe for the exertion of liquid pressure on said diaphragm, said conduit containing a pair of liquids of substantially different specific gravities, the liquid of greater specific gravity being in contact with said diaphragm and having an interface with the liquid of less specific gravity in said means providing a standpipe, and pumping means communicating with said other chamber through said standpipe and driven by the liquid pressure therein.

3. A pumping system according to claim 2 in which the liquid of greater specific gravity is mercury,

4. A pumping system in which there are two complete sets of the elements specified in claim 2 and in which the movable diaphragms substantially alternate in their movements.

5. A pumping system comprising a housing, a movable diaphragm having substantial stillness, said housing cooperating with said diaphragm to define a pair of chambers on opposite sides of said diaphragm, means for supplying pulsating flow of liquid into and out of one of said chambers, a conduit for liquid communicating with the other of said chambers, said conduit including means providing a standpipe for the exertion of liquid pressure on said diaphragm against the pressure exerted by said pulsating flow, a second housing, a second movable dia phragm cooperating with said second housing to define a second pair of chambers on opposite sides of the second diaphragm, said conduit being connected with one of the last mentioned pair of chambers, and means providing inlet and outlet passages to and from the other of the last mentioned pair of chambers for fluid to be pumped.

6. A pumping system comprising a housing, a movable diaphragm having substantial stiffness, said housing cooperating with said diaphragm to define a pair of chambers on opposite sides of said diaphragm, means for supplying pulsating flow of liquid into and out of one of said chambers, a conduit for liquid communicating with the other of said chambers, said conduit including means providing a standpipe for the exertion of liquid pressure on said diaphragm, said conduit containing a pair of liquids of substantially different specific gravities, the liquid of greater specific gravity being in contact with said diaphragm and having an interface with the liquid of less specific gravity in said means providing a standpipe, a second housing, a second movable diaphragm cooperating with said second housing to define a second pair of chambers on opposite sides of the second diaphragm, said conduit being connected with one of the last mentioned pair of chambers, and means providing inlet and outlet passages to and from the other of the last mentioned pair of chambers for fluid to be pumped.

7. A pumping system according to claim 6 in which the liquid of greater specific gravity is mercury.

8. A pumping system in which there are two complete sets of the elements specified in claim 5, in which the first mentioned movable diaphragms substantially alternate in their movements, and in which said inlet passages are joined and in which said outlet passages are joined for the pumping of the same fluid.

'9. A pumping system in which there are two complete sets of the elements specified in claim 6, in which the first mentioned movable diaphragms substantially alternate in their movements, and in which said inlet passages are joined and in which said outlet passages are joined for the pumping of the same fluid.

10. A pumping system according to claim 8 in which said means for supplying pulsating flows of liquids to the first mentioned diaphragms comprise valve means for controlling the pulsating flow to effect substantially constant total driving displacements of said firstmentioned diaphragms.

11. A pumping system according to claim 9 in which said means for supplying pulsating flows of liquids to the first mentioned diaphragms comprise valve means for controlling the pulsating flow to eitect substantially constant total driving displacements of said first-mentioned diaphragms.

References fiitcd in the file of this patent UNITED STATES PATENTS 1,101,266 Franklin June 23, 1914 2,452,526 Osborne Oct. 26, 1948 2,915,016 Weaver et al. Dec. 1, 1959 FOREIGN PATENTS 473,442 Italy July 28, 1952 1,122,901 France Sept. 14, 1956

Claims

1. A PUMPING SYSTEM COMPRISING A HOUSING, A MOVABLE DIAPHRAGM HAVING SUBSTANTIAL STIFFNESS, SAID HOUSING COOPERATING WITH SAID DIAPHRAGM TO DEFINE A PAIR OF CHAMBERS ON OPPOSITE SIDES OF SAID DIAPHRAGM, MEANS FOR SUPPLYING A PULSATING FLOW OF LIQUID INTO AND OUT OF ONE OF SAID CHAMBERS, PUMPING MEANS DRIVEN BY LIQUID PRESSURE, AND A CONDUIT FILLED WITH LIQUID AND PROVIDING COMMUNICATION BETWEEN THE OTHER SAID CHAMBER AND SAID PUMPING MEANS, A PORTION OF SAID CONDUIT INCLUDING A STANDPIPE EXTENDING UPWARDLY WITH RESPECT TO SAID DIAPHRAGM, THE LIQUID IN SAID STANDPIPE EXERTING A STATIC PRESSURE HEAD ON SAID DIAPHRAGM AND SAID PUMPING MEANS BEING DRIVEN BY LIQUID PRESSURE COMMUNICATED THERETO THROUGH SAID CONDUIT.