US3048114A - Pumps - Google Patents

Description

Aug. 7, 1962 1.. H. BROWNE PUMPS 4 Sheets-Sheet 1 Filed Nov. 19, 1957 FIG.

INVENTOR. LINDSAY H. BROWNE 4421 ATTORNEYS Aug. 7, 1962 Filed Nov. 19, 1957 L. H. BROWNE PUMPS 4 Sheets-Sheet 2 FIG. 2'.

INVENTOR.

LINDSAY H. BROWNE ATTORNEY L. H. BROWNE Aug. 7, 1962 PUMPS 4 Sheets-Sheet 3 Filed Nov. 19, 1957 m N w E E O A W MW A H L m w s 1 Y.

L. H. BROWNE Aug. 7, 1962 PUMPS 4 Sheets-Sheet 4 Filed Nov. 19, 1957 LINDSAY H. BROWNE BY, mm

FIG. 5.

ATTORNEYS I lhil lddl l- Patented Aug. 7, 19 52 3,tl42l,ll4 PUMPS Lindsay H. lirovvne, Westport, Conn, assignor to Scott 8; Williams, Incorporated, Laconia, N.H., a corporation of Massachusetts Filed Nov. 19, 1957, Ser. No. 697,343

It Claims. (tCl. ltl34l i) This invention relates to pumps and ha particular reference to pumps oi the pulsating type in which an operating liquid is completely isolated from the liquid being pumped. Pumps of the type to which the present invention relates are disclosed in my applications, Serial Nos. 265,769, now abandoned, and 361,225, now U.S. Patent No. 2,836,121, issued May 27, 1958, filed, respectively, January 10, 1952 and June 12, 1953.

As disclosed in said applications, a pair of pulsators may be so operated that, when supplied with a continuous flow of driving liquid, they will provide a substantially continuous flow of the liquid being pumped. The statement that the flow is substantially continuous does not here imply that there is any appreciable deviation percentagewise from accurately continuous ilow. Actually, the only deviation from precise continuity is involved in the occurrence of transient pulses of short duration which are more in the nature of sound waves than measurable deviations of flow rate. The latter of the aforementioned applications i particularly concerned with the minimizing of such transient shock pulsations.

By the use of such pumps extremely high pressures may be developed in the pumped liquids. Furthermore, the liquids which are being pumped may contain solid materials, possibly being in the form of thick sludges, pumping being satisfactorily obtained without hindranc from the solid materials. The present invention is particularly directed to pumps of this type of large capacity and capable of handling sludges or the like which ofier particular difliculties in pumping.

One of the objects of the present invention is the provision of improved pulsators which may be of very large size and which would be difficult to provide in the form of the thimbles disclosed in said prior applications.

A further object of the invention relates to an arrangement of pulsators whereby troubleproof operation with thick sludges is particularly obtained.

Still another object of the present invention is the provision of means for bleeding air or gases from the material being pumped so as to prevent their accumulation.

The foregoing and other objects of the invention 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 an elevation of a pump provided in accordance with the invention;

FIGURE 2 is a plan view of the same;

FIGURE 3 is a vertical section taken through one of the pulsators provided in accordance with the invention;

FIGURE 4 is a transverse section taken on the surface the trace of which is indicated at 4-4 in FIGURE 3;

FIGURE 5 is a vertical section taken through an air bleeding valve provided in accordance with the invention; and

FIGURE 6 is a fragmentary section showing the details of construction of a pulsator.

Referring first particularly to FIGURES 1 and 2, the

complete pump comprises a base 2 taking the form of a tank providing a supply of driving liquid which desirably consists of a lubricating oil. Such a driving liquid is clean and provides no difiiculties in the way of entrained solid materials and furthermore provides lubrication for the moving parts involved in its handling. A driving motor 4 provides the power drive through a coupling 6 of a positive pump 8 which may take any of numerous forms. It may, for example, be 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 be automatically controlled either pneumatically or electrically. Another desirable form of possible pump, the arrangements for which are specifically shown herein, may be of the multiple screw rotary type indicated at 8. Such pump provides its delivery through connection It) and receives the driving liquid from the tank 2 through connection 12, meter 14, and pump inlet connection 16. Since constant speed motor drive isv desirable, and since a multiple screw positive pump of this type has a constant displacement for each revolution of its driving shaft, variable delivery requires. lay-passing of variable proportions of its flow from the outlet back to the inlet. Pro,- vision for this is indicated in FIGURE 2, where a by-pass connection at 18 is connected through a manually variable fiow controller 29 and returned to the inlet 16 through connection 22. The variable flow controlling means at 20 may be of conventional type providing an adjustable throttling control to provide the bypass of more or less of the liquid. The control is such, nevertheless, that viewing the pump assembly as a whole, a positive high pressure controlled flow is secured at 10.

The motor 4 drives through reduction gearing 24 a crank and link connection to the operating rod arrangement of a pair of distributing valves 28 and 30. These distributing valves, in effect, provide a unitary valve for distribution of the driving liquid to a pair of pulsators. Together they constitute a distributing valve which may be identical from the standpoint of its cycling operations to the valve arrangement shown in my patent, No. 2,836,121. In the present instance, merely to associate more intimately with the pulsators the particular valve elements individually associated with them, the valve of said prior application has been, in efiect, split into two portions interconnected by a linkage arrangement shown at 31 in FIGURE 1. Otherwise, the valve is the same as that shown in said prior application and need not be here described in detail. In brief, the valve arrangement is provided with the driving liquid from connection 10, the half of the valve shown at 30 receiving its liquid through a branch connection 32. Discharge from the valve back to the tank 2 occurs tln-ough the passages 36. The valve operation is such that the driving liquid i delivered from one of the valve halves to its corresponding pulsator, from both halves to both pulsators simultaneously, and from the other half to the other pulsator in a cycle of operation, with provision for exhausting the driving liquid from the pulsators when they are to collapse. Considering the sum of displacements of the two pulsators, this sum is at all times constant, being made up by the displacement of one or the other or by the displacements of both simultaneously. The result, as detailed in my applications referred to above is the provision of a substantially constant product flow, the deviations of flow from a complete condition of constancy being only by way of transients which are minimized by the adoption of the valve arrangement in the latter of said applications. Delivery of the pumped product is constant but introduction into the pulsators is intermittent. The present invention is not directly concerned with the pumping cycle provided in accordance with the foregoing, and reference may be made to said prior applications for details of the cyclical operation.

The motor 4 further drives a recirculating pump 38 for the driving liquid, the recirculation being through a cooler it? to maintain a proper maximum temperature of this liquid which becomes heated due to the energy transformations involved.

The pumped liquid, also herein referred to as the pumped product, is introduced into a header 4-2 connected to the inlets of a plurality of check valves 44. Whileonly .one such check valve is essential for each pulsator, it is desirable in the handling of products which may contain a large amount of solid material to provide a pair of such check valves in parallel for each pulsator, and that is illustrated, the-paralleled check valves in the case of each pulsator having an outlet connection at 46. The check valves are desirably of the type illustrated and described in. my copending application, Serial No. 694,258, filed November 4, 1957, now Patent No. 2,977,974 of April 4, 1961.

As shown therein, there is desirable a valve arrangement providing rubber interengaging valve and seat elements of such-type as to operate consistently and reliably despite the presence of solid materials and arranged to clear from the valve and seat elements such solid particles as may temporarily tend to accumulate. It will be understood, of course, that other types of valves may be here used, particularly where the product pumped does not ofier difiiculties by reason of abrasive or other solid constituents.

Connected also tothe common connections 56 are the inlets of discharge check valves which for reasons of insured reliability are also duplicated for each pulsator as indicated at 48. These valves may also be of the type just indicated. They deliver the product from their outlets to the discharge header 50.

Each of the pulsators comprises a cylindrical tube 52 connected at its lower end with the corresponding connection 46. As has been indicated, the present invention is particularly applicable to a large capacity pump, and in a typical arrangement these cylinders may be approximately ten feet high and sixteen inches in diameter. These figures are given by Way of illustration to indicate the reasons for the adoption and advantages of certain aspects of the invention. Each cylinder is provided with a top closure 54 carrying a central tube 56 provided with a closure 58 at its lower end and open at its upper end 6t) to communicate with the driving liquid connection 34-. The tube 56 is provided with drilled openings 62 through the extent of the operating region of a pulsator tube 64, the cylinder 56 having a somewhat reduced diameter at its exterior as indicated at 65 throughout this same region. The pulsator tube 64 is clamped at its ends to the tube 56 by means of metal bands 66 and 68. While in FIG- URES 3 and 4 the pulsator tube 64 is indicated in a conventionalized fashion, it has a detailed construction which will be described in connection with FIGURE 6. A number of longitudinally extending ribs 79 are welded tothe interior of each of the cylinders 52,, and are provided for the purpose-of preventing any circumferential portion of the pulsator tube 64 from sealing against the cylindrical inner surface of the cylinder 52, thereby preventing any possible isolation of the upper portion of the annular product space from a lower portion thereof. The stiffness of the pulsator tube 64 prevents it from completely wrapping itself about and against the rib surfaces sothat liquid communication is at all times maintained throughout the height of the annular chamber.

Details of the pulsator tube construction are shown in FIGURE 6. The construction is a laminated one as follows:

Three layers 72 of neoprene are innermost, these layers being desirably provided by sheeting with the longitudinal edges abutting and sealed, the longitudinal joints of the three layers being displaced by 120 with respect to each other circumferentially. The next layer 74 is of rubber. Throughout the central working portion of the pulsator tube there are then superimposed layers 76 of rubber and in a typical arrangement there may be ten of these. At their end portions they are bonded to and enclose a steel ring '78 which serves the purpose of preventing the transfer of stresses from the working central portion of the pulsator tube to its ends. The end portions of the tube comprise alternate layers of rubber 80 and intermediate layers of canvas 82. All of the layers are bonded together, and at the ends of the tube there are desirably provided metal caps in the form of rings 84. The bands 66 and 68, previously mentioned, clamp the end portions consisting of the alternate rubber and canvas layers. The construction described has been found particularly satisfactory to provide the pulsator tube for a large pump of the type already indicated. The portion of the tube between the rings 78 is arranged to flex outwardly under the pressure of driving liquid in its interior provided through the openings 62 in the tube 56, the outward fiexure reducing the annular volume which contains the pumped product. At the same time, the construction is such that the pulsator tube will collapse to its original unstressed condition about the tube 56 when the interior pressure is removed, with this collapse taking place despite the existence of even a complete vacuum in the product space. This latter condition is very important, since it means that before each expansion of the pulsator tube the expansion will begin from a definite position of this tube despite the possibility that the product discharge valves may have closed and the product inlet valves may have faiied to open. f there was such an occurrence and the pulsator tube 64 had not fully collapsed, there would be the danger that on the next pumping expansion it would be forced outwardly under the possibly very high interior pressure to such extent as to be ruptured. Under normal circumstances, the volume of pumping liquid introduced in each cycle would not be suiiicient to expand the tube *4. to any undue extent. In fact, in normal operation, the expansion would be limited to such extent that the tube 64- would not engage the ribs 70.

The materials used in the construction depend, of course, upon the material to be pumped and the driving liquid. Neoprene is used as the innermost layer because of its resistance to deterioration by lubricating oil. Natural or other synthetic rubber is desirably used for the exterior plies '76 and 30 where the nature of the pumped liquid permits. The metal parts in contact with the pumped liquid are so chosen as to resist the action of this liquid, stainless steel, or other highly resistant metal being used where corrosion is a problem and abrasion resistant metals being used where abrasion might otherwise produce rapid wear.

The vertical arrangement of the pulsator assemblies with the inlet and outlet connections and valves at the lower ends thereof is particularly advantageous in the pumping of sludges or other liquids containing solid materials. The tendency of the solids to settle by gravity will maintain at least their highest concentrations at the lower ends of the cylinders 52 at positions where they will be most effectively rapidly discharged by the relatively high ratesof flows through the outlet valves. The portions of the pumped liquid in the upper ends of the cylinders 52 will be relatively stagnant and it is undesirable to have more than a minimum of solid materials reach these regions.

Provided at the tops of the connections 34 are vents 83 controlled by manually operable valves 86. These vents are used in starting up the pump to remove accumulated air or gases in the driving liquid.

The accumulation of air or gases in the pumped liquid in the upper portions of the cylinder 52 would be detrimental to the proper pumping by introducing elasticity, and since accumulation of air or gases cannot be prevented by complete removal of them from the liquid being pumped, provision is made for automatically getting rid of such accumulation. For this purpose there is provided the valve arrangement illustrated in FIG- URE 5.

A vent passage 9t? is provided from the uppermost end of each cylinder 52 being connected at 92 to a passage 94 communicating with a transverse passage 96 in the lower element 98 associated with an upper element 99 to provide an air venting valve liltl. A passage N2 communicating with 9r: contains a check valve including the ball 164, the check valve communicating at lite with a tube 1% which is returned to the discharge region of one of the check valves 4%, i.e., in effect, to the product discharge manifold 563. Another passage lltl communicates through a valve comprising the ball 112 and the opening 114 to a vent tube 118. While the ball 112 cooperates with a seat and has the same general construction and arrangement as the ball N4- of the check valve, in this case the ball operates as part of a shutofit valve, being arranged to be clamped on its seat by the stem of a screw 129.

The valve arrangement at 1% operates as follows:

In starting up the pump, it may be desirable to hood the product space in the cylinder 52, and for this purpose the valve 112 may be opened, by release by the screw 12%, to vent air. This valve is then held closed by the screw.

During operation, air or other gas may tend to accurnulate in the upper end of a cylinder 52. The light ball M14 is more readily opened by pressure existing below it than the product check valves 4-8, and consequently when the pressure in the product space within cylinder 52 reaches the discharge manifold pressure both valve M4 and the valves 48 will open but the opening of the valve llll l will slightly precede the opening of the check valves 4-3 which, as will be apparent from the description in my aforesaid Patent No. 2,977,974 of April 4, 1961, tends to remain closed due to the excess area presented by its rnovable member to the discharge manifold as contrasted with that presented on its intake side. The result will be that on each pumping stroke there will be a slight fiow past the check valve ball 164, the gas and/or liquid being delivered through tube MP8 to the discharge manifold. While the amount of this ilow will be a minor proportion of the entire discharge, because of the small size of the passages in valve lit-t9 as compared with those of Valves 43, it will serve to produce in each cycle a venting of any air or gas which may accumulate, tlie air or gas passing the valve more freely than the liquid. Thus the product chambers are maintained at all times essentially filled with the incompressible constituents of the product.

The overall operation is as follows:

Let it be assumed that at the beginning of a cycle the left hand pulsator in FIGURE 1 is receiving driving liquid while the right hand pulsator has its driving liquid space in communication with the discharge to the tank 2. The latter will be in the process of collapsing, and due to the tendency of the pulsator tube therein to return'to its rest position about its tube 56, the pressure on the supply of the product will cause the product to pass the inlet check valves and fill the right hand product chamber. The collapse of the right hand pulsator tube may be quite rapid so that this filling of the right hand pulsator by product may be rapidly accomplished and will represent an intermittent flow of the product into the pump. The discharge connection for the driving liquid to the right hand pulsator will then be closed and immediately thereafter communication to the driving liquid supply will be opend. This opening occurs prior to the closing of the driving liquid inlet connection to. the left hand pulsator, so that both may be receiving liquid simultaneously. (This may occur after a slight interval, in view of the check valve action described in my aforesaid Patent No. 2,836,121 which prevents interchange of driving liquid between the two pulsators to avoid a transient shock.)

The next event will be the closing of the left hand pulsator to the supply of driving liquid. This ends its pumping stroke. Thereafter the pulsator will be open to can provide discharge of driving liquid from its interior with resulting collapse of its pulsator tube. Thus the left hand pulsator will be filled with pumped liquid. The result of the operation is to provide, in view of the overlapping pumping actions of the pulsators, a continuous flow of the product as determined by the inflow of the driving liquid through connection 16. The cycle repeats in accordance with the reciprocatory movements of the valve members driven through connection 26 from motor 4. The concurrent actions of getting of any accumulations of solid materials at the lower ends of the pulsators and the venting of air or gases occur as described above.

it will be evident that various changes in details of the invention may be made without departing from its scope as defined in the following claims.

What is claimed is:

l. A pump comprising a cylinder having its axis extendupwardly, longitudinally extending ribs projecting radially inwardly from circumferentially spaced cylinder wall areas, an elastic cylindrical pulsator within said cylinder providing in its interior a driving liqud space and at ts exterior an annular pumped liquid space, means effecting intermittent introduction of driving liquid into said driving liquid space and discharge of driving liquid therefrom, and check valved inlet and outlet conduit means connected to the lowermost terminal portion of said cylinder and communicating with the annular pumped liquid space therein, said pulsator being in the form of a plurality of cylindrical sheets of rubber material bonded together to form an integral laminated structure having sufficient stiffness to collapse of its own resiliency to a definite cylindrical shape upon removal of driving liquid pressure from its interior and despite the existence of a acuurn at its exterior, said stilfness and the radial extentof said ribs being sufficient to prevent sealing of said pulsator against the wall of said cylinder.

2. A pump comprising a cylinder having its axis extending upwardly, an elastic cylindrical pulsator within said cylinder providing in its interior a drivng liqud space and at its exterior an annular pumped liquid space, means effecting intermittent introduction of driving liquid into said driving liquid space and discharge of driving liquid therefrom, valved inlet and outlet conduit means connected to the lowermost terminal portion of said cylinder and communicating with the annular pumped liquid space therein, and a check valve connected to the uppermost terminal portion of said cylinder and communicating with the annular pumped liquid space therein, said check valve being operative to open to vent gas from said pumped liquid space each time pressure is produced in said pumped liquid space.

3. A pump comprising a cylinder having its axis extending upwardly, an elastic cylindrical pulsator Within sm'd cylinder providing in its interior a driving liquid space and at its exterior an annular pumped liquid space, means effecting intermittent introduction of driving liquid into said driving liquid space and discharge of driving liquid therefrom, valved inlet and outlet conduit means connected to the lowermost terminal portion of said cylinder and communicating with the annular pumped liquid space therein, and a vent check valve connected to the uppermost terminal portion of said cylinder and communicating with the annular pumped liquid space therein, said vent check valve being operative to open slightly before said outlet means upon the production of pressure in said pumped liquid space to vent gas therefrom.

4. A pump comprising a cylinder having its axis extending upwardly, longitudinally extending ribs projecting radially inwardly from circumferentially spaced cylinder wall areas, an elastic cylindrical pulsator within said cylinder providing in its interior a driving liquid space and at its exterior an annular pumped liquid space, means effecting intermittent introduction of driving liquid into said driving liquid space and discharge of driving liquid therefrom, and check valved inlet and outlet conduit means connected to the lowermost terminal portion of said cylinder and communicating with the annular pumped liquid space therein, said pulsator having sufiicient stiffnessto collapse of its own resiliency to a definite cylindrical shape upon removal of driving liquid pressure from its interior and despite the existence of a vacuum at its exterior, said stiilness and the radial extent of said ribs being sufiicient to prevent sealing of said pulsator against the Wall of said cylinder.

5. A pump comprising a cylinder, an elastic pulsator Within said cylinder providing in its interior a driving liquid space and at its exterior a pumped liquid space, means intermittently introducing driving liquid into said driving liquid space to effect pumpin expansion of the pulsator and discharging driving liquid from said driving liquid space to collapse the pulsator, valved inlet and outlet conduit means connected to the lowermost terminal portion of said cylinder and communicating with the pumped liquid space therein, means providing a vent passage in said cylinder at the uppermost terminal portion of said pumped liquid space constructed and arranged for the slight escape of liquid and/or gas therefrom, and means normally closing said vent passage and responsive solely to each said pumping expansion of the pulsator to open said vent passage, thereby to permit said slight escape of liquid and/ or gas.

6. A pump according to claim 5, including conduit means connecting said vent passage to said outlet conduit for delivering said liquid and/ or gas thereto.

7. A pump according to claim 5, wherein the lastmentioned means is constructed and arranged to open said vent passage slightly before said outlet means is opened upon the production of pressure in said pumped liquid space.

8. A pump comprising a cylinder having its axis extending upwardly, an elastic cylindrical pulsator within said cylinder providing in its interior a driving liquid space and at its exterior an annular pumped liquid space, means effecting intermittent introduction of driving liquid into said driving liquid space and discharge of driving liquid therefrom, valved inlet and outlet conduit means connected to the lowermost terminal portion of said cylinder and communicating with the annular pumped liquid space therein, means providing a vent passage in said cylinder at the uppermost terminal portion of said pumped liquid space constructed and arranged for the slight escape of liquid and/or gas therefrom, and means normally closing said vent passage and responsive to a predetermined normal increase in pressure in said pumped liquid space, incidental to pumping expansions of the pulsator, to open said passage, thereby effecting said slight escape of liquid and/or gas.

9. A pump according to claim 8, including conduit means connecting said vent passage to said outlet conduit for delivering said liquid and/ or gas-thereto.

10. A pump according to claim 8, wherein the lastmentioned means is constructed and arranged to open said vent passage slightly before said outlet means is opened upon the production of pressure in said pumped liquid space.

References Cited in the tile or" this patent UNITED STATES PATENTS 885,835 Brush Apr. 28, 1908 1,389,635 Dunkle Sept. 6, 1921 1,803,191 Jennings Apr. 28, 1931 1,990,139 Scott Feb. 5, 1935 1,993,267 Ferguson Mar. 5, 1935 2,424,595 Warren July 29, 1947 2,444,586 Wuensch July 6, 1948 2,478,568 Coe Aug. 9, 1949 2,532,143 Breit Nov. 28, 1950 2,738,731 Browne Mar. 20, 1956 2,836,121 Browne May 27, 1958 2,898,866 Deackoi'l Aug. 11, 1959 FOREIGN PATENTS 7,285 Great Britain July 13, 1911 754,910 Great Britain Aug. 15, 1956

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