US3314372A

US3314372A - Pump

Info

Publication number: US3314372A
Application number: US386863A
Authority: US
Inventors: Sutton Mack
Original assignee: Standard Oil Co
Current assignee: Standard Oil Co
Priority date: 1964-08-03
Filing date: 1964-08-03
Publication date: 1967-04-18
Anticipated expiration: 1984-04-18

Description

April 18, 1967 M. SUTTON 3,314,372

PUMP

Filed Aug. 5, 1964 Hydrau //'c INVENTOR Mac/r Sutton United States Patent ""ce 3,314,372 PUMP Mack Sutton, Louisville, Ky., assignor to Standard Oil Company, Chicago, Ill., a corporation of Indiana Filed Aug. 3, 1964, Ser. No. 386,863

2 Claims. (Cl. 103-153) This invention relates to a mean for pumping solidliquid slurries wherein the solids have a higher density than the slurrying liquid. More particularly, it relates to a means for pumping catalyst slurries.

One of the problems which has existed through the ages has been the problem of moving solid materials from one place to another. Among the solutions to this problem has been the formulation of a slurry of the particular solid to be moved and the transfer of that slurry through a length of pipe. Various methods have been employed in moving slurries through lines, but most of them have proven ineffective. This is particularly true in the case of small-scale equipment that is used in the laboratory and pilot plants, where often the transferring of specified quantities of a particular solid from one place to another is desired. Various pumps have been designed to move slurries through lines in such cases. These have failed to do the job for one reason or another. For example, solid particles in the slurry have become imbedded between the valve stems and associated seats in the pumps and have prevented the pumps for operating as they should. Furthermore, delicate parts of the pump have been quickly abraded and galled, resulting in the failure of the pump to function properly. In addition, the solid materials have settled from the slurries and plugged the various lines and passages through which they are to travel.

My invention overcomes the various difliculties which have been encountered in the moving of slurries in lines from one point to another. It is essentially a precision metering pump and has a particularly useful application in the moving of small quantities of slurries, which contain as much as -30% solids, in the laboratory and in pilot plants. It is also applicable in large-scale equipment. It is designed so as to take advantage of the settling of the solids from the slurry, rather than have this phenomenon destroy its operation.

Briefly, my apparatus for pumping slurries comprises, in combination, a plunger, an associated plunger chamber, a means for moving the plunger, a pumping chamber, a suction or inlet valve and a discharge or outlet valve. The two valves are similar, having a specially-designed stem. The means for moving the plunger is a piece of reciprocating equipment, such as a hydraulically-operated piston. Through theme of appropriate instrumentation, the plunger and valves are operated in a predetermined sequence so that the slurry to be pumped will be drawn into the pumping chamber followed by a subsequent ejection of the trapped slurry from the pumping chamber while backup of the material being pumped, as well as material that may-be found in the system into which the slurry is being transferred, is prevented.

My invention can be more easily understood through the use of the attached figures. FIGURE 1 is a diagram of the complete pumping apparatus. FIGURE 2 shows either of the valves that are used in the pumping apparatus in the open position. FIGURE 3 shows how the valve would appear when in the closed position.

As shown in FIGURE 1, the slurry to be pumped is introduced from line 1 through valve 2 into pumping chamber 3. The trapped slurry is then released from the pumping chamber 3 through valve 4 into line 5. Plunger 6 moves in a reciprocating manner in plunger chamber 7 and is fixedly connected to a conventional hydraulically-driven piston 8. A seal is made between the 3,314,372 Patented Apr. 18,1967

plunger 6 and the plunger chamber 7 in stufling box 9 by means of the square-shaped Teflon braided packing 10. There need be no void annular space between the plunger 6 and the side walls of plunger chamber 7. The pumping apparatus comprises, in combination,'suction valve 2, pumping chamber 3, plunger 6, plunger chamber 7, connection 3a between pumping chamber 3 and plunger cham: ber 7, hydraulically-driven piston 8 and discharge valve 4. The pumping chamber and plunger chamber are connected so that liquid may pass freely from one into the other. The various parts of this pumping apparatus are controlled by a system of appropriate instrumentation, which is known and easily understood by those skilled in the art.

At the start of the upstroke of plunger 6, both valves 2 and 4 are closed. A hydraulic fluid, such as a typical hydraulic oil, is introduced into the piston chamber 11 through line 12 below the head of piston 8 to drive the piston 8 upward. Air could be used to drive the piston 8. However, the compressibility of air would tend to promote inaccurate pumping. When the pressure in the pumping chamber 3 has been reduced below that which is found in line 1, quick-opening valve 2 opens and slurry flows into pumping chamber 3. At the top of the upstroke of the plunger 6, the desired quantity of slurry has been introduced into the pumping chamber, and valve 2 quickly closes. The hydraulic fluid is now introduced into the piston chamber 11 through line 13 above the head of piston 8 to force piston 8 and its associated plunger 6 downward. When the pressure in pumping chamber 3 becomes greater than the pressure in line 5, which is the same as the pressure in the vessel into which the slurry is to be pumped, valve 4 is quickly opened and the slurry is forced out of pumping chamber 3 through valve 4 and line 5 into the vessel (not shown). bottom of the downstroke of the plunger 6, valve 4 is closed and the hydraulic fluid is introduced through line 12 to the bottom side of the head of piston 8 and the cycle is repeated. The amount of slurry that is to be introduced into the pumping chamber is proportional to the size of plunger 6 and the length of the stroke of plunger 6. The time that is needed for one upstroke to be completed is dictated by the settling rate of the solid particles from the slurry. When the plunger has reached the top of its upstroke, most of the solid material should have settled from the liquid. Furthermore, the crosssection and length of the connection between the pumping chamber 3 and the plunger chamber 7 and the volume being swept out by the plunger 6 as it moves upward are correlated so that little or no solids are drawn out of the pumping chamber.

If any gas or vapor becomes trapped in the pumping chamber 3 or the plunger chamber 7, this gas or vapor can be removed from the system through the outlet 14-. which is bored along the longitudinal axis of plunger 6, and the associated line 15 and valve 16. 7

Both of the quick-opening valves 2 and 4 have especially-designed stems which are shown in FIGURE 2. The two valves are alike, the stem of each is made up of'three segments, a first means for moving a bottom segment along the longitudinal axis of the seat and into contact with the seat, and a second means adapted to move a top segment into contact with the seat. In this embodiment, the first means is an inner rod 22, and the second means is an outer rod 23. The bottom two segments of stem 17, segment 18 and segment 19, are tapered such that the extension of the outer surface of the bottom segment 18 coincides with the outer surface of the middle segment 19. The outer surface of the top segment 20 lies slightly inside the extension of the outer surface of bottom segment 18. ,All three segments of stem 17 and the seat 21 have the same angle of taper,

At the which is sufficiently great to prevent the solids from hanging up on these surfaces. All parts of the stem are fabricated from a metal except the middle section 19, which is fabricated from an elastomer. An elastomer is a suitable material for this segment as it can be easily deformed under stress and yet will regain its original shape when the applied stress has been removed. The associated seat 21 of the valve is fabricated from a metal, which could be the same metal as the stem. Materials are selected for this valve so as to be compatible with the chemicals that will be passed through the valve. The elastomer that is used in the fabrication of section 19 of the stem could be Viton, a compound which does not lose its properties at temperatures as high as 500- 600" F. The outer rod 23 of stem 17 is concentricwith the inner rod 22. The inner rod 22 has two diameters, the smaller of the two being at the lower end of the rod. The inner rod 22 is inserted through holes at the center of each of the three sections of stem 17. The hole of the bottom section 18 and the bottom of the inner rod are tapped so that the bottom section 18 is screwed onto the inner rod 22. In addition, a pin 24 is driven through both the bottom section, 18 and inner rod 22 to prevent turning of section 18 relative to rod 22. The top section of stem 17 has its center hole made of two diameters, the lower portion being that which will permit only the smaller diameter of rod 22 to pass through it, and a larger diameter at its upper portion which will permit the larger diameter ofrod 22 to pass through it. The center hole of middle section 19 and the smaller center hole of top section 20 are equivalent in diameter. The hollowed-out portion of the larger outer rod 23 is sufliciently long to permit vertical move ment .of the outer rod 23 when the inner rod 22 is in a fixed position and the outer rod 23 is being moved toward seat 21, which occurs as the valve is closed.

When either of the two valves, valve 2 or valve 4, closes, the entire assembly of stem 17 moves toward .seat 21. In the idea-1 case, that is, when no solid particles are trapped in between the stern and seat, the bottom two segments make contact with seat 21 and a seal is completed. In such a case, the top segment 20 will not contact seat 21; However, when a particle or particles of the abrasive solid are trapped between segment 18, segment 19, or both segments, and seat 21, bottom segment 18 does not make contact with seat 21. The top segment 20 continues to move toward seat 21 which causes the middle segment 19 to deform. The deformed middle segment 19 will contact seat 21 somewhere along its surface as shown in FIGURE 3. Trapped

solid particles

27, 28 and 29 are shown

betweenthe segments

18 and 19 and seat 21. Therefore, any solid particles of the slurry that have been trapped between

segments

18 and 19 and seat 21 will not prevent the flexible segment 19 from completing a seal. As rod 23 and top segment 20 continue their motion toward seat 21, the surface of segment 20 will contact the surface of seat 21 unless additional particles of solid'have become trapped between the surfaces of segment 20 and seat 21. Although particles of solids from theslurry are trapped between the metallic segments of stem 17 and seat 21, the complete seal provided by the elastomer segment 19 will enable the valve to close so that my invention Will operate properly. When the valve is to be opened, outer rod 23 and its attached segment 20 will begin to move away from seat 21. As segment 20 moves further away from seat 21, the flexible segment 19 will also be pulled away from seat 21 and will regain its original shape. The enlarged portion of rod 22 will be engaged firmly against the ledge 26 found in the center hole of segment 20. Segment 20 continues to move away from seat 21,

segments

18 and 19 will be moved with segment 20 and the valve will be returned to its completely opened position.

The operation of this pumping apparatus is so regulated that as the plunger is moving on its upstroke, the suction valve 2 will quickly open when the pressure in the pumping chamber 3 becomes less than the pressure that exists in the inlet line 1, which is the pressure of the system from which the slurry is being fed. As the plunger continues on its upstroke, slurry is drawn into the pumping chamber 2 up to an amount that has been established by the length of the stroke of the plunger 6 and the size of plunger 6. The time that is required for the plunger to complete its upstroke must be greater than the time that is needed for the solids to settle from the slurry, that is, the settling rate of thesolidsmust be faster than the rate of travel of the plunger. When the plunger reaches the top of its upstroke, suction valve 2 quickly closes and the plunger is subsequently made to start on its, downstroke so that the pressure may be built up within the pumping chamber 3. When the pressure in this chamber 3 attains a predetermined value, one which must exceed the value of the pressure existing in the system into whichthe slurry is to be discharged, the outlet valve 4 is opened and the slurry that is trapped in the chamber 3 is forced out of this chamber through valve 4 into the system to which this pump is connected.

The pumping apparatus is so put together that there is downfiow of the slurry as it passes fromvalve 2 through the pumpingcha-mber 3 into valve 4. Thepumping chamher is so designed and the pumping chamber and valves are so relatively located to one another that the slurry is introduced into the chamber at a high point in the chamber and removed from the chamber at its lowest point. Consequently, the inlet valve is connected to the chamber near its top andthe outlet valve is connected to the chamber near its bottom point. As theplunger 6 is moving in its upstroke and as it is moving in the initial part of its downstroke, the solid material in the slurry that has been drawn into the pumping chamber 3 settles out of the slurry. Due to the relative positioning of the two' valves and the pumping chamber, the solid material collects at the lowest point in the pumping chamber, which is adjacent to valve 4. Therefore, when .the outlet valve 4 is quickly opened, the solid particles which have collected at its entrance are immediately forced through the valve 4 into discharge line 5. This discharge of solid particles is immediately followed by the liquid .of the trapped slurry which flushes out the lower portion of the pumping chamber 3 and the valve 4, freeing 'these areas of any solid particles which may have adhered to their respective surfaces.

A model of this pumping apparatus has been used to pump a catalyst slurry into a polyolefin polymerization reactor. The pumping was performed at temperatures which normally be found in the range associated with room temperature, i.e., about 2 2. C. to about 28 C. In one trial the slurry contained about 20% solids; in another, about 30% solids. In each case, the solids of the slurry were particles of a fluidized molybdena-alumina catalyst. For the most part, the particle size of this catalyst ranged from about 5 microns to about microns. The liquid used in the slurry was odorless mineral spirits; The density of the catalyst particles was about 7 times the density of the liquid. The settling rate of the solids from the slurry was approximately 6 inches per minute. The elastomer section of the valve stem of each of the inlet and outlet valves was fabricated from Teflon rather than from an elastomer. Although Teflon is not as flexible as an elastomer, there appeared to be no failure or improper functioning of the apparatus as a result of faulty valve operation. In each case, the slurry was pumped into a reactor which was being operated at a pressure in excess'of 1000 p.s.i.g. The valves were modified Hammel- Dahl valves. The angles of the faces of the stem and seat in each valve were 75 T angles having the horizontal as a base. The relatively high pressure did not appear to prohibit the efficient operation of my pumping apparatus.

The embodiment of my invention that is described is in no way presented to limit the scope of my invention. The materials that must be used in the construction of the valves, pumping chamber, plunger chamber and plunger will be dictated by the type of material that is to be pumped with my apparatus and by the temperature at which the apparatus is to be used. If an elastomer, such as Viton, is employed, the apparatus can be used at a temperature as high as 500 F. without any appreciable difficulties. If those parts of the apparatus, which contain the parts that are fabricated from this elastomer, are eXternally cooled, it is possible for the apparatus to be used to pump slurries at temperatures that approach 600 F.

What I claim is:

1. An apparatus for the pumping or" a solid-liquid slurry, said apparatus comprising, in combination, a vertical reciprocating plunger, a plunger chamber for housing said plunger, first means for moving said plunger vertically in a reciprocating motion, said first means being fixedly connected to the top of said plunger and being located directly above said plunger, a pumping chamber having an inlet end and an outlet end, said outlet end being positioned at the lowest point of said pumping chamber, said pumping chamber being located below said plunger chamber and being connected thereto for the free passage of liquids therebetween and being positioned at an angle which places its outlet end below its inlet end at a distance which is sufficient to cause the settling of solids from the slurry to a point adjacent to its outlet end, second means for connecting said pumping chamber to said plunger chamber, the cross section and length of said second means and the volume being swept out by said plunger being correlated so that little or no solids are drawn out of said pumping chamber into said plunger chamber, an inlet valve connected to the upper end of said pumping chamber and adapted to regulate the flow of said slurry into said pumping chamber, and an outlet valve connected to the lower end of said pumping chamber and adapted to regulate the fiow of said slurry out of said pumping chamber, said valves being adapted to close completely, the positioning of said inlet valve, pumping chamber and outlet valve in relation to one another being such as to enable the solid 5 material in the slurry that is confined within said pumping chamber to settle from the liquid to said point in said pumping chamber adjacent to said outlet valve, the operations of said plunger and said inlet valve and said outlet valve being controlled to effectively move the slurry into and out of said pumping chamber.

2. Apparatus of claim 1 wherein said inlet valve and said outlet valve are each a valve adapted for the pumping of solid-liquid slurries which comprise a tapered seat and a stem, said stem comprising a bottom segment, a middle segment, the outer surface of which coincides substantially with the extension of the outer surface of said bottom segment, and a top segment, the outer surface of which lies slightly inside the extension of the outer surface of said bottom segment, said middle segment being disposed between said top and bottom segments, said bottom segments being substantially nondeformable and said middle segment comprising a deformable elastomer, first means for moving said bottom segment along the longitudinal axis of said seat and into contact with said seat, and second means adapted to move said top segment into contact with said seat, said second means being adapted to continue the movement of said top segment after said bottom segment has been seated, whereby said middle segment is slightly deformed and forms a seal against said seat.

References fitted by the Examiner UNlTED STATES PATENTS 2,017,974 10/1935 Kastner 10 3-453 2,151,514 3/1939 Heinen 103153 3,211,418 10/1965 Klinger et al. 251-187 FOREIGN PATENTS 524,395 12/ 1953 Belgium. 835,440 9/1938 France.

27,909 1908 Great Britain. 915,063 1/1963 Great Britain.

DONLEY J. STOCKING, Primary Examiner.

HENRY F. RADUAZO, MARK NEWMAN,

Examiners.

Claims

1. AN APPARATUS FOR THE PUMPING OF A SOLID-LIQUID SLURRY, SAID APPARATUS COMPRISING, IN COMBINATION, A VERTICAL RECIPROCATING PLUNGER, A PLUNGER CHAMBER FOR HOUSING SAID PLUNGER, FIRST MEANS FOR MOVING SAID PLUNGER VERTICALLY IN A RECIPROCATING MOTION, SAID FIRST MEANS BEING FIXEDLY CONNECTED TO THE TOP OF SAID PLUNGER AND BEING LOCATED DIRECTLY ABOVE SAID PLUNGER, A PUMPING CHAMBER HAVING AN INLET END AND AN OUTLET END, SAID OUTLET END BEING POSITIONED AT THE LOWEST POINT OF SAID PUMPING CHAMBER, SAID PUMPING CHAMBER BEING LOCATED BELOW SAID PLUNGER CHAMBER AND BEING CONNECTED THERETO FOR THE FREE PASSAGE OF LIQUIDS THEREBETWEEN AND BEING POSITIONED AT AN ANGLE WHICH PLACES ITS OUTLET END BELOW ITS INLET END AT A DISTANCE WHICH IS SUFFICIENT TO CAUSE THE SETTLING OF SOLIDS FROM THE SLURRY TO A POINT ADJACENT TO ITS OUTLET END, SECOND MEANS FOR CONNECTING SAID PUMPING CHAMBER TO SAID PLUNGER CHAMBER, THE CROSS SECTION AND LENGTH OF SAID SECOND MEANS AND THE VOLUME BEING SWEPT OUT BY SAID PLUNGER BEING CORRELATED SO THAT LITTLE OR NO SOLIDS ARE DRAWN OUT OF SAID PUMPING CHAMBER INTO SAID PLUNGER CHAMBER, AN INLET VALVE CONNECTED TO THE UPPER END OF SAID PUMPING CHAMBER AND ADAPTED TO REGULATE THE FLOW OF SAID SLURRY INTO SAID PUMPING CHAMBER, AND AN OUTLET VALVE CONNECTED TO THE LOWER END OF SAID PUMPING CHAMBER AND ADAPTED TO REGULATE THE FLOW OF SAID SLURRY OUT OF SAID PUMPING CHAMBER, SAID VALVES BEING ADAPTED TO CLOSE COMPLETELY, THE POSITIONING OF SAID INLET VALVE, PUMPING CHAMBER AND OUTLET VALVE IN RELATION TO ONE ANOTHER BEING SUCH AS TO ENABLE THE SOLID MATERIAL IN THE SLURRY THAT IS CONFINED WITHIN SAID PUMPING CHAMBER TO SETTLE FROM THE LIQUID TO SAID POINT IN SAID PUMPING CHAMBER ADJACENT TO SAID OUTLET VALVE, THE OPERATIONS OF SAID PLUNGER AND SAID INLET VALVE AND SAID OUTLET VALVE BEING CONTROLLED TO EFFECTIVELY MOVE THE SLURRY INTO AND OUT OF SAID PUMPING CHAMBER.