US3036525A - Chemical feed pump - Google Patents

Description

May 29, 1962 R. E. SCHULZE ET AL 3,036,525

CHEMICAL FEED PUMP Filed Deo. 16, 1959 2 Sheets-Sheet l May 29, 1952 R. E. scHuLzE ETAL 3,036,525

CHEMICAL FEED.PUMP

Filed Deo. 16, 1959 2 Sheets-Sheet 2 BL bk @www . www.

ii@ @amg 3,36,525 Patented May 29, 1962 mili 3,036,525 CHEMECAL FEED PUMP Robert E. Schulze, Deerield, lll., and Robert l. Jauch and Christian W. Kruckeberg, Fort Wayne, Ind., assignors to Culligan, inc., Northbrook, Ill., a corporation of Delaware Filed Dec. i6, 1959, Ser. No. 859,987 l Claims. (Cl. 10S-3S) The present invention relates to a novel construction and a nove-l manner of operation of a chemical feed pump for accurately proportioning and delivering small quantities of fluid under pressure.

Chemical feed pumps are used in many industries where small quantities of a chemical solution are fed at a predetermined xed rate to a conduit carrying liquid to be treated. These pumps generally carry liquids which are highly corrosive in nature, such as acids or alkalies, and are required to be metered in proper amounts to achieve the desired results.

Two prevalent uses for such chemical feed pumps are found in the water conditioning industry and in the food treatment industry with examples of use in the first industry including swimming pool chlorinators and fluorine and chlorine treatment of drinking water supply. ln such cases, deviations in the feeding rate of chlorine and fluorine solutions might produce undesirable consequences resulting from the use of the treated liquid,

In the past, two major types of chemical feeder pumps have been used; the plunger type and the diaphragm type. Both of these types have major disadvantages which the present invention overcomes. The plunger type pump is .generally quite accurate in proportioning fluids, but the pump plunger is in direct contact with the corrosive fluids being pumped. Further, a moving seal on the reciprocating plunger is required which becomes worn through use and permits leakage of the corrosive and hazardous fluids into the pump mechanism causing considerable damage.

The diaphragm type pump is in more common usage since no moving seals are present and corrosive uids do not have the opportunity to leak into the pumping mechanism. However, the diaphragm must be of a lexible material to compensate for movement and such ma- 'terial tends to deform under the alternate suction and pressure conditions necessary for the pumping operation. Such deformations or convolutions cause inaccuracy in proportioning of the tluid additives since variation in either suction or pressure conditions cause change in the diaphragm convolution which affect the discharge volume of the pump.

Various methods have been attempted to reduce the change in diaphragm deformation at different pumping pressures by inserting rigid materials within the structure of the diaphragm or by substantially increasing the thickness of the diaphragm. But either of these methods results in greatly reducing the pumping `life of the diaphragm and requires a substantially greater amount of power to operate.

One attempt to solve these problems was the use of a `diaphragm at the pressure chamber and a plunger behind the diaphragm. However, the space between the plunger and the diaphragm was filled with a liquid to ltransmit pressure from the plunger to the diaphragm and, if failure occurred in the diaphragm, the operating fluid would leak and contaminate the liquid being pumped; such contamination leading to undesirable and sometimes highly dangerous results where the liquid being pumped reacts with the operating fluid.

Among the objects of our invention is the provision for a new and novel chemical feed pump overcoming the disadvantages of prior pump designs` which includes a combination of a pumping plunger giving excellent accuracy over the entire pump pressure range and a diaphragm giving resistance to corrosion from hazardous luids.

Another important object is the provision of a very thin flexible diaphragm separating the lluid being pumped from the pumping mechanism, such diaphragm being vformed from highly resistant compounds capable of a long life and not subject to rapid failure from handling corrosive liquids or hazardous chemicals.

Another object of the present invention is the provision of a pump which does not require operating fluid in the chamber between the thin flexible diaphragm and the actuating plunger, the pump plunger being sealed by means of a second diaphragm which prevents any leakage of liquid being pumped into the chamber containing the pump operating mechanism.

The present invention further contemplates that the pumping plunger is not directly connected. to the pump diaphragm, but that the plunger fully and effectively supports the pumping diaphragm at the diaphragms forward position.

The present invention further contemplates a simplified construction and operation where the pumping diaphragm is reciprocated to its forward position by the pumping plunger and to its rearward position by a vacuum created inthe plunger chamber by retraction of the pumping plunger.

ln this novel assembly the plunger chamber is sealed at the near by a second and larger diaphragm which functions as a vacuum pump and also as a seal to prevent accidental leakage of pumping fluid into the pump mechanism in the event of failure of the forward or pumping diaphragm. A vacuum check valve and vent are provided for the plunger chamber with the vent expelling any air that may find its way into the plunger chamber and `also providing means for determining whether the forward diaphragm has failed.

It is, therefore, a further object to provide a vent to permit the escape of air in the plunger chamber and to act as an indicator to show uid leakage if there is a failure in the pumping diaphragm.

Another object of the present invention is to provide a feed pump having a fully adjustable control for accurately setting the pumping rate over the entire pumping range and to have a pump which is self-priming.

The present invention further comprehends a chemical feed pump having novel adjusting mechanism that accurately establishes the location of the pumping plunger and is provided with a simple locking feature which prevents any change during operation of the pump.

Further objects of the present invention include the provision of a chemical feed pump of maximum simplicity and ease of operation,'an economical unit and such other objects and inherent features :as will more fully appear in the following description and claims.

In the drawings:

FIGURE l is a top plan View of the pumping apparatus with portions broken away to show the internal structure of the pump and its control mechanism.

FlG. 2 is a vertical cross sectional view on line 2 2 of FIG. l and viewed in the direction of the arrows.

FIG. 3 is a disassembled view showing the component parts of an installation system of the pump to feed a chemical solution to a main supply line.

Referring particularly to the disclosure in the drawings and to the illustrative embodiment of the invention shown therein, the pump assembly il) comprises a pump housing il, a shroud l2 and a shroud cover 13 enclosing a gear head motor 25. The pump housing is provided with a recess 14 in which the motor is held by screws 15. The housing rests on feet 16 which are part of the casting for said housing. There is an opening 17 in the bottom of the housing covered by a removable plate 18 to permit access to the actuating unit for the pump, and an opening 19 in the top of the housing through which projects the drive shaft of the motor. At one end of the housing is attached a Cylinder head 20 which is attached to the housing by head studs 21 litting in holes 22 `with nuts '23 engaging the threaded ends of the studs 21.

The motor 25 is a small gear motor, the design of which forms no part of the present invention. The motor has a cooling fan 26 and a shaft 27 depending from the motor and extending through the opening 19 into chamber 28. A `cam or eccentric 31 is mounted on the motor shaft 27 by a pin 32. A cam roller 33 is mounted on and encompasses the cam 31 and held in place against lateral movement by spaced retaining rings 29.

In contact with the cam roller 33 is a tappet or headed stud 34 which is adjustably attached to a pump shaft 35 by a threaded shank 36. A retainer plate 37 is mounted on the tappet 34 and held in contact with the end of the pump shaft by a nut 38, which nut may also act as a lock nut for the tappet 34. The pump shaft 35 reciprocates in a shaft housing 39 and is held in proper position by and moves longitudinally through shaft bearings 40 at the opposite ends of the shaft housing. A spring 41 encompasses and is anchored at one end to the shaft housing 39 and abuts at the other end the retainer plate 37 carried `on and tending to force the pump shaft rearwardly and away from the cylinder head 20 on the return stroke.

On the forward end of pump shaft 35 is attached a back-up plate 42 and clamped between a pump plunger or piston 43 `and the back-up plate 42 is a suction diaphragm 44. The plunger 43 is attached to the shaft 35 by a threaded stud 45. This suction diaphragm 44 acts as a sealing element for the pump plunger and has its outer periphery clamped to the pump housing between a support plate 46 and a plunger cylinder 47. The plunger cylinder 47 has a centrally disposed chamber 48 in which the plunger 43 reciprocates.

Forward of the chamber 48 and clamped `between the cylinder 47 and the cylinder head 20 is a pumping diaphragm 49. Both of the diaphragms 44 and 49 in this pump are formed or compounded of a thin flexible material which is corrosion resistant. An example of such a diaphragm is a layer of Woven Daeron sandwiched between coatings of KEL-F (monochlorotriiluoroethylene) of equal thickness with the thickness of the Dacron layer. This pumping diaphragm 49 acts on uid in a chamber 5t) to force the fluid through the cylinder head land into the material being treated. The cylinder head is formed with a main passage 51 extending completely across the cylinder head 2G and a branch passage 52 from the main passage to the pressure chamber 56.

Cylinder head 20 is provided with three fittings 53, 6l and 65. Fitting 53 is the inlet suction fitting and is attached to head Ztl by external screw threads on the fitting with .a fitting gasket 54 held between the flange on the fitting 53 and the cylinder head '26. This fitting 53 has an inlet passage 55 arranged perpendicular to the main passage 51. A valve fitting 56 closes over the end of passage 51 adjacent the inlet passage 55 yand is provided with O-rings 57, 57a to prevent fluid leakage and contains `a non-return or check valve 53. On the suction or back stroke of the pump, the Huid passes through the inlet passage 55 and past the non-return valve 53 to the transverse main passage 51.

The second fitting 6l is the outlet fitting leading to the conduit through which flows the liquid to be treated. This fitting is provided with a check or non-return valve 58a and is also attached to the cylinder head Ztl by external screw threads on the fitting. A fitting gasket t 54 is also clamped between the fitting 6l and the head 20. This tting is provided with a 4tubing gland nut 62 and a tubing gland 63 to clamp the discharge tubing to the fitting and prevent it from collapsing. The check valves 53 ano 5Sa are constructed of a rigid material so as not to deflect under pressure.

The third fitting 65 is a discharge fitting for air and any fiuid leakage into chamber 43. Cylinder 47 is provided with a vent passage 66 and a non-return valve 67 with the passage from the non-return valve opening and leading to the fitting 65 for discharge to the atmosphere.

Referring to FIG. l, an adjustment control means is shown which accurately controls the rate of flow from the pumping unit. This control means includes a cam or eccentric 71 which limits the reciprocatory stroke of the pump plunger 43 as the back-up plate 42 contacts the cam '7l on the rearward stroke. The cam 71 is attached to the inner end of a rotatable shaft 72 by a pin 73. At the exterior end `of this shaft 72 is attached an adjustment knob 74 by means of a set screw 75. The shaft 72 rotates in an opening 76 in the pump housing 11 with this opening being reduced or shouldered at 77 and 78. Adjacent the cam 71, the inner end of the shaft rotates in a bearing 79 and seated on the stepped reduction 77 is a clutch ring 81 held in place by ring nut 82 threaded into the tapped opening 76. The shaft 72 carries a clutch cone S3 secured to the shaft by pin 84 with the clutch cone 83 biased into engagement with the clutch ring 81 by means of a coil spring 85 which has its opposite end seated on the stepped reduction 78. Knob 74 carries a dial plate 86 having indications -for calibration of the pump in gallons per hour to agree with any particular cam setting.

When the pump lit is installed in a plant, an installation such as shown in FIG. 3 disassembled and 4diagrammatically, may be used. '1t includes a storage tank 91 containing the uid to be metered into a supply line 103. A plastic tube 92 leads from a suction fitting 93 to the inlet fitting S3 on the cylinder head of thepump with this fitting 93 including a check valve 94 depending into the contents of the storage tank. A weight 95 made of a corrosive resistant material such as porcelain is shown fitted over the tube 92 above the suction fitting 93 to retain the fitting in the solution to be fed. A second plastic tube 96 leads from the outlet fitting 61 of the pump assembly to a discharge fitting 97. The discharge fitting includes a check valve 93, a tubing gland nut 99, a tubing gland and a nipple 101 entering a T joint 102 in the material supply line 103. If desired, a third plastic tube can be 'attached to the discharge fitting 65 leading to the storage tank.

In the `operation of the present novel chemical feed pump, the motor 25 is operated from `a suitable supply such as a ll() volt source of alternating current rotating the shaft 27 `and its cam 31. rPhe cam roller 33 is thereby forced against stud 34 to reciprocate the pump shaft 35 in `one direction with the spring 41 biasing the retainer plate 37 and causing the shaft `to return in the reverse direction whereby the cam roller and spring impart continuous reciprocating motion to the pump shaft. The plunger `or piston 43 on the reciprocating shaft is sealed by the suction diaphragm 44 which has a larger area than the area of the pumping diaphragm `49.

0n forward motion of the pump plunger 43 in cylinder 47, air trapped in the chamber 48 is expelled through the vent passage 66. On the return stroke, `a vacuum is created in the chamber 48 by the suction diaphragm 44 thus drawing the pumping diaphragm 49 into `the chamber 48, `and drawing liquid through the non-return valve 58 into the pressure chamber 50. On the next forward stroke, the plunger head 43 forces the pumping diaphragm 49 into the pressure chamber 50 forcing liquid to be dispensed from that chamber out through the discharge fitting 61. Then on each subsequent cycle, fluid is drawn into the cylinder head on the return stroke of the pump b shaft 35 and forced out -through the discharge fitting 61 on a forward stroke.

Referring to FIG. 3, Where the pumping unit is shown disassembled, to prime the pump the tube 96 is disconnected from discharge fitting 61, and the pump is primed by operating the pump with the suction fitting immersed in water. When the pump is primed, the tube 96 is connected to discharge fitting 61, the suction fitting 93 connected to the inlet fitting 53 is immersed in the solution in the tank 91 and the pump is put into operation.

To vary the discharge rate of the pump the adjustment knob 74 is changed while lthe pump is operating. To change the adjustment, the knob 7'4 is pushed inwardly or toward the front wall of the pump housing 11 whereby to disengage the clutch cone 83 from its encompassing clutch ring 81. Then the knob is rotated in either direction for rotating the cam 71 to its desired position. When the proper discharge rate is obtained, the knob 74 is released 'and the coil or compression spring 85 forces clutch cone 83 outwardly into engagement with the clutch ring 81 and thereby retaining the cam 71 in proper adjustment. The dial plate S6 is calibrated for ease of adjustment to the proper discharge rate.

On the first forward stroke, air entrapped in the void or chamber `48 between the piston 43 -and the cylinder 47 is forced out through the check valve 67, which is preferably of rubber. As the cam 31 `starts on the return stroke, the spring 41 through the spring retainer 37 returns the piston to its rearward position. With the check valve 67 closed, this movement creates a vacuum between the piston and the pumping diaphragm 49 causing this diaphragm to follow the piston rearwardly. As this suction takes place, :the vacuum created in the chamberl 50 of the cylinder head causes the check valve 58 to open and fill with the chemical solution entering through the suction or inlet iitting 53. The piston 43 -on its forward stroke causes the check valve 58 to close and the check valve 58a to open to the discharge line with the solution discharged through the discharge fitting 61. The quantity of liquid pumped is determined by the return stroke of the plunger which in turn establishes the rear or suction position of the pumping diaphragm 49.

The capacity of the pump is controlled through the adjustment knob 74. A slight inward pressure on this knob frees the friction-type clutch cone 83 from its clutch ring 81 and the cam 71 is rotated to a position that limits the return of the piston and shaft assembly with the backup plate 42 resting against the cam 71. Attached to the outer end of the cam shaft 72 is the dial plate 86 calibrated in gallons per hour to agree with any particular cam setting. After adjusting or positioning the cam 71 through the knob 74 and release of inward pressure on the latter, the spring 85 forces the clutch cone 83 back into friotional engagement With the clutch ring 81 to retain the cam setting.

This invention is particularly useful as Aa swimming pool chlorinator, in Water treatment installations for the control of hydrogen sulfide, iron, fluorine or chlorine in the water or for water softener regeneration plants, but is not limited thereto as other uses will be apparent to those skilled in the art.

While disclosing a specific embodiment of the invention, We do not wish to be limited by this disclosure, but claim all equivalents in lthe invention which are inherent in this disclosure and the `appended claims.

Having thus disclosed the invention, we claim:

l. A chemical feed pump for accurately proportioning and ydelivering small quantities of uids under pressure, comprising a pump Ahousing having a pumping chamber, an inlet and an outlet communicating with said pumping chamber, non-return valves located in said inlet and outlet, a flexible diaphragm located in said pumping chamber for dispensing fluid in laccurately controlled quantities, said diaphragm being secured along its periphery in said pump housing, a plunger chamber in said housing, a

plunger reciprocable in said housing and separate from said diaphragm, said plunger in its forward position abutting said diaphragm and extending with said diaphragm into said pumping chamber, said plunger chamber being substantially devoid of air to produce a vacuum between said plunger Iand said diaphragm, a second flexible diaphragm secured `in said housing and spaced from said first mentioned diaphragm, said second diaphragm being secured at the center thereof to the rear of said plunger and acting as a seal for said plunger chamber, `and means to reciprocate said plunger.

2. A chemical feed pump yas set forth in claim 1 in which lan air vent communicates with said plunger chamber and is provided with `a check valve to prevent entrance of air into said chamber.

3. A chemical feed pump for `accurately metering land dispensing `small quantities of chemical uids of a corrosive nature, comprising a pump housing, ian intermediate member clamped -to said housing and containing a central opening, a cylinder head clamped to said last mentioned member and having a central pumping chamber formed therein, la uid inlet and `a fluid outlet in said cylinder head communica-ting with said pumping chamber, said inlet and outlet each containing a non-return valve, a reciprocating plunger in said central opening in said intermediate member, `a diaphragm clamped along its periphery between said pump housing and said intermediate member, said diaphragm being secured at its central to said plunger, ya pumping diaphragm separate from said plunger and clamped along its periphery be tween said intermediate member and said cylinder head, and means to reciprocate said plunger, said plunger abutting said pumping diaphragm and forcing said diaphragm into said pumping chamber on its forward stroke and drawing said pumping ydiaphragm out of said pumping chamber by vacuum on its return stroke.

4. A chemical feed pump as set forth in claim 3, including an adjustable cam mounted in said pump housing behind and spaced rearwardly of said first mentioned diaphragm, said plunger Vabutting said cam on its return stroke to limit the return stroke, a shaft extending through a wall of said pump housing and axed at its inner end to said cam, a clutch mechanism for locking said shaft yand said cam in adjusted position, a manually actuated knob on the exterior of said pump housing iand mounted on the outer end of said shaft to rotate the shaft and yadjust said cam, and a calibrated dial on said knob.

5. A chemical feed pump comprising a pump housing operating mechanism in said housing including a drive motor having a drive shaft, a cam attached to said drive shaft, `a cam roller Ion said cam, la pump shaft and plunger reciprocated by said cam land roller, a spring biasing said shaft toward said cam roller, a cylinder having a chamber for receiving said plunger, a cylinder head having Ia cent-ral pumping chamber and an inlet and an outlet therefor, check valves for said inlet and outlet, said plunger chamber opening into said pumping chamber, a flexible pumping diaphragm separate from said plunger secured between said cylinder and cylinder head `and extending across the end of said plunger chamber, said plunger adapted to reciprocate into said pumping chamber and abut said pumping diaphragm during the forward plunger stroke.

6. A chemical feed pump as set forth in claim 5, in which a second flexible diaphragm spaced from said pumping diaphragm is secured along its periphery to the pump housing and at its center to said plunger and forming a seal for said plunger chamber.

7. A pump for laccurately metering small quantities of liquid under pressure, comprising =a pump housing, a plunger cylinder secured to said housing and having a central chamber, a pump plunger adapted to reciprocate in said chamber, drive means for reciprocating said pump plunger, a flexible sealing diaphragm clamped `along its periphery between said pump housing and said cylinder and at its center aiiixed to the plunger, yan air vent passage communicating with said chamber and provided with a check valve to allow air to escape from said chamber, a cylinder head secured to said cylinder and having a central pumping chamber, an inlet tting and a discharge fitting on said cylinder head, a passage connecting said inlet and outlet fittings and communicating with said pumping chamber, said plunger chamber opening into said pumping chamber, yand a flexible pumping diaphragm extending across the open end of said cylinder and secured along its periphery between said cylinder and said cylinder head, said iiexible diaphragm being separate from said plunger with said plunger moving into the pumping chamber on its forward stroke, expelling air from said plunger chamber and abutting and forcing said pumping diaphragm into said pumping chamber, and on its rearward stroke creating a vacuum -to draw the pumping diaphragm partially into said plunger cylinder.

8. A chemical feed pump for accurately metering small quantities of liquid under pressure, comprising a pump housing, Operating mechanism in said housing including a pump shaft and plunger reciprocated by said mechanism, a back-up plate secured to the rear of said plunger, a plunger cylinder having a chamber to receive said plunger, a cylinder head secured to said cylinder and pump housing, a central pumping chamber in said cylinder head and opening into said pumping chamber, said cylinder head having an inlet and an outlet each provided with a check valve, a passage connecting said inlet [and outlet and communicating with said pressure chamber, a vent leading from Said plunger chamber to discharge and provided with a check valve, a flexible sealing diaphragm having its periphery `clamped between said housing and said cylinder and its central portion clamped between said plunger and said backeup plate, said diaphragm closing off the rear of said plunger chamber, a iiexible pumping diaphragm extending across the front of said plunger cylinder and having its periphery clamped between said cylinder and said cylinder head, said pumping diaphragm being separate from but disposed adjacent said plunger, and means to vary the stroke of the plunger to adjust `the quantity of liquid discharged by said pump, whereby upon the forward stroke `of said plunger air entrapped within the plunger chamber is exhausted through the vent to discharge and said plunger abuts said pumping diaphragm and moves yit into `the pumping chamber -to discharge a quantity of vliquid from the pumping chamber, and as the plunger begins its return stroke the vent is closed by the check valve and the pumping diaphragm is drawn back into the plunger chamber by the vacuum created Itherein to draw liquid into said pumping chamber.

9. A chemical feed pump as set forth in claim 8, in which said means to adjust the discharge of liquid includes a cam in said pump housing for limiting the return stroke of said plunger by contact with said -back-up plate, a shaft secured to the cam and extending through said housing, a knob on the exterior of said housing secured to the shaft and adapted to rotate said shaft and cam, v

and means for locking said cam in its adjusted position.

l0. A chemical feed pump as set forth in claim 9, in which said cam locking means includes a clutch ring secured to said housing, a clutch cone secured to said shaft, and spring means longitudinally biasing said shaft to engage said clutch cone with said `clutch ring and lock said cam, adjustment of the cam being obtained by pushing the knob and shaft inward and turning to rotate said cam.

References Cited in the tile of this patent UNlTED STATES PATENTS 2,323,950 Wade July 13, 1943 2,346,964 Harper Apr. 18, 1944 2,732,069 Henderson Ian. 24, 1956 2,855,850 Morris Oct. 14, 1958 2,869,585 Baker Jan. 20, 1959

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