US2711134A - Chemical feeder - Google Patents

Description

June 21, 1955 Filed July 26, 1950 w. J. HUGHES 2,711,134

CHEMICAL FEEDER 2 Sheets-Sheet 1 INVENTOR.

eggs/zit June 21, 1955 w. J. HUGHES CHEMICAL FEEDER ZSheets-Sheet 2 Filed July 26, 1950 v HVVENTOR. Wazfew :[flgg/zes BY w CHEMICAL FEEDER Waiter 1. Hughes, Chicago, Ill., assignor to Infilco Incorporated, Chicago, 111., a corporation of Delaware Application July 26, 1950, Serial No. 176,000

6 Claims. (Cl. 103-38) It is an object of this invention to provide a chemical pump of this general type whose actual pumpage is linear to the predetermined displacement capacity of the pump at any setting of the stroke.

Another object of the invention is to provide a chemical pump having positive means for preventing pumpage beyond the predetermined displacement capacity.

Another object of the invention is to provide a pump diaphragm preformed in the shape it assumes at the end of its pressure stroke and which is subjected during the suction stroke to crimping rather than to stretching.

Another object of the invention is to provide a diaphragm pump where in the pumping diaphragm is prevented by positive means from being stretched beyond its molded shape.

A particular object of the invention is to improve the chemical solution feeder of my said copending application.

These and other objects of the invention will become apparent upon consideration of the detailed description and the claims which follow.

In pumps of the type referred to herein, where the number of strokes is quite high, inertia of the moving liquid in the pumping chamber and in the suction and discharge lines causes pumpage to take place beyond the set rate of displacement, unless the liquid flow is positively stopped at the end of each pump stroke. This is attained in the apparatus of the present invention by locating the inlet and outlet ports of the pumping chamber, and by forming the diaphragm, in such manner that the diaphragm, at the end of its pressure stroke, firmly covers the ports, thus utilizing the pumping diaphragm as a valve for the ports.

The invention will be more readily understood by reference to the drawings wherein:

Figure 1 is a vertical cross-sectional view of an apr paratus according to the invention showing the diaphragm on its pressure stroke;

Figure 2 is a partial vertical sectional view of the apparatus of Figure 1 showing the diaphragm in the 'retracted position atthe end of the suction stroke;

Figure 3 is a partial vertical sectional view diagrammatically showing the two end positions of the diaphragm, the position at the end of the suction stroke being shown in full lines and the position at the end of the pressure stroke in dotted lines;

Figure 4 is a side view of the diaphragm; and

Figure 5 is a plan view of the diaphragm.

For purposes of illustration the invention is shown incorporated in a pump similar to that of my said copending application; but it should be understood that the invention is not limited to the specific structural "nited States Patent 0 of thepumping chamber.

details of the embodiment shown, but can be used with other pressure fluid operated diaphragm pumps.

The pump 10 comprises a housing or body 11, a pump head 12, anda diaphragm 13 clamped between the housing and the head. The pump head 12 has a recessed portion forming a cylindrical pumping chamber 16 having a fiat end wall 17 and a side wall 18. The housing 11 has a recessed portion forming a cylindrical forcing chamber 21 having a flat end wall 22opposed to the end wall 17 of the pumping chamber, and a side wall 23. The forcing chamber 21 is in alignment with the pumping chamber 16 and separated therefrom by the diaphragm 13, which is clamped between the adjacent ends of the side walls 18 and 23. v

The diaphragm 13 is formed of resilient material, such as rubber or the like, and is preformed in the shape shown in Figure l, which it assumes at the end of its pressure stroke. The diaphragm has a central solid cylindrical portion with a flat front face, a rolling or stocking type loop portion 31 molded to the perimeter of the center portion 30, and an outer flange portion 32, forming a locking ring 33, for clamping the diaphragm between the side walls 18 and 23 of the pumping chamber 16 and the forcing chamber 21. The loop portion 31 of the diaphragm in its molded shape extends in the pumping direction, but is less deep than the center portion, so that the loop 31 does not contact the end wall 17 of the pumping chamber at the end of the pumping stroke. The depth of the outer part of the loop must be at least equal to the distance the diaphragm travels on its full suction stroke. The inner portion of the loop is in rolling engagement with the side of the center portion 30, and the outer portion of the loop is in rolling engagement with the side Wall 13 of the pumping. chamber. stroke the outer portion of theloop rolls uniformly inwardly off the wall 18 and on to the outer surface .of the center portion 30. At the end of the suction stroke the loop 31 is'still extended toward the end wall 17 The diaphragm is sufliciently stiff that the loop is not distorted bythe slight negative head needed to fill the pumping chamber 16 with fluid chemical upon the spring actuated suction stroke. Thus filling of the pumping chamber is always uniform.

Embedded in the center portion of the diaphragm i3 is a metal plate 35 to which a screw 36 is fastened. The screw 36 extends through the raised bumper portion 34 of the rear face of the diaphragm. A spacer dit is threaded on the screw 36 and extends through the end wall 22 of the forcing chamber 21 into a spring chamber 41 formed in the housing ll. A compression spring 45 encircles the spacer 40 and abuts the inner end of the spring chamber 41 at one of itsends.

The opposite end of the spring 45 abuts a disc or washer Y 46, secured to the spacer 40 as by a screw 47.

The forcing chamber 21 has an inlet for fluid under pressure for actuating the diaphragm on its pressure stroke. The inlet for pressure fluid may be connected to any suitable means, such as a motor operated valve, not shown, to alternately connect said pressure fluid inlet to a source of fluid under pressure and to atmosphere. On its suction stroke the diaphragm is moved by the spring 45 which must be strong enough to overcome the pressure difference between atmosphere in the forcing chamber and the slight vacuum in the pumping chamber and the resiliency of the diaphragm which tends to return to its molded shape.

The center portion 30 of the diaphragm 13 is sufficiently large to fill most of the cross-sectional area of the cylindrical pumping chamber 16. The center portion 30 serves as a closure for the inlet port 51 and the outlet port 52 of the pump and these ports are, therefore,

Patented June 21, 1955 During the suction larged annular end portion 56 which abuts a valve guide 57 at its inner end. The valve guide 57 is mounted in a shouldered end 58 of the pump head 12. The fitting and the valve guide 57 are secured to the pump head by any suitable means, such as the internally threaded "coupling 59 shown, having engagement with an outer shouldered portion of the fitting 55. The inner end of "the inlet passageway 60 through the inlet fitting 55 forms a valve seat 61. The annular seating surface of the valve seat 61 is convex and is adapted to be engaged by the outer edge of a concave inlet valve 62 of pliable material. The inlet valve 62 has a relatively thick central portion and is tapered toward the periphery. Pressure in the valve chamber 65 within the enlarged portion 56 due to pressure in the pumping chamber 16 will therefore firmly engage the outer pliable concave portion of the valve 62 with the convex portion of the seat 61 with a uniform sliding or wiping action. The valve chamber 65 is connected to the pumping chamber 16 by means of a conduit 66 and the inlet port 51. The construction of the outlet conduit 70, outlet valve chamber 75, and outlet valve 72 are the same as described with regard to the inlet connections except that the parts are reversed relative to the pumping chamber 16, so that pressure from the pumping chamber 16 acts in valve opening direction on the outlet valve 72. The outlet valve chamber 75 is connected to the pumping chamber 16 by a conduit 76 and the outlet port 52.

To accurately control the rate of displacement of the pump any suitable adjustable stop means may be used. One advantageous form of such means is described in detail in said copending application and is also shown herein for purposes of illustration. Briefly this stop means comprises a screw 36 threaded within a spacer 81 secured to the outer end of the housing 11. The screw is also feathered on a shaft 82 which may be journaled in a cap 83 secured to the spacer 81. The shaft 82 can be rotated by means of a disc 85 secured thereto, rotation of the shaft 82 moving the screw 30 with respect to the disc 85. Moving of the screw 80 inwardly limits the stroke of the diaphragm 13 by limiting the extent to which the spring 45 can expand, and thereby retract the diaphragm on the suction stroke. The disc 85 may be calibrated, as shown, and the pitch of the threads of the stop screw 8t) may be such that one revolution of the disc 85 moves the screw from its extreme inward position, corresponding to zero pumping of the diaphragm, to its extreme outward position, corresponding to maximum pumping of the diaphragm.

In operation, when the fluid pressure in the forcing chamber is released, the spring 45 moves the diaphragm 13 to its retracted position to accomplish the suction stroke, the length of the stroke being determined by the setting of the stop screw 86. The suction in the pumping chamber 16 due to the retracting of the diaphragm as well as external discharge head holds the outlet valve 72 closed, while the inlet valve 67 opens to admit liquid to the pumping chamber, inlet port 51 being open as soon as the diaphragm starts to retract. 'When the suction stroke is completed and fluid pressure is again applied to the rear face of the diaphragm 13 in the forcing chamber 21, pressure in the pumping chamber 16 due to the forward moving of the diaphragm closes the inlet valve 62 and opens the outlet valve 72 so that the predetermined amount of liquid is expelled from the pumping chamber. When the diaphragm 13 reaches the end of its pressure stroke, it firmly closes the inlet and outlet ports 51 and 52. This positively cuts off any further ingress of liquid to, or egress of liquid from, the pumping chamber 16 At the end of each pressure stroke liquid is trapped in the annular space around the center portion '39 of the diaphragm between the side wall 18 of the pumping chamber, the sides of the center portion 30 and the loop portion 31 of the diaphragm. This trapped non-compres- V sible liquid provides a positive stop to any further flexing of the loop portion by fluid pressure on the rear of the diaphragm and is thus an additional safeguard against overpumping.

Due to the fact that the diaphragm is molded in the v shape which it assumes at the end of the pressure stroke the resiliency of the diaphragm cooperates with the fluid pressure applied to its rear face in making a perfect contact with the end wall of the pumping chamber at the end of, each pressure stroke. With a diaphragm molded in its retracted shape, such a contact is much more ditficult as there is likely to be a lag due tothe resiliency of the material counteracting the fluid pressure. I It will be understood that it is of the essence ofthe invention that ports 51 and 52 are completely closed by the center part of the diaphragm at the end of each pressure stroke to provide an actual displacement of the pump linear to its set capacity. It will also be obvious that byeliminating stretching of the diaphragm beyond its molded shape on the pressure as well as on the suction stroke, the life of the diaphragm is considerably prolonged.

I claim: I

l. A chemical pump having a forcing chamber and a pumping chamber, a pumping diaphragm of resilient material separating said chambers, an inlet port into said V pumping chamber, an outlet port from said pumping chamber and means for alternately applying fluid pressure and atmospheric pressure in said forcing chamber .over 1 the entire rear face of said diaphragm, characterized in i that said pumping and forcing chambers are cylindrical, each having a flat end wall and a side wall, in that said diaphragm is of rubber-like material andhas a solidfl'at cylindrical center portion, a loop portion concentric with said center portion and an outer concentric flange portion 7 adapted to be clamped between the side walls of said forcing and pumping chambers, said center portion'p'ro truding beyond said loop portion toward the end wall of said pumping chamber and contacting said end wall at the end of each pressure stroke, saidloop portion extending toward said end wall of the pumping chamber in all positions of the diaphragm but remaining spaced therefrom when said center portion contacts said end wall, whereby liquid trapped between said end wal1 andssaid loop portion prevents further flexing of said loop portion,

the inside of said loop portion having rolling support on the periphery of said solid center portion and the outside 1 of said loop portion having rolling support on the cylin drical side wall of said pumping chamber, and in that said inlet port to and said outlet port from said pumping chamber are located in the end wall of said pumping chamber within the area covered by said center portion.

2. In a metering pump of the type specified, a pumping chamber and a forcing chamber separated by a diaphragm of rubber-like material having an integral cylindrical, center portion and a concentric roller portion around the 1 said center portion, the said roller portion extending toward and into the said pumping chamber, a spring in the said forcing chamber urging the said diaphragm to retract from the said pumping chamber, an adjustable stop'for limiting the retracting by the said spring, means for-apply ing a fluid pressure to the said forcing chamber for moving said diaphragm on its pressure stroke, the depth of said center portion relative to the depth of said pumping chamber being such that said center portion contacts the end wall of said pumping chamber at the end of each pressure stroke, and inlet and outlet ports in the end wall of said pumping chamber, said ports being within the area covered by the center portion of said diaphragm at the end of the pressure stroke, whereby said center portion co-acts with the said ports to positively terminate the displacement of fluid from the said pumping chamber at the end of each pressure stroke.

3. A chemical pump having a forcing chamber and a pumping chamber, a pumping diaphragm of resilient material separating said chambers, an inlet port into said pumping chamber, an outlet port from said pumping chamber and means for alternately applying fluid pressure and atmospheric pressure in said forcing chamber over the rear face of said diaphragm, characterized in that said pumping and forcing chambers are cylindrical, each having a flat end wall and a side wall, in that said pumping diaphragm has a solid flat cylindrical center portion, a loop portion concentric with said center portion, and an outer concentric flange portion adapted to be clamped between the side walls of said forcing and pumping chambers, the depth of said center portion relative to the depth of said pumping chamber being such that said center portion bears against the end wall of said pumping chamber at the end of each pressure stroke, said center portion retaining its shape during pumping without use of nonresilient supports despite the resiliency of its material, and in that said inlet port to, and said outlet port from, said pumping chamber are located in the end wall of said pumping chamber within the area covered by said center portion at the end of the pressure stroke.

4. In a chemical pump of the type including a forcing chamber and a pumping chamber, an inlet leading to the pumping chamber, an outlet leading from the pumping chamber, and means for alternately applying fluid pressure and atmospheric pressure in said forcing chamber, a pumping diaphragm of resilient rubber-like material preformed in the shape it assumes at the end of the pressure stroke, said diaphragm having an integral solid cylindrical center portion, a concentric loop portion, and an outer concentric flange portion adapted to be clamped between the side walls of the pressure and the forcing chambers, said loop portion in the preformed shape extending in pumping direction and being less deep than the center portion, the depth of said center portion relative to the depth of said pumping chamber being such that said center portion contacts the end wall of the pumping chamber at the end of each pressure stroke, a spring secured to said diaphragm and urging said diaphragm into said forcing chamber, and an inlet port and an outlet port associated with said inlet and outlet, respectively, said ports being located in said end wall of the pumping chamber within the area covered by said center portion of the diaphragm at the end of its pressure stroke.

5. A chemical pump of the type including a forcing chamber and a pumping chamber, a pumping diaphragm of resilient rubber-like material separating said chambers, said pumping chamber having an inlet port and an outlet port, means for alternately applying fluid pressure and atmospheric pressure in the forcing chamber, and means for adjusting thetlength of the stroke of said diaphragm,

' front face and a loop portion concentric with said center portion, in that said pumping chamber has a flat end wall, said inlet and outlet ports being located in said end wall, in that the depth of said center portion relative to the depth of said pumping chamber is such that the front face of said center portion contacts said end wall at the end of each pressure stroke, whereby said ports are positively closed at the end of each pressure stroke, in that said loop portion extends toward said end wall in all operating positions of said diaphragm and is of less depth than said center portion to provide clearance between said loop portion and said end wall at the end of each pressure stroke, and in that a spring is connected to said diaphragm and urges said diaphragm toward said forcing chamber.

6. A chemical pump having a forcing chamber and a pumping chamber separated by a pumping diaphragm of resilient material, inlet means leading to said pumping chamber, outlet means leading from said pumping chamber, means for alternately applying fluid pressure and atmospheric pressure in said forcing chamber, and means for adjusting the length of stroke of said diaphragm, characterized in that said pumping chamber is cylindrical and t has a flat 'end wall, said inlet means including an inlet port in said end wall and said outlet means including an outlet port in said end wall, in that said diaphragm has an integral cylindrical center portion with a flat front face, a loop portion concentric with said center portion, and an outer clamping portion, said diaphragm being molded in the shape it assumes at the end of its pressure stroke, the depth of said center portion relative to the depth of said pumping chamber being such that the front face of said center portion contacts said end wall at the end of each pressure stroke, and said loop portion being shaped to extend toward, but to be spaced from, said end wall in all operating positions of said diaphragm, and in that the suction stroke of said diaphragm is accomplished by a spring urging said diaphragm toward the forcing chamber with sufficient force to overcome the difierence between atmospheric pressure in the forcing chamber 821,926 Cornish May 29, 1906 1,301,485 Mueller Apr. 22, 1919 1,372,943 Constantinesco Mar. 29, 1921 1,447,074 Gorman Feb. 27, 1923 1,982,966 Schweisthal Dec. 4, 1934 2,130,521 Brunner Sept. 20, 1938 2,145,566 Corydon et al Jan. 31, 1939 2,157,970 Rowland et al May 9, 1939 2,183,421 Brady Dec. 12, 1939 2,185,784 Corydon et al. Jan. 2, 1940 2,506,434 Quimper May 2, 1950 2,638,849 Budlane May 19, 1953 2,675,758 Hughes Apr. 20, 1954

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