US3463094A - Pump and storage chambers for preventing back siphonage - Google Patents

Description

Aug. 26, 1969 ,1. R. FONDA 3,463,094

PUMP AND STORAGE CHAMBERS FOR PREVENTING BACK SIPHONAGE Filed May 5. 1968 s Sheets-Sheet 1 INVENTOR JOHN R. FONDA BY g kiu i fall ATTORNEYS Aug. 26, 1969 J. R. FONDA PUMP AND STORAGE CHAMBERS FOR PREVENTING BACK SIPHONAGE Filed May '3, 1968 5 Sheets-Sheet 2 FIG.6

INVENTOR JOHN R. FONDA BY 6M4 M/K ATTORNEYS Aug? 6, 1969 J. R. FONDA 3,463,094

PUMP AND STORAGE CHAMBERS FOR PREVENTING BACK SIPHONAGE Filed May :3. 1968 5 Sheets-Sheet 5 FIG-8 FIG? INVENTOR JOHN R. FONDA BY r/7M, {5406- ATTORNEYS United States Patent Office 3,463,094 Patented Aug. 26, 1969 3,463,094 PUMP AND STORAGE CHAMBERS FOR PREVENTING BACK SIPHONAGE John R. Fonda, 150 Victor Ave., Birmingham, Mich. 48203 Filed May 3, 1968, Ser. No. 726,292 Int. Cl. F04b 21/04; F161 43/00; B6711 /40 U.S. Cl. 103195 3 Claims ABSTRACT OF THE DISCLOSURE The pump of this invention comprises two axially aligned pistons, one controlling intake of fluid from a reservoir, and the other controlling its discharge through the pump outlet. Intermediate these stations are two storage chambers which function to assure accurate metering of the fluid and to prevent back siphonage of the fluid to the pump output in the event of loss of head at the output.

This invention relates to positive displacement pumps especially for use in water treatment systems.

Objects and summary of invention The unique pump of this invention is intended for use in a water treatment system, although it could be used in any application where its features would be similarly advantageous. Such a water treatment system, which is de scribed in detail in prior United States Patent No. 2,530,682 and No. 3,213,215, generally comprises a solenoid-actuated fluid pump which injects water treatment chemicals into a water system in response to electric impulses initiated by a water meter actuated switch. Such a system thus assures accurate and uniform regulation of the chemical dosage by making the pump output directly proportional to the volume of water flow as measured by the water meter. Such systems are frequently employed in large oflice or apartment buildings and the like to control rust and scale formation in the buildings water pipes.

In a pump for this purpose, there are several features which are essential to its proper operation. First, the discharge rate must be uniformly and accurately controlled, to assure even distribution of the chemical in the water and to positively preclude any excessive dosages which would contaminate the drinking water within the building in violation of local and federal drinking water standards.

Secondly, it is essential that back siphonage be positively prevented so as to comply with federal and municipal regulations which prohibit pumps for this purpose which would permit chemical to be siphoned backward from the building out into the municipal water system in the event of a loss of pressure head on the discharge side of the pump.

Still another essential feature of such a pump is that there be thorough sealing of the fluid chambers to prevent contamination of the chemical with lubricating oil from the oil bath in which the pump is submerged and contamination of the oil by the chemical.

It is also desirable that the output rate of the pump be easily and accurately adjustable when desired so as to assure proper chemical dosage.

These and other objects and advantages of the invention will become apparent from the following specification and drawings.

Brief description of the drawings FIG. 1 is a perspective view of the pump of this invention, with the oil well casing partially broken away to reveal the lower portion of the pump.

FIG. 2 is an exploded sectioned elevation of the upper and lower pump bodies and the distribution plate, the section being cut along the center line of this subassembly.

FIG. 3 is an elevation, partly in section, of the plunger assembly.

FIG. 4 is a perspective view of the upper portion of the lower piston.

FIG. 5 is a bottom view of the lower face of the upper body, viewed in the direction of arrows 5 5 of FIG. 2.

FIG. 6 is a bottom view of the distribution plate, viewed in the direction of arrows 6-6 of FIG. 2.

FIG. 7 is an elevation, partly in section and partly in schematic form, of the pump during the downward stroke of the plunger assembly.

FIG. 8 is a view similar to FIG. 7, but showing the condition of the pump during the upward stroke of the plunger assembly.

Detailed description of the structure Referring to FIGS. 1 and 2 in particular, the improved pump of this invention generally comprises a pump assembly 10 which is supported on the rim of oil well casing 12 so that the lower portion of the pump is submerged in an oil bath. The pump itself generally comprises upper and lower bodies 14 and 16, respectively, between which is sandwiched a distribution plate 18. These three components, as well as others to be described below, would be assembled with appropriate gaskets and connecting means such as screws, some of which are omitted from the drawings for purposes of simplicity and clarity of illustration.

A plunger assembly 10 (FIGS. 1 and 3) reciprocates within the pump bodies and distribution plate under the influence of actuator rod 22 and rocker arm 24, the latter being mounted on post 26 at pin 28.

Storage chamber 30 is mounted in upper body 14 and is provided with overflow tube 32 and atmospheric vent 34. A vertical passage 36 in upper body 14- provides communication between storage chamber 30 and the bottom face of the body.

Upper piston housing 38 is integrally formed with upper body 14 and has a central vertical bore 40 in which slides the plunger assembly described below. The upper end of the piston housing is provided with discharge port 42 and would be connected to a suitable pump discharge conduit leading to the building water supply system.

Also mounted in upper body 14 is a transparent cylindrical vacuum sealed sight glass 44 which functions as a second storage chamber and communicates with the lower face of body 14 by means of passage 46. A conduit 48 connects the upper portion of the sight glass chamber with a port 50 in the upper body casting 14 (see FIG. 5)

Storage chamber 30 and sight glass 44 may be secured, for example, in upper body 14 by a top plate and a screw passing downwardly through such chamber into the body. These have been omitted from the drawings for clarity.

Distribution plate 18 (FIGS. 2 and 6) is provided with four ports and two communicating passages. Port 52 aligns with storage chamber port 36 of the upper body 14, while hole 54 aligns with the upper piston housing bore 40. Port 56 communicates with sight glass port 46, and port 58 aligns with sight glass conduit port 50. Ports 52 and 58 are interconnected by a transverse connecting channel 60, while ports 54 and 56 are similarly connected by channel 62.

Inlet channel 64 of lower body 16 (FIG. 2) is connected to pump suction tube 66 (FIG. 1) which has a double U configuration and terminates in a filter 68 which would be submerged in a reservoir outside of the oil well 12.

Just inside inlet channel 64 are first and second inlet ball check valves 70 and 72. Directly above, these valves is a port 74 leading upward to storage chamber port 36, and being provided with a ball check valve 76.

Aligned with the upper piston housing bore 40 is lower bore or intake chamber 78 having near its upper end a shoulder 80. Intake chamber 78 communicates with the lower body inlet channel 64 by means of a horizontal connecting passage 82.

A threaded hole 84 in the lower face of lower body 16 receives rocker arm post 26. At the extreme right end of lower body 16 is a hole 86 through which suction tube 66 passes as it exits from oil well 12. Adjacent this hole is a threaded mounting hole 88 for the externally and internally threaded actuator rod sleeve 90 (FIG. 1). Externally threaded actuator rod stroke adjusting sleeve 92 is threaded through mounting sleeve 90. The actuator rod 22 is provided with lower and upper heads 94 and 95. These contact the corresponding ends of adjusting sleeve 92 and thereby act as positive stops for the respective ends of the rod stroke.

The return or downward stroke of plunger assembly 20 occurs under the influence of spring 96 which is compressed between the lower portion of lower body 16 and a spring retainer disk 98 which is mounted in slot 100 at the lower end of the plunger assembly (FIGS. 1 and 3).

Referring now to the details of the plunger assembly, best illustrated in FIG. 3, this assembly generally comprises an upper piston 102 having a T-shaped head 104 at its lower end which is received in a slot 106 at the upper end of lower piston 108 (FIG. 4). Upper piston 102 reciprocates within sleeve 112 provided with a pair of diametrically opposed ports 114. O-ring seals 116 are provided on the respective ends of sleeve 112.

Upper piston 102 is further provided with an annular groove 118 which communicates with a central bore or discharge chamber 120 by means of inlet 122. The lower end of discharge chamber 120 is provided with a tapered shoulder, and this passage is controlled by a ball check valve 124 under the influence of compression spring 126 retained by peening to form a retaining shoulder at the upper end of the bore. At the extreme upper end of sleeve 112 is a discharge ball check valve 128.

Operation The intake or downward stroke of the plunger assembly 20 is eflected by return spring 96. The upward or discharge stroke comes about from the downward stroke of actuator rod 22, which may be operated by a solenoid in response to a meter-driven switch. Such a system, more fully described in my prior Patent 3,213,215, provides a pump output which is directly proportional to the volume of water flowing in the main system.

As the plunger moves downwardly (see FIG. 7), lower piston 108 uncovers connecting passage 82 in lower body 16, thus permitting communication between lower body inlet channel 64 and intake chamber 78. The withdrawal of lower piston 108 from the upper end of intake chamber 78 creates a pressure drop within chamber 78, which unseats ball check valves 70 and 72 and seats check valve 76. Fluid is thus drawn upwardly into inlet channel 64 from the reservoir via suction tube 66. This fluid flows past check valves 70 and 72 and through passage 82 to fill the chamber defined by the space above lower piston 108 in chamber 78. Check valve 76 prevents any fluid from being drained out of storage chamber 30 into chamber 78.

Simultaneously and independently of this action, the downward stroke of upper piston 102 creates a low pressure in the upper portion of sleeve 112, thus seating discharge check valve 128 and unseating valve 124 against the compression of spring 126. As upper piston 102 nears the lower end of its stroke, annular groove 118 and inlet port 122 come into registry with ports 114 in sleeve 112. Thus, the reduced pressure in the space above upper piston 102 is applied to the chamber within sight glass 44, and fluid is drawn from the sight glass to fill the intake chamber above and within piston 102. The resulting low pressure created within sight glass 44 pulls fluid out of storage chamber 30 via ports 36 and 52 and channel 60 and port 58 (see FIGS. 6 and 7) to manifold 48 and into the upper end of the sight glass.

The intake or downward stroke of the plunger assembly fills the lower chamber in bore 78 from the outside chemical reservoir; and fills the upper chamber 120 from sight glass 44; and fills the sight glass from storage chamber 30.

When actuator rod 22 begins its downward stroke, the resulting upward stroke of the plunger assembly has a double effect, as shown in FIG. 8. First, the fluid filling intake chamber 78 above lower piston 108 is pumped across passage 82 and up into storage chamber 30 past the now lifted check valve 76. This flow also acts to seat check valves 70 and 72 to prevent fluid from being pumped back into the reservoir. The level of fluid in storage chamber 30 is controlled by overflow tube 32.

Simultaneously, in the upper section of the plunger assembly, the upward stroke of upper piston 102 seats check valve 124 and unseats discharge check valve 128, so that fluid may be discharged from the discharge chamber into the discharge line past discharge hole 42. Annular groove 118 of the upper piston passes above ports 114 in sleeve 112, thus lifting fluid and causing these ports to be blocked. This completes the two-stroke cycle of the pump.

Back siphonage is prevented in this unique pump in the following way. In the event that the head downstream from discharge port 42 is lost, the drop in pressure is applied to the interior of the pump, which lifts ball check valves 128 and 124 off of their seats. This drop in pressure then draws fluid from storage chamber 30 via port 36, passage 60, manifold 48, sight glass 44, passage 62 and ports 114. After the limited quantity of fluid in these passages has been siphoned off, the siphon will be broken by atmospheric vent 32 and 34, so that no further fluid can be drawn from inlet passage 64. This limited amount of fluid which can be back siphoned is insuflicient to cause any dangerous contamination of the municipal water supply.

It will be seen that this anti-siphonage arrangement is dependent upon atmospheric vent 34 in chamber 30. Overflow tube 32, which returns excess fluid to the reservoir assures that fluid will never fill to the level of vent 34. In the past, there was always a danger that the residue from evaporated chemical could clog such vents, thus eliminating this important anti-siphonage protection feature.

Several features contribute to the accurate control of pump output rate. The displacement of lower piston 108 is greater than that of upper piston 102, which results in storage chamber 30 being oversupplied with fluid relative to that which is drawn from chamber 30 into sight glass chamber 44. This assures that there will always be an adequate supply of fluid available to feed sight glass chamber 44. Secondly, since storage chamber 30, sight glass chamber 44 and discharge chamber 120 are all at substantially the same elevation, a minimum of vacuum is needed to transfer fluid between these various stages. Thus, the complete filling of discharge chamber 120 to the proper level is assured. Furthermore, this pump cannot become air locked, thus assuring reliable and continuous operation.

The in-line relationship of the upper and lower pistons contributes to smooth and reliable performance, since the tendency of the pistons to be laterally loaded is minimized. Thus, wear on the pistons and piston walls is minimized, and proper seals are maintained. When normal wear from extended operation does ultimately occur, the wear is taken on the pistons and on sleeve 112, all of which elements can be readily replaced. Heretofore, wear required scrapping the entire casting and pump, while here there is no problem of wear on the casting wall itself.

The reduction in wear and more perfect sealing permits the pump to operate against greatly increased pressure heads, and further assures that the chemical will not become contaminated with the lubricating oil nor Will the oil become contaminated by the chemical. In the past, leakage of chemical onto the outside of the mechanism due to worn, sloppy pistons and the subsequent evaporation has frequently resulted in fouling of the mechanism by the residue left from the chemical. The danger of contamination is also reduced by the fact that the chemical reservoir is located outside of the oil bath, communication being provided by the winding intake conduit 66.

The use of an oil bath to submerge the entire mechanism assures complete lubrication of all essential parts of the mechanism. This in turn, aids in reducing the noise created by the operation of the pump, an important advantage in a system which is connected to water pipes which are distributed throughtout an entire building.

Still another advantage results from the mounting arrangement for actuator rod 22. The in-line relationship of the two' pistons, permits both pistons to be adjusted simultaneously. This adjustment is eflfected by simply turning stroke adjusting sleeve 92 with a wrench, which functions to change the starting and stopping points of the actuator rod stroke as controlled by lower and upper heads 94 and 95 of the actuator rod.

I now claim:

1. A positive displacement pump for causing fluid to be drawn from a reservoir and discharged to an outlet at a predetermined rate comprising:

an inlet passage connected to the fluid reservoir and provided with one-way valve means for blocking reverse flow therethrough from the pump to the reservoir;

an intake chamber having a first piston slidably mounted therein, said intake chamber having a port establishing two-way communication to said inlet, said port being normally opened but blocked when said first piston is at the discharge end of its stroke;

actuating means for causing said first piston to reciprocate within said intake chamber;

a first storage chamber communicating with said inlet passage and provided with one-way valve means for preventing return flow from said first storage chamher to said inlet passage, said first storage chamber being further provided with a vent to atmosphere;

a second storage chamber having an inlet port connected to said first storage chamber and an outlet port, said second storage chamber being unvented; and

a discharge chamber axially aligned with and forming an extension of said intake chamber and having a second piston slidably mounted therein, said first and second pistons being connected together end to end for simultaneous intake and simultaneous discharge strokes, respectively, said discharge chamber having an inlet port connected to the outlet port of said second storage chamber, and further having a discharge port, said discharge chamber inlet port being normally closed but open when said second piston is at the intake end of its stroke, said discharge chamber discharge port having one-way valve means to prevent reverse flow through said port into said second discharge chamber.

2. The pump of claim 1 wherein said first and second storage chambers and said discharge chamber are all at substantially the same elevation, so that the reduced pressure created in said discharge chamber by the intake stroke of said second piston has a minimum head to lift against to cause fluid to flow from said first storage chamber to said second storage chamber to said discharge chamber.

3. The pump of claim 1 wherein the displacement of said first piston is greater than that of said second piston, and wherein said first storage chamber has an overflow tube to prevent the fluid level from exceeding a given level, whereby said first storage chamber is oversupplied with fluid relative to the intake demand of said discharge chamber.

References Cited UNITED STATES PATENTS 1,181,568 5/1916 Carter 10.3- 1,419,273 6/1922 La Bour 137-143 1,528,253 3/1925 Lanser 103-178 2,250,419 7/1941 Johnston et al 103-195 2,530,682 11/1950 Coldsnow 103-167 X 2,629,328 2/1953 Lacld 103-42 3,187,673 6/1965 Kramer 103-128 X WILLIAM L. FREEH, Primary Examiner US. Cl. X.R.

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