CA1112514A

CA1112514A - Fluid pump

Info

Publication number: CA1112514A
Application number: CA346,879A
Authority: CA
Inventors: Germain Belanger; Michel Kaine
Original assignee: POLYNERGIE Inc
Current assignee: POLYNERGIE Inc
Priority date: 1980-03-03
Filing date: 1980-03-03
Publication date: 1981-11-17
Also published as: GB2070697A; FR2477238A1

Abstract

ABSTRACT OF THE DISCLOSURE

The disclosure herein pertains to an improved and versatile fluid pump particularly suited for manual operation and fitting easily into a cylindrical well casing made of plastic material and in which a piston and a check valve, also made of plastic material, both have the same body structure so that the piston and the check valve may be used interchangeably by simply removing or adding minor components; these components include a plate valve adapted for sliding movement along a coupling rod integral with the body structure, sealing rings to provide adequate sealing and sliding contact with the internal wall of the well casing, and an adapter which is mounted to the lower part of the piston to form a check valve to secure it to the well casing.

Description

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FIELD OF THE INVENTION
i The present invention relates to improvements in fluid pumps of the type which includes a piston arranged ~ to be reciprocated in a cylinder by some means, usually - 5 manual, connected to the piston rod.
BACKGROUND OF THE INVENTION
It has been noted that existing pumping instal-- lations, especially in developing countries, are notori-ously unreliable and most imported hand pumps or small ~` 10 power pumps, originally designed for discontinuous use in single family households in developed countries, break-down after few months of continuous use in villages of developing countries. It has been observed that the original hardware is often inappropriate and hard to 15 maintain; spare parts and tools to maintain the pumps ~ are either missing or too costly and there is a lack of ;; local institutions or business willing or capable of , servicing these pumps. A further problem is cost; power ` pump installations are expensive and require sophisticated support services.
; OBJECTS AND STATEMENT OF THE INVENTION
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~'' It is an object of the present invention to provide a simple and reliable pumping system, especially ;~ designed for complete fabrication in developing countries;
`;~ 25 which can be produced at a cost which will enable such countries to expand rapidly the availability of safe drinking water supplies on a large scale. This object is achieved by providing a pump which can be installed, ' operated and serviced by rural residents in developing countries and others and which can overcome the problems often experienced with traditional hand pumps or open wells.
,::, The present invention concerns a pump that, ; contrary to the expensive conventional design with metal well casing, uses a plastic well casing or plastic lined .
; metal casing which acts as the pump cylinder itself. The ;

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2 -., - provision of a plastic pipe for a well casing results in smooth walls, thus vastly reducing friction between pipe and piston and allowing pumping with minimal physical efforts or other forms of energy supply. Such con-~ 5 struction lessens wear on piston rings which is a prime ; cause of pumps failure. Another advantage of the plastic pump is that there is no chemical reaction between the ~ pump and the water or ground, making it pollution-free.
`~ Further, in addition to being less expensive than other ;- lO types of pumps, most components of the present system can be readily available in developing countries where plastic pipes, such as pipes made of polyvinyl chloride, can be produced. Furthermore, a pump made of plastic as in the present invention is light and its components can be shipped easily and economically to remote locations.
- The present invention is also concerned with providing an improved design for a piston and a check valve for use with a plastic well or plastic lined metal casing. These components are made of plastic thus allowing for maximum hydraulic efficiency, minimum drag and wear through friction, while allowing for mass production at minimal cost.
` The present invention is therefore directed to a device which can be used interchangeably as a piston ' 25 and/or a check valve in a cylindrical well casing made ` of plastic material; the device comprises: a cylindrical body made of plastic material, including a top wall, a side wall and an opened base; aperture means in the top wall; peripheral groove means in the side wall; the - 30 body including upper and lower inner cavities defining a hollow lower chamber and a plurality of constricted upper chambers; a coupling rod, made of plastic material, integrally mounted to the body and extending axially with respect to the well casing; a plate valve axially and freely mounted about the coupling rod and adapted to cover the aperture means when resting on the top wall; sealing ' '' `' ` :

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means, made of plastic material, mounted to the body providing sealing and sliding contact with the internal wall of the well casing.
This device can be used as a piston or a check ~ 5 valve as both components are basically identical. When - the device is used as a piston, in one preferred embodi-ment of the invention, the groove means comprise a pair ; of vertically spaced recesses, in at least one of which is received a correspondingly shaped ring of plastic material therein. When the device is used as a check valve, the lower recess engagedly receives an adapter which will .. allow the check valve to be pushed downward into the ` well casing but which will prevent it from moving upwards ; when the pump is actuated and seals peripherally.
Other objects and statements of the invention will become apparent from the detailed description given hereinafter; however, it should be understood that this description while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art in reading this description.
BRIEF DESCRIPTION OF THE DRAWINGS
- Figure 1 is a schematic view of a well using a ` 25 pump made in accordance with the present invention;
- Figure 2 is a cross-sectional view of a piston used with the pump made in accordance with the present invention;
Figure 3 is a cross-sectional view taken along -~ 30 lines 3-3 of Fig. 2;
Figure 4 is an exploded view, partl~v cross-sectional, of a check valve used in a pump made in accordance with the present invention; and Figure 5 is an enlarged sectional view showing another embodiment of a check valve.

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DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to Fig. 1, there is shown a pumping ~;~ system using the present invention; it shows a brick pylon 10, mounted on a concrete base 12 and e~uipped with ; 5 a handle 14 and a spout 16. A cylindrical well casing 18 extends into a drilled borehole 20; the well may also be hand-dug. A pump rod 22 extends axially in the casing 18 and connects a piston 26 to the handle 14. A well screen 24 is provided at the bottom of the borehole while a check ; 10 valve 28 is provided at the bottom of casing 18.
A position of the casing 18 functions as a pump cylinder and at least that portion has a smooth internal surface to minimize wear. Most widely used thermoplastics for pipe production are rigid polyvinyl chloride, poly-15 ethylene and ABS. The advantage of a polyvinyl chloride pipe is that it can be easily joined in the field without ; special tooling or skill and also because the current state of commercial practice is such that a polyvinyl ; chloride pipe is generally freer of ovality.
Since the pipe is to be used for the supply of ` potable water, it should not contain material which are potentially injurious to health. In particular, lead stabilizer which are widely used in the polyvinyl chloride compounds are entirely unacceptable. The plastic material - 25 should be absent of toxic ingredients or coverings.
The pump rod 22 should preferably be buoyant enough to neutralize its own weight in water. This has the advantage that if the rod inadvertedly falls into the well, it can be retrieved easily because it floats.
' 30 A pump rod of polyvinyl chloride has many advantages over alternative wooden or metal rods. It is light and easy to transport; it is not subject to corrosion and does not swell or rot. It is not attacked by micro organisms ; and is sufficiently strong to activate the pump piston.
- 35 The well screen 24 is preferably a slotted poly-vinyl chloride member which is inserted in the bottom of -.

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the borehole 20 to provide influx of clean water to the displacement pump. This screen acts as a filter and may be provided in various sizes.
An impo~tant feature of the present invention, is that piston 26 and check valve 28, which are sub-merged in casing 18, are identically shaped. Referring to Figs. 2 and 4, respectively showing a piston and a check valve, each component includes basically a cylindri-cal body 30 including a top wall 32, a side wall 34 and an opened base 36. Each body 36 includes upper and lower cavities defining a hollow lower chamber 38 and a plurality of constricted upper chambers 39. In the embodiment shown, there are three chambers 39, each of which gradually reduces in cross-section area from the ~-~ 15 lower chamber 38 to a respective aperture 40 on the top wall of the body. The upper part of the body includes a central conical portion 42 so as to allow a coupling - rod 44 extending up from the top wall to form an integral ;~ part therewith, thus providing a unitary and homogeneous structure.
- Coaxially mounted to the rod 44 is a plate valve 46, preferably made of polyvinyl chloride, which ~ is adapted to reciprocate along the rod in the two p positions shown in Fig. 2. The plate valve has an outer diameter or shape to close apertures 40 on the top wall of the body when the plate valve rests on the top wall;
a pin 48 on the rod limits the upward movement of the plate valve 46. This pin may be fixed at an angle to the axis of the coupling rod allowing plate valve 46 to be tilted in the casing for increase flow area around ."!, the plate valve. The upper portion of the rod 44 has a tapered portion 50 to facilitate connection to the pump rod 22 and to compensate dimension tolerances. The taper section 50 allows the use of a variety of inner diameters of pump rods. The material of pump rod 22 should be compatible with that of rod 44 if both are glued together.

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In one variant of the present invention, the lower edge of the pump rod 22, once installed on the coupling rod 44, may also serve as a stop for limiting the upwards movement of the plate valve, in which case a pin 48 would not be required.
The outer side wall 34 of cylindrical body 30 - has two peripheral grooves 52,54 vertically spaced from one another and of varying width, upper groove 52 being larger than lower groove 54. In Fig. 2, where the body is to be used as a piston, a pair of rings 56,58 are , respectively mounted in grooves 52,54. These rings are split to provide easy installation to a groove and to adjust to a pipe diameter. These rings allow for any ovality in the structure of the internal wall of the cylindrical well casing by self-rotation in the optimum location by a play of forces acting thereon. Hence, the rings provide sealing and sliding contact with the internal wall of the casing. The rings are made of polyethylene. This material is preferred because of its relatively low coefficient of friction with poly-vinyl chloride. This reduces the pumping force required. In cases where only one ring should be used, ring 58 is omitted.
In Fig. 4, where the device is to be used as a check valve, groove 54 serves to engagedly connect an adapter 60 which itself has an internal groove 62 into which fits the lower extremity 64 of body 30. The adapter is made of polyethylene and its connection to body is by a snap-on engagement. The outer lower edge of adapter 60 has a peripheral sealing skirt 66 which engages and slides on ; the internal wall of the well casing when the check valve is positioned into the casing. However, the particular shape of the skirt prevents any upward movement of the check valve in the casing during pumping. Since the check valve is made of plastic and is inexpensive, should it be required to replace the check valve, the latter is simply pushed down into the borehole :

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- and another check valve is inserted as a replacement.
Ring 56 may or may not be used with the check valve.
In the design of the present invention, the piston and the check valve remain below the surface of water in the well; this means that the piston rings are - always wet and thus water lubricated. The particular shape of the inner chambers allows improved flow characteristics, - reducing turbulence and providing less restriction during reloading; also, there is minimum back pressure.
: 10 It has been said above that wear is negligeable between the piston rings and the pipe casing when a poly-vinyl chloride casing and polyethylene rings are used.
Even if wear should unexpectedly occur, it is a simple operation to shorten the piston rod, so that the piston rings travel on an unworn section of the well casing.
In the embodiment illustrated in Fig. 5, an O-ring 68 is provided between body 30 and adapter 60 to further sealing purposes.
' The pump of the present invention operates on a very simple principle: on the downstroke, water pressure forces the pipe valve in the piston to open and the identical plate valve in the check valve to close;
on the upstroke, the configuration is reversed in that the piston valve closes, water is drawn into the pipe casing through the opened check valve and is lifted a distance e~ual to the length of the stroke. With ., repeated strokes, water eventually reaches the collar of the well where it remains thereafter for easy hand or power pumping.
The piston and check valve of the present invention, can be removed for inspection and repair by one person onlyO In contrast conventional hand pumps - often require at least two persons for inspection and ` repair. Also, the piston and check valve being made of identical interchangeable components, stocking of spare parts is reduced to a minimum.

. - 8 -. Although the present invention is directed to a hand pump and is primarily designed for manual operation, . it can be easily understood that this pump can be used ~- with animal, wind, electric or diesel power. Hence, any ~; 5 reference to a hand pump should not be interpret~d as `. being limiting.
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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A device to be used as a piston and/or a check valve in a cylindrical well casing, made of plastic material, said device comprising:
- a cylindrical body, made of plastic material, having a top wall, a side wall and an opened base; aperture means in said top wall; peripheral groove means in said side wall; said body including upper and lower inner cavities defining a hollow lower chamber terminating at said base and a plurality of constricted upper chambers terminating at said top wall;
- a coupling rod, made of plastic material, integrally mounted to said body and extending axially with respect to said well casing;
- a plate valve axially and freely mounted about said coupling rod and adapted to cover said aperture means when resting on said top wall;
- sealing means, made of plastic material, mounted to said body providing sealing and sliding contact with the internal wall of said well casing.

2. A device as defined in Claim 1, further comprising stop means on said coupling rod for limiting upwards movement of said plate valve along said coupling rod.

3. A device as defined in Claim 1, wherein said constricted upper chambers gradually increase in cross-section from said aperture means on said top wall to said lower chamber.

4. A device as defined in Claim 1 and used as a piston, wherein said peripheral groove means include two vertically spaced recesses; said sealing means consisting of a pair of rings mounted in each said recess.

5. A device as defined in Claim 1 and used as a check valve, wherein said peripheral groove means include two vertically spaced recesses; said sealing means consisting of adapter means mounted to said body adjacent said base, said adapter means having means engaging the lowermost of said two recesses.

6. A device as defined in Claim 5, wherein said adapter means is made of polyethylene.

7. A device as defined in Claim 5, wherein said adapter means include skirt means on the outer side wall thereof to engage the inner wall of said well casing to sealingly secure said check valve in said casing.

8. A device as defined in Claim 1, 5 or 7, wherein said plate valve is made of plastic.

9. A device as defined in Claim 1, 5 or 7, wherein said body is made of polyvinyl chloride.

10. A device as defined in Claim 5, including a ring in the uppermost of said two recesses.

11. A device as defined in Claim 4 or 10, wherein said rings are made of polyethylene.

12. A hand pump comprising: a cylindrical well casing made of plastic material, having a smooth inner wall, said well casing defining a piston-cylinder; a pair of identically-shaped cylindrical bodies, made of plastic material, received in said casing, one of said bodies being fixedly mounted in said casing, the other of said bodies being slidable therein above said one body; each said body including: a top wall having aperture means thereon, a side wall having upper and lower groove means therein, and an opened base; each said body including upper and lower inner cavities defining a hollow lower chamber terminating at said base and a plurality of constricted upper chambers, in fluid communication with said lower chamber, terminating at said top wall; a coupling rod, made of plastic material, integrally mounted to each top wall of said body and extending axially with respect to said well casing; a plate valve axially and freely mounted about each said coupling rod and adapted to cover said aperture means of each said body when resting on said top wall; stop means on each said coupling rod for limiting upward movement of said plate valve along said coupling rod; ring means, made of plastic material, mounted in said groove means of said other body to provide sliding and sealing contact with said inner wall of said casing whereby said other body acts as a piston in said casing and said casing acts as a piston-cylinder; and adapter means mounted to said one body and having means engaging the lower groove means of said one body to sealingly secure said one body against said inner wall of said well casing whereby said one body acts as a check valve in said casing.

13. A hand pump as defined in Claim 12, wherein the lower portion of said adapter means defines an outer skirt contacting said inner wall of said casing, said skirt allowing said one body to slide downward into said well casing but preventing upward movement thereof during pumping.

14. A hand pump as defined in Claim 12, further comprising a pump rod, made of buoyant plastic material, attached, at one end thereof, to said coupling rod of said other body.