Patent Description:
The present disclosure relates to pneumatically actuated fluid pumps, and more particularly to a fluid pump incorporating a swirl inducing element for introducing a counter rotational swirling action during fill and discharge cycles of the pump to help clean interior surfaces and interior components of the pump.

Pneumatic fluid pumps are used in a wide variety of applications. One particularly important application is at landfills to pump water and water mixed with leachate from landfill wells. This application presents particularly challenging issues with keeping the internal components of the pump clean. The contaminated fluids that need to be pumped can quickly cause fouling of the pump, and particularly the movable internal components of the pump such as an internal float, movable linkage elements and other components. Cleaning of such pneumatically operated pumps can be time consuming and costly. Prior art in this technical field is disclosed in documents <CIT> and <CIT>.

Accordingly, there is a strong interest in any improvements and features which help to prolong the interval between cleanings of a pneumatically driven pump and which contribute to more reliable pump operation.

The present invention relates to a fluid pump according to claim <NUM>.

In another aspect the present disclosure relates to a fluid pump. The fluid pump may comprise a pump outer casing and a top cap securable to an upper end of the pump outer casing and having an air intake port and a fluid discharge port. A fluid discharge tube may be included which extends to a point adjacent a lower end of the pump outer casing. A one-way check valve is disposed in the pump outer casing adjacent the lower end of the pump, and forms a one-way path to admit fluid into the pump outer casing during a fill cycle of operation of the pump. An auger subassembly is included which is disposed inside the pump outer casing. The auger subassembly causes a first swirling, rotational fluid flow during a fluid fill cycle of operation of the pump, where fluid is being admitted into the pump outer casing through the one-way check valve. The auger subassembly also causes a second swirling, rotational fluid flow during a fluid eject cycle of operation of the pump, in response to the jet of pressurized air released into the pump outer casing. This causes fluid having collected within the pump outer casing to be forced by the jet of pressurized air into and up through the discharge tube, and out from the pump outer casing. The auger subassembly forms a unitary subassembly that may be slid over the fluid discharge tube or integrated with the pump's casing and secured thereto during assembly of the pump.

The present invention further relates to a method according to claim <NUM> for pumping fluid using a pneumatically operated fluid pump.

Referring to <FIG> and <FIG> there is shown a pneumatic pump <NUM> (hereinafter simply "pump" <NUM>) in accordance with the present disclosure. The pump <NUM> is especially well suited for pumping contaminated liquids that are likely to cause contaminants and sludge buildup in the pump, such as in landfill well applications, although it will be appreciated that the pump <NUM> may be used in any application where it is important to maintain the inner workings of the pump clean and free of a buildup of contaminants.

As shown in <FIG> and <FIG>, the pump <NUM> includes a pump casing <NUM>, a pump cap <NUM> having an air inlet <NUM> for receiving compressed air from a compressed air source, and a coupling <NUM>, which forms a one-way check valve, for connecting to a fluid carrying discharge conduit <NUM>. A lower end of the pump casing <NUM> includes a screen <NUM> secured thereto, and a one-way check valve assembly <NUM>. The one-way check valve assembly <NUM> is made up of a three-legged spider assembly <NUM> having an upper wall portion 24a and sleeves 24b, a poppet element <NUM> captured within the three-legged spider assembly, a valve seat member 25a' having a valve seat 25a, an O-ring 25b which fits in a circumferential groove 25c on the valve seat perimeter, and a three legged frame 25d over which the screen <NUM> fits. A plurality of threaded fasteners 25e may be used to secure the legs of the three-legged spider assembly <NUM> to the valve seat member 25a' via holes 25a1 in the valve seat member 25a'. The one-way check valve assembly <NUM> allows fluid flow in one direction only (i.e., into the pump casing <NUM> from outside the pump <NUM>).

With further reference to <FIG> and <FIG>, a discharge tube <NUM> is in fluid communication with the coupling <NUM> to allow the ejection of fluid up through the two oppositely arranged openings 28b (only one being visible in the figure) in the discharge tube <NUM> and into the fluid carrying discharge conduit <NUM>. A float <NUM> is disposed around the discharge tube <NUM>. A spring cup <NUM> is secured at an end of a control rod <NUM> via a pin 32a, which extends through opening 32b, and enables a spring 31a to be held on to the end of the control rod <NUM>. The control rod <NUM> is associated with a valve (not shown) that helps to control the admission of air into the pump casing <NUM> through the air inlet <NUM>.

The float moves up and down along the outer surface of the discharge tube in response to changing fluid levels in the pump casing <NUM>. The float <NUM> actuates a conventional air admission control valve assembly (not visible in the Figure) located near an upper end of the pump casing <NUM> which opens an air admission control valve when the float reaches a predetermined upper limit of travel, indicating the pump is full with liquid and that an ejection cycle needs to be commenced. The compressed air is directed as a jet through the air inlet <NUM> towards a lower end of the pump casing <NUM>. The air forces liquid which has collected in the pump casing <NUM> into the discharge tube <NUM> through the ports 28a. As the float <NUM> descends to a predetermined lower limit as fluid is pumped up through the discharge tube <NUM>, the air admission valve is closed, a vent valve (not shown) is opened to vent the pump casing <NUM>, and the fill cycle repeats itself. The components <NUM>-<NUM> are well known components often used with pneumatic, auto-cycling pumps, and as such no further description will be provided. The assignee of the present disclosure, QED, Inc. , is a leader in the manufacture and sale of pneumatically actuated auto-cycling pumps such as described above.

The pump <NUM> of the present disclosure differs from conventional pneumatic, auto-cycling pumps through the incorporation of a swirling flow inducing auger element <NUM>, best seen in <FIG>. The auger element <NUM> forms a helical shaped component having an outer diameter just slightly smaller than an inner diameter of the pump casing <NUM> so that it can be easily slid into the pump casing during initial assembly of the pump <NUM>. The auger element <NUM> may be made from any suitable material, for example high strength plastic such as PPS, or a metal material, for example <NUM> stainless steel or aluminum. The auger geometry could also be integrated with pump casing <NUM>.

With specific reference to <FIG> and <FIG>, the auger element <NUM> includes an upper end <NUM>, a mid-portion <NUM> and a lower end <NUM>. At the upper end <NUM> the auger element <NUM> forms a central opening <NUM> having a diameter just slightly larger than the outer diameter of the discharge tube <NUM>, such that the discharge tube can extend at least partially through the auger element. The upper end <NUM> has a upper radial wall section 38a having a radial length that substantially extends to fill the space between an outer surface 28a of the discharge tube <NUM> and an inner surface 12a of the pump casing <NUM>. A mid radial wall section 40a of the mid portion <NUM> is substantially similar, or the same, as that of the upper radial wall section 38a, but includes an angular edge 40b. The angular edge 40b provides clearance for the auger element <NUM> to extend around the spider assembly <NUM> when assembled into the pump casing <NUM>. The mid radial wall section 40a narrows down considerably to a lower radial wall section <NUM> that extends in a helical path to a distal end <NUM> of the auger element <NUM>. The distal end <NUM> in this example includes a hole <NUM> to allow passage of one of the legs of the spider assembly <NUM> to pass through when the auger element <NUM> is installed in the pump casing <NUM>. The upper radial wall section 38a, the mid radial wall section 40a and the lower radial wall section <NUM> form a continuous radial helical wall section. The wall sections 38a, 40a and <NUM> cooperatively from an open at a radial center of the auger element <NUM> such that the discharge tube <NUM> is centered within the auger element.

The overall length of the auger element <NUM> may vary to meet the needs of a specific pump application. However, it is anticipated that in most embodiments the auger element <NUM> will have a length sufficient to extend from the upper wall section 24a of the spider assembly <NUM> up and over at least a portion of the discharge tube <NUM>. The amount of float <NUM> travel will have a large bearing on the permissible overall length of the auger element <NUM>, as the auger element should not interfere with descending elevational movement of the float.

It will be appreciated that in some applications it may be desirable to form the auger element <NUM> in two or more distinct sections to fit together adjacent one another, and in some instances, this may even further simplify assembly of the auger element <NUM> into the pump casing <NUM>. This may be particularly so if the auger element <NUM> is being retrofit into an existing pump. Both a single component and multi-component embodiment of the auger element <NUM> is contemplated by the present disclosure. Furthermore, the auger element <NUM> may be formed from one, two or more helical wires 36a' with an attached planar-like section 36b', as shown for example in <FIG> by the auger element <NUM>'. In this example the auger element 36a' may also include a separately formed plate-like element 36c' at a lower end with a suitable sized hole 36d to enable easy attachment to one of the three legs of the three legged spider assembly <NUM>. Still further, the hole 36d could instead by formed like a clip that enables it to be slid over one of the three legs of the three legged spider assembly <NUM>. Still further, the auger element <NUM> may be formed (e.g., molded) as a single piece component from a suitable strong plastic, or formed as a single piece component from metal (e.g., stainless steel). As such, the auger element <NUM> or <NUM>' is not limited to any one particular form of construction or any single material.

Once installed in the pump casing <NUM>, the distal end <NUM> of the auger element <NUM> may rest on, or be secured in any suitable manner, to the flat upper wall section 24a of the spider assembly <NUM>, while the upper end of the auger element <NUM> rests freely, or alternatively engages a threaded feature on the upper wall portion 24a of the three legged spider assembly <NUM>, or a feature molded on, or otherwise secured to, the exterior surface 28a of the discharge tube <NUM>. Such a feature that enables attachment to the upper wall portion 24a may be formed on the upper wall portion 24a itself, or the attachment feature may be formed on the upper radial wall section 38a near the upper end of the auger element <NUM>. Still further, the upper radial wall section 38a could be threaded so that a separate fastener can be used to secure it to the upper wall portion 24a or possibly to a mid-point of the discharge tube <NUM>. In all of the above configurations, the upper end of the auger element <NUM> will be captured and held stationary within the pump casing <NUM>. Thus, the auger element <NUM> can be assembled into, and disassembled from, the pump <NUM> without necessitating any significant re-design of the major pump components (e.g., float <NUM>, spider assembly <NUM>, discharge tube <NUM>, etc.).

Referring to <FIG>, the operation of the pump <NUM> and particularly the operation of the auger element <NUM> will be described. The auger element <NUM> provides a dual rotational fluid flow feature in which fluid flowing past the poppet element <NUM> and entering the pump casing <NUM> is caused to flow in a first swirling, rotational direction, indicated by arrows <NUM>, as the liquid fills the lower end of the pump casing <NUM>. This helps to clean the poppet element <NUM>, the valve seat 25a, and the structure of the spider assembly <NUM>, as well as the inside wall 12a of the pump casing <NUM> to the highest point which the fluid (e.g., water) reaches inside the pump casing 12a. The float <NUM> is then cleaned all the way up to the top of the waterline of buoyancy on the float.

When the liquid entering the pump casing <NUM> fills to a predetermined upper level, the air control valve (not shown) admits pressurized air into the pump housing <NUM> through air inlet <NUM> to begin a fluid eject cycle. This induces a strong swirling fluid flow inside the pump casing <NUM> in a second rotational direction, denoted by arrows <NUM> in <FIG>. The helical-like swirling flow <NUM> is in the opposite rotational direction as the swirling flow <NUM> during the fill cycle. The swirling flow <NUM> is forced into opposing discharge ports 28a (only one being visible in <FIG>) at a lower end of the discharge tube <NUM>, and then up through the discharge tube <NUM> into the fluid discharge conduit <NUM>. The strong swirling flow <NUM> provides a significant cleaning effect to help break loose contaminant particles that may be sticking to the outer surface of the float <NUM>, the outer surface 28a of the discharge tube <NUM>, as well as on the inside surface 12a of the pump casing <NUM>, on portions of the spider assembly <NUM> and the poppet element <NUM>, and even on the auger element <NUM> itself, during the fluid eject cycle.

A particular advantage provided by auger element <NUM> is the abrupt transition in flow direction that occurs within the pump casing <NUM> when switching from the fluid fill cycle to the fluid eject cycle. This abrupt transition in flow creates a strong turbulent flow action inside the pump casing <NUM>. The flow direction changes from the swirling flow <NUM> to swirling flow <NUM> within milliseconds, which creates an especially strong, momentary, turbulent "burst" of fluid as the fluid flow abruptly changes direction by <NUM> degrees. This abrupt "burst" of turbulent flow provides an especially strong cleaning action on the exterior surface of the float <NUM>, as well as on the inside wall 12a of the pump casing <NUM>, on the auger element <NUM> itself, and even on at least a portion of the float <NUM>, without detracting in any way from carrying out the fluid eject cycle of operation of the pump <NUM> and discharge tube <NUM>.

Referring to <FIG>, an auger element <NUM>" in accordance with another embodiment of the present disclosure is presented. The auger element <NUM>" in this example includes offset step or ramp portions 36a" which are interconnected by generally flat portions 36b" to form a continuous, circumferential, helical, flow swirl inducing element. One of the ramp portions 36b" may include a hole 36c" to enable a threaded bolt to be used to secure one end of the auger element <NUM>" fixedly within the pump casing <NUM>.

The auger element <NUM>" provides a significant advantage in that with the opposing arrangement of the offset flat portions 36a", the auger element <NUM>" can be injection molded using a conventional two part injection molding tool. Another advantage of the auger element <NUM>" is that the ramp portions 36a" are substantially shallower in angle than the auger element <NUM> or the auger element <NUM>'. This enables a great number of turns to be implemented with the auger element <NUM>" in any give longitudinal space. With the auger element <NUM>", the angle of each ramp portion 36a" relative to a horizontal line A as shown in <FIG>, is about <NUM> degrees - <NUM> degrees, and more preferably about <NUM> degrees - <NUM> degrees. Thus, even in pump applications where the auger element <NUM>" has limited longitudinal space to impart a strong swirling motion, the additional turns and reduced spacing between the ramp portions 36a" significantly helps to impart a strong swirling motion to the fluid during both the discharge and intake cycles.

<FIG> shows the auger element <NUM>" but where the upper end is truncated to remove the uppermost flat portion 36b. <FIG> also shows a threaded fastener 36d" which may be used to secure the auger element <NUM>" to the upper surface 24a of the three-legged spider assembly <NUM> when the three-legged spider assembly is fully assembled to the valve seat member 25a' of the one-way valve assembly <NUM>. <FIG> shows the auger element <NUM>" fully assembled into the pump <NUM> by attachment to the upper wall portion 24a of the three-legged spider assembly <NUM>. Alternatively, the auger element <NUM>" could just as readily be attached to the valve seat member 25a', provided sufficient clearance exists between the sleeves 24b of the three-legged spider assembly <NUM> and the interior wall of the pump casing <NUM>. Attachment to valve seat member 25a' enables an overall longer length for the auger element <NUM>" to be implemented, which may even further improve the strength of the swirling flow that the auger element induces during one or both of the fluid intake and fluid eject cycles.

The auger element <NUM>" may be made from a suitable high strength plastic. Alternatively, the auger element <NUM>" may be made from stainless steel or any other suitably durable material. The auger element <NUM>" may be constructed in to pieces which are adapted to be positioned adjacent to one another in an interlocking manner, or it may be manufactured as a single piece component as shown in <FIG>. Both constructions are contemplated by the present disclosure.

<FIG> shows the auger element <NUM>" in another embodiment including a spacer element 36e". The spacer element 36e" sets an offset distance from the surface (either upper surface 34a or the valve seat member 25a) to which the auger element <NUM>" is attached, and may further help to prevent breakage of the auger element during installation.

Referring to <FIG> and <FIG>, there is shown another embodiment of the auger element which forms a complete auger subassembly <NUM> for use with the pump <NUM> of <FIG>. The auger subassembly <NUM> may be installed concentrically over an existing fluid discharge tube, such as <NUM> shown in <FIG>, as will be explained in greater detail in the following paragraphs. <FIG> shows the major components of the auger subassembly <NUM> separated from one another. The auger subassembly <NUM> may be constructed as a permanently attached portion of the discharge tube <NUM>. Alternatively, the auger subassembly <NUM> may be formed as a fully separate subassembly, as shown in <FIG> and <FIG>, and secured by suitable threaded fasteners, as will be explained in greater detail in the following paragraphs. The auger could also be integrated in to the pump casing <NUM>.

The auger subassembly <NUM> in this embodiment includes a barrel portion <NUM> around which are secured a pair of auger sections 104a and 104b. The auger sections 104a and 104b, often referred to as "flights" by those skilled in the art, form helical-like elements that may be permanently secured to an outer surface 102a of the barrel portion <NUM>. In one implementation the auger sections 104a and 104b may be secured by spot welds <NUM>, such that, in this embodiment, the entire auger subassembly <NUM> forms a single piece subassembly once fully constructed. Optionally, the auger sections 104a and 104b may be press fit onto the barrel portion <NUM>. Other attachment implementations may also be used, as will be explained in the following paragraphs. Also, while two auger sections 104a and 104b are shown, it will be appreciated that the present disclosure may make use of one, three or greater number of auger sections. The present disclosure is therefore not limited to use with any particular number of auger sections.

In effect, the two auger sections 104a and 104b form a continuous helical-like auger element once secured to the barrel portion <NUM>. And while spot welds are one suitable method for joining the auger sections 104a and 104b to the barrel portion <NUM>, suitable adhesives may also be used for permanently securing the auger sections 104a and 104b. Still further, press-pins, interference fit geometry, or possibly even rivets could be used to secure the auger sections 104a and 104b to the barrel portion <NUM>. If welding is used, V-groove or butt welds may be needed to secure the abutting ends of the auger sections 104a and 104b, possibly along with a small degree of surface grinding to leave a smooth continuous transition between the two auger sections. Honing of the interior of the barrel portion <NUM> may also be helpful after the welding has been performed to ensure diametric/cylindricity tolerances.

An internal diameter of the barrel section <NUM> is selected to be just slightly larger than the exterior diameter of the discharge tube <NUM> such that the barrel portion can be slid over the discharge tube during assembly of the pump <NUM>, and further such that the barrel portion has minimal play once it is positioned over a portion of the discharge tube <NUM>. The barrel portion <NUM> is preferably made from stainless steel or another suitable corrosion-resistant material, or possibly even high strength plastic. It is expected that stainless steel will be an especially preferred material in view of the harsh environment in which the pump <NUM> will be expected to operate in.

Referring further to <FIG> and <FIG>, the barrel portion <NUM> can be seen in isolation. The barrel portion <NUM> includes a pair of generally U-shaped notch sections <NUM> arranged <NUM> degrees from one another, which keeps the openings 28b in the discharge tube <NUM> clear to allow fluid to be admitted into the discharge tube <NUM> during a fluid ejection cycle. Notches <NUM> and <NUM> at the upper and lower ends, respectively, of the barrel portion <NUM> help to facilitate alignment and attachment of the auger sections 104a and 104b. Threaded openings <NUM> and <NUM> may be used to receive threaded set screws (not shown), which enable the barrel section <NUM> to be releasably attached to the discharge tube <NUM> to permit easy removal for cleaning purposes. Elongated slot <NUM> helps to secure both a lower end of the upper auger section 104a and an upper end of the lower auger section 104b, as will be discussed momentarily.

Referring further to <FIG>, each of the auger sections 104a and 104b include a first projecting tab <NUM> at a first inside edge of an upper end thereof, and a second projecting tab <NUM> at a second inside edge of a lower end thereof. The auger sections 104a and 104b may be made from stainless steel, high strength plastic, or any other suitably strong material that is preferably highly resistant to corrosive fluids and sludge. The sheet metal auger sections 104a and 104b permit a small degree of flexing thereof during their assembly onto the barrel portion <NUM>. The inside edge <NUM> of each of the auger sections 104a and 104b forms an opening of a diameter which is just slightly larger than the outer diameter of the barrel portion <NUM>. In this example the auger sections 104a and 104b are identical in construction (i.e., identical in dimensions, thickness, shape and material), although they need not necessarily be identical in construction.

As best seen in <FIG>, the auger sections 104a and 104b each have a length section <NUM> which is selected so that the auger elements 104a and 104b will substantially fill the space (i.e., leaving a minimal clearance on the order of about a few thousands of <NUM>,<NUM> [an inch]) between the outermost edge of the auger sections <NUM> inside the outer casing <NUM> of the pump <NUM> once the auger assembly <NUM> is fully assembled and installed in the pump. In other words, the outer diameter of each of the auger sections 104a and 104b is just slightly less than an inner diameter of the outer casing <NUM>, which enables the auger sections 104a and 104b.

The auger section 104a is shown in <FIG> after being cut at line <NUM>. The cut at line <NUM> helps to create the projecting tabs <NUM> and <NUM>. <FIG> shows the auger section 104a from a plan view after additional material removal at the cut line. The auger section 104a is shown in <FIG> after being bent into its finished shape.

With further brief reference to <FIG>, to assemble the auger subassembly <NUM> the upper auger section 104a may be first assembled onto the barrel portion <NUM>. This involves flexing the auger section 104a to fit it over the upper end of the barrel portion <NUM> such that the projecting tabs <NUM> and <NUM> engage within the notch <NUM> and the slot <NUM>, respectively. Then the lower auger section 104b may be slipped over the lower end of the barrel portion <NUM> such that its first projecting tab <NUM> also fits into the slot <NUM>, and the second projecting tab <NUM> fits in the notch <NUM>. At this point a plurality of the spot welds <NUM> (shown in <FIG>) may be applied to permanently secure the auger sections 104a and 104b to the barrel portion <NUM>. In this embodiment, then, the entire auger subassembly <NUM> may then be slipped over the discharge tube <NUM> and threaded set screws (not shown) used to secure the auger assembly at a desired axial location on the discharge tube which keeps the openings 28b clear for fluid flow into the discharge tube. As noted above, other attachment means such as a press fit pin, rivets, or mating geometry may be used to form the attachment. The auger subassembly <NUM> operates in the same manner as described above for the auger element <NUM>.

Referring to <FIG>, another implementation for securing the auger subassembly <NUM>' to the fluid discharge tube is shown. This implementation provides the important advantage of quickly helping angulary align the barrel portion <NUM> with the openings 28b on the fluid discharge tube <NUM>. To accomplish this an upper U-shaped notch 108a may be formed in the barrel portion <NUM>. A locating tab <NUM> having a diameter just slightly smaller than the width of the upper U-shaped notch 108a may be fixedly secured to the fluid discharge tube <NUM> such as by welding, adhesives, a threaded screw, etc. The locating tab may be plastic, metal or made from any other suitable material, and preferably has a slight arc with a radius of curvature which generally conforms to the outer diameter of the barrel portion <NUM>. In this manner, once attached to the fluid discharge tube <NUM>, the locating tab <NUM> will sit flush over its full inside surface with the outer surface of the fluid discharge tube. The locating tab <NUM> is circumferentially positioned such that when the barrel portion <NUM> is slid onto the distal end of the discharge tube <NUM>, the upper U-shaped notch 108a will engage with the locating tab <NUM> and position the lower notch <NUM> in alignment with the openings <NUM>. To retain the auger subassembly <NUM>' on the discharge tube a snap ring <NUM> may be used which engages with a channel (not visible) in the figure at the distal end of the discharge tube <NUM>. However, any other suitable attachment method may be provided, such as a set screw, or a press fit pin or other type of interference geometry coupling. Preferably, the method of attachment used will permit quick and easy removal of the auger subassembly <NUM>' for cleaning or repair purposes. The use of the locating tab <NUM> in connection with the upper U-shaped notch 108a significantly enhances the speed and accuracy of assembly of the auger subassembly <NUM>', and essentially ensures that the auger subassembly cannot be installed in a manner that would block the openings 28b in the fluid discharge tube <NUM>.

Referring to <FIG>, various additional attachment methods are disclosed for securing the auger assembly <NUM> or <NUM>' to the fluid discharge tube <NUM>. Merely for convenience, the auger assembly <NUM> will be referenced in the following discussion of <FIG>.

<FIG> shows a threaded bolt <NUM> which may be inserted through aligned, opposing holes <NUM> in the barrel section <NUM>, and also through aligned holes <NUM> in the barrel portion <NUM>, and secured using a threaded nut <NUM>. Optionally an elongated press fit pin may be used. The holes <NUM> and <NUM> are preferably arranged on such that once the threaded bolt (or elongated pin) is inserted, the barrel portion <NUM> will be correctly positioned on the discharge tube with the holes 28b clear.

<FIG> shows another attachment method that uses at least one rivet or short threaded bolt <NUM> which extend through the openings <NUM> and <NUM>.

<FIG> shows still another attachment method where a threaded bolt <NUM> is positioned to extend through an opening in a flange <NUM>, where the flange <NUM> is fixedly attached to the barrel portion <NUM> and extends out laterally from the barrel portion <NUM>. The threaded bolt <NUM> in this example extends through a hole in the spider <NUM>, through a tubular spacer <NUM>, and into a threaded hole <NUM> in the frame member <NUM> associated with the spider. The tubular spacer <NUM> has a length selected so properly set the axial position of the auger subassembly <NUM> on the discharge tube <NUM>. In this example the flange <NUM> is located on the barrel portion <NUM> such that the barrel portion, once attached to the spider <NUM>, will be properly circumferentially aligned with the holes 28b in the fluid discharge tube <NUM>. So the auger subassembly <NUM> is both axially and circumferentially aligned on the fluid discharge tube <NUM> using the flange <NUM> and threaded bolt <NUM>.

It will be appreciated that with the attachment implementations shown in <FIG>, the use of the snap ring <NUM>, while shown in the figures, may not be needed to secure the auger subassembly <NUM> to the fluid discharge tube <NUM>.

The auger subassembly <NUM> provides several important advantages, one of which is its ability to be quickly and easily removed from the discharge tube <NUM> for cleaning. No special tools beyond possibly a screw driver are needed for this task. If a portion of the auger subassembly <NUM> is discovered to be damaged (i.e., bent), the entire auger assembly <NUM> can be easily replaced without any modifications being required on the discharge tube <NUM> or any other portion of the pump <NUM>. The construction of the auger subassembly <NUM> as a complete subassembly also potentially enables it to be retrofitted to existing pump structures with little or no modifications to the pump structure.

The use of two separate auger sections 104a and 104b further significantly eases fabrication of the auger sections from separate sections of metal, as well as easing assembly of the auger sections onto the barrel portion <NUM>. The auger subassembly <NUM> also forms a relatively inexpensive portion of the overall pump <NUM>, thus helping to maintain a highly economical pump construction, while still providing the benefits of creating a strong swirling fluid flow during every pump cycle of the pump, which helps significantly to maintain the interior of the pump clean and free from sludge and debris build up.

The self-cleaning operation provided by the auger element <NUM>, as well as the auger subassembly <NUM>, does not add significant complexity, cost or weight to the pump <NUM>, nor does it significantly complicate assembly or disassembly of the pump <NUM>. The auger element <NUM> or the auger subassembly <NUM> may also be retrofitted into existing pumps, with the only possible modification required possibly being the addition of structure at the spider assembly <NUM> or along the discharge tube <NUM> to hold the auger element or the auger subassembly in place once assembly is complete. In the unlikely event that the auger element <NUM> or the auger subassembly <NUM> should break, removal and replacement is easily accomplished once the discharge tube <NUM> is removed from the pump casing <NUM>.

Claim 1:
A fluid pump (<NUM>) comprising:
a pump casing (<NUM>);
a top cap securable to an upper end of the pump casing and having an air intake port and a fluid discharge port;
a fluid discharge tube (<NUM>) extending to adjacent a lower end of the pump casing;
a first one-way check valve adjacent the lower end of the pump, forming a one-way path to admit fluid into the pump casing during a fill cycle of operation of the pump and a second one-way check valve at the pump's discharge port to release fluid during a discharge cycle; characterised by
an auger element (<NUM>) disposed inside the pump casing (<NUM>) and extending at least partially around the discharge tube (<NUM>) such that the discharge tube (<NUM>) extends at least partially through the auger element (<NUM>), and the auger element (<NUM>) disposed between an outer surface of the fluid discharge tube (<NUM>) and an inside surface of the pump casing (<NUM>), the auger element (<NUM>) configured to cause a swirling, rotational fluid flow in a first direction about the fluid discharge tube (<NUM>) during the discharge cycle, the discharge cycle occurring in response to a jet of compressed air released into the pump casing (<NUM>) in which fluid having collected within the pump casing is forced by the jet of compressed air into and up through the discharge tube (<NUM>) and out from the pump casing (<NUM>);
wherein the swirling, rotational fluid flow helps to clean the inside surface of the pump casing (<NUM>) and the outer surface of the fluid discharge tube (<NUM>) by breaking loose contaminant particles on the inside surface and the outer surface to remove the contaminant particles.