Diaphragm pumps with air savings devices

In at least one illustrative embodiment, a diaphragm pump may include a sleeve formed to include (i) a bore extending along a longitudinal axis and (ii) a sleeve port that opens to the bore, and a spool supported in the bore of the sleeve and formed to include a spool port, the spool being configured to move with a diaphragm during at least a portion of a stroke of the diaphragm such that the spool slides relative to the sleeve and, when the diaphragm reaches a turndown position that is between first and second end-of-stroke positions, the spool port aligns with the sleeve port to cause a pilot signal to be supplied to a cut-off valve. At least one of the sleeve and the spool may be rotatable about the longitudinal axis to adjust a location of the turndown position relative to the first and second end-of-stroke positions.

TECHNICAL FIELD

The present disclosure relates, generally, to diaphragm pumps and, more particularly, to diaphragm pumps with air savings devices.

BACKGROUND

Double diaphragm pumps alternately pressurize and exhaust two opposing motive fluid chambers to deliver pumped media during each stroke of the pump. Pressurizing the motive fluid chambers often results in operating efficiency losses as some of the motive fluid communicated to the chambers during each stroke does not contribute to the pumping action. In an attempt to mitigate this shortcoming, some prior pumps have interrupted the supply of motive fluid using devices having electrical components. Such pumps, however, may have limited utility in industrial applications where the use of electrical components necessitates safety measures that are not typically required for purely mechanical devices.

SUMMARY

According to one aspect, a diaphragm pump may comprise a first diaphragm that separates a first cavity into a first motive fluid chamber and a first pumped media chamber, where the first diaphragm is configured to stroke from a first end-of-stroke position to a second end-of-stroke position in response to compressed fluid being communicated from a compressed fluid inlet to the first motive fluid chamber. The diaphragm pump may further comprise a cut-off valve configured to communicate compressed fluid from the compressed fluid inlet to the first motive fluid chamber in response to receiving a first pilot signal and resist communication of compressed fluid from the compressed fluid inlet to the first motive fluid chamber in response to receiving a second pilot signal. The diaphragm pump may further comprise a sleeve formed to include (i) a bore extending along a longitudinal axis and (ii) a first sleeve port that opens to the bore, where the first sleeve port is fluidly coupled to the cut-off valve via a pilot line. The diaphragm pump may further comprise a spool supported in the bore of the sleeve and formed to include a first spool port, where the spool is configured to move with the first diaphragm during at least a portion of the stroke of the first diaphragm such that the spool slides relative to the sleeve and, when the first diaphragm reaches a turndown position that is between the first and second end-of-stroke positions, the first spool port aligns with the first sleeve port to cause the second pilot signal to be supplied to the cut-off valve via the pilot line. At least one of the sleeve and the spool may be rotatable about the longitudinal axis to adjust a location of the turndown position relative to the first and second end-of-stroke positions.

In some embodiments, the first sleeve port may include a sidewall disposed at an acute angle to a circumference of the sleeve. The diaphragm pump may further comprise a housing defining the first cavity and supporting the sleeve. The housing may be formed to include a first keyed feature, and the spool may be formed to include a second keyed feature, where the first keyed feature is configured to mate with the second keyed feature to resist rotation of the spool about the longitudinal axis.

In some embodiments, the sleeve may be further formed to include (i) a second sleeve port that opens to the bore and (ii) a third sleeve port that opens to the bore. The spool may be further formed to include a spool groove in an outer surface of the spool. The spool may also be configured to move with the first diaphragm during at least a portion of the stroke of the first diaphragm such that, when the first diaphragm reaches the second end-of-stroke position, the spool groove fluidly couples the second sleeve port to the third sleeve port to cause the first pilot signal to be supplied to the cut-off valve via the pilot line.

In some embodiments, the spool may be further formed to include a passageway extending parallel to the longitudinal axis between the first spool port and an end of the spool that extends into the first motive fluid chamber, such that the first spool port is fluidly coupled to the first motive fluid chamber at least when the first diaphragm is in the turndown position. The second sleeve port may be fluidly coupled to an exhaust chamber. The first pilot signal may comprise a pressure that does not exceed a threshold. The second pilot signal may comprise a pressure that exceeds the threshold.

In other embodiments, the first spool port may be fluidly coupled to an exhaust chamber at least when the first diaphragm is in the turndown position. The second sleeve port may be fluidly coupled to the compressed fluid inlet. The first pilot signal may comprise a pressure that exceeds a threshold. The second pilot signal may comprise a pressure that does not exceed the threshold.

In some embodiments, the diaphragm pump may further comprise a second diaphragm that separates a second cavity into a second motive fluid chamber and a second pumped media chamber, where the second diaphragm is coupled to the first diaphragm such that the second diaphragm is configured to move reciprocally with the first diaphragm between the first and second end-of-stroke positions, and where the second diaphragm is further configured to stroke from the second end-of-stroke position to first end-of-stroke position in response to compressed fluid being communicated from the compressed fluid inlet to the second motive fluid chamber. The sleeve may be further formed to include a second sleeve port that opens to the bore, the second sleeve port being fluidly coupled to the cut-off valve via the pilot line. The spool may be further formed to include a second spool port, where the spool is also configured to move with the second diaphragm during at least a portion of the stroke of the second diaphragm such that the spool slides relative to the sleeve and, when the second diaphragm reaches the turndown position that is between the first and second end-of-stroke positions, the second spool port aligns with the second sleeve port to cause the second pilot signal to be supplied to the cut-off valve via the pilot line.

In some embodiments, the spool may couple the second diaphragm to the first diaphragm such that the second diaphragm is configured to move reciprocally with the first diaphragm between the first and second end-of-stroke positions. The second diaphragm may engage the spool during at least a portion of the stroke of the first diaphragm to cause the spool to slide relative to the sleeve. The first diaphragm may engage the spool during at least a portion of the stroke of the second diaphragm to cause the spool to slide relative to the sleeve. The spool may be further formed to include (i) a first passageway extending parallel to the longitudinal axis between the first spool port and a first end of the spool that extends into the first motive fluid chamber, such that the first spool port is fluidly coupled to the first motive fluid chamber at least when the first and second diaphragms are in the turndown position, and (ii) a second passageway extending parallel to the longitudinal axis between the second spool port and a second end of the spool that extends into the second motive fluid chamber, such that the second spool port is fluidly coupled to the second motive fluid chamber at least when the first and second diaphragms are in the turndown position.

According to another aspect, a diaphragm pump may comprise a diaphragm that separates a cavity into a motive fluid chamber and a pumped media chamber, where the diaphragm is configured to stroke from a first end-of-stroke position to a second end-of-stroke position in response to compressed fluid being communicated from a compressed fluid inlet to the motive fluid chamber. The diaphragm pump may further comprise a cut-off valve configured to communicate compressed fluid from the compressed fluid inlet to the motive fluid chamber in response to receiving a first pilot signal and resist communication of compressed fluid from the compressed fluid inlet to the motive fluid chamber in response to receiving a second pilot signal. The diaphragm pump may further comprise a sleeve formed to include a bore extending along a longitudinal axis, a first sleeve port that opens to the bore, and a second sleeve port that opens to the bore, where the second sleeve port being fluidly coupled to the cut-off valve via a pilot line. The diaphragm pump may further comprise a spool supported in the bore of the sleeve and formed to include a spool groove in an outer surface of the spool, where the spool is configured to move with the diaphragm during at least a portion of the stroke of the diaphragm such that the spool slides relative to the sleeve and, when the diaphragm reaches a turndown position that is between the first and second end-of-stroke positions, the spool groove fluidly couples the first sleeve port to the second sleeve port to cause the second pilot signal to be supplied to the cut-off valve via the pilot line. At least one of the sleeve and the spool may be rotatable about the longitudinal axis to adjust a location of the turndown position relative to the first and second end-of-stroke positions.

In some embodiments, the sleeve may be further formed to include a third sleeve port that opens to the bore. The second sleeve port may be positioned between the first and third sleeve ports along the longitudinal axis. The spool may also be configured to move with the diaphragm during at least a portion of the stroke of the diaphragm such that, when the diaphragm reaches the second end-of-stroke position, the spool groove fluidly couples the third sleeve port to the second sleeve port to cause the first pilot signal to be supplied to the cut-off valve via the pilot line. The first sleeve port may be fluidly coupled to the compressed fluid inlet. The third sleeve port may be fluidly coupled to an exhaust chamber. The first pilot signal may comprise a pressure that does not exceed a threshold. The second pilot signal may comprise a pressure that exceeds the threshold. The first sleeve port may be fluidly coupled to an exhaust chamber. The third sleeve port may be fluidly coupled to the compressed fluid inlet. The first pilot signal may comprise a pressure that exceeds a threshold. The second pilot signal may comprise a pressure that does not exceed the threshold. The second sleeve port may include a sidewall disposed at an acute angle to a circumference of the sleeve. The spool groove may include a sidewall disposed at an acute angle to a circumference of the spool.

According to yet another aspect, a diaphragm pump may comprise a diaphragm that separates a cavity into a motive fluid chamber and a pumped media chamber, where the diaphragm is configured to stroke from a first end-of-stroke position to a second end-of-stroke position in response to compressed fluid being communicated from a compressed fluid inlet to the motive fluid chamber. The diaphragm pump may further comprise a cut-off valve configured to communicate compressed fluid from the compressed fluid inlet to the motive fluid chamber in response to receiving a first pilot signal and resist communication of compressed fluid from the compressed fluid inlet to the motive fluid chamber in response to receiving a second pilot signal. The diaphragm pump may further comprise a sleeve formed to include a bore extending along a longitudinal axis and a plurality of sleeve ports spaced apart along the longitudinal axis, where a selected one of the plurality of sleeve ports is configured to provide fluid communication between the bore and a pilot line fluidly coupled to the cut-off valve, and where all but the selected one of the plurality of sleeve ports are blocked to resist fluid communication between the bore and the pilot line. The diaphragm pump may further comprise a spool supported in the bore of the sleeve and formed to include a spool port, where the spool is configured to move with the diaphragm during at least a portion of the stroke of the diaphragm such that the spool slides relative to the sleeve and, when the diaphragm reaches a turndown position that is between the first and second end-of-stroke positions, the spool port aligns with the selected one of the plurality of sleeve ports to cause the second pilot signal to be supplied to the cut-off valve via the pilot line. In some embodiments, a location of the turndown position relative to the first and second end-of-stroke positions is dependent upon which of the plurality of sleeve ports is selected.

In some embodiments, a plurality of removable plugs may be positioned in all but the selected one of the plurality of sleeve ports. The diaphragm pump may further comprise a manifold slidable relative to the sleeve along the longitudinal axis, the manifold being configured to cover all but the selected one of the plurality of sleeve ports.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring now toFIGS. 1 and 2, one illustrative embodiment of a diaphragm pump10is shown. The pump10ofFIGS. 1 and 2is illustratively embodied as an air-operated double diaphragm pump. It is contemplated that, in other embodiments, the pump10might be embodied as another type of diaphragm pump (or even another type of positive displacement pump). In the illustrative embodiment, the pump10has a housing12that defines a cavity14and a cavity16. The housing12is illustratively comprised of three sections coupled together by fasteners. As best seen inFIG. 2, the cavities14,16of the pump10are each separated by a respective flexible diaphragm18,20into a respective pumped media chamber22,24and a respective motive fluid chamber26,28. The diaphragms18,20are interconnected by a shaft30, such that when the diaphragm18is moved to increase the volume of the associated pumped media chamber22, the other diaphragm20is simultaneously moved to decrease the volume of the associated pumped media chamber24, and vice versa.

The shaft30illustrated inFIG. 2is a reciprocating diaphragm link rod having a fixed length, such that the diaphragms18,20move reciprocally together with the shaft30. The shaft30and diaphragms18,20move back and forth a fixed distance that defines a stroke. The fixed distance is determined by the geometry of the pump10, the shaft30, the diaphragms18,20, and other components of the pump10. A stroke is defined as the travel path of the shaft30between end-of-stroke positions. Movement of the shaft30from one end-of-stroke position to the other end-of-stroke position and back defines a cycle of operation of the shaft30(i.e., a cycle includes two consecutive strokes).

The pump10includes an inlet32for the supply of a compressed fluid (e.g., compressed air, another pressurized gas, hydraulic fluid, etc.) and a main valve34for alternately supplying the compressed fluid to the motive fluid chambers26,28to drive reciprocation of the diaphragms18,20and the shaft30. The main valve34is fluidly coupled between the inlet32and the motive fluid chambers26,28. When the main valve34supplies compressed fluid to the motive fluid chamber26(while in a position60), the main valve34places an exhaust assembly36in communication with the other motive fluid chamber28to permit fluid to be expelled therefrom. Conversely, when the main valve34supplies compressed fluid to the motive fluid chamber28(while in a position61), the main valve34places the motive fluid chamber26in communication with the exhaust assembly36. In the illustrative embodiment of the pump10, movement of the main valve34between the positions60,61is controlled by a pilot valve35(shown diagrammatically inFIGS. 5-7). As such, by controlling movement of the main valve34, the pilot valve35of the pump10controls the supply of compressed fluid to the motive fluid chambers26,28.

As seen inFIGS. 5-7, the pilot valve35is illustratively embodied as a directional control valve having a spool42movable between a plurality of positions to selectively fluidly couple a plurality of ports formed in the pilot valve35to one another. The pilot valve35is positioned between the cavities14,16such that the spool42extends into each of the cavities14,16, as shown inFIGS. 5-7. As the diaphragms18,20move in unison with the shaft30between the end-of-stroke positions, the diaphragms alternately contact the spool42, causing the spool42to move between its positions such that the pilot valve35either communicates compressed fluid to a pilot chamber76of the main valve34or exhausts the pilot chamber76to the exhaust assembly36.

The exhaust assembly36of the pump10includes an exhaust chamber50and a muffler52that is received in the exhaust chamber50. In the illustrative embodiment, the main valve34alternately couples one of the motive fluid chambers26,28(whichever of the motive fluid chambers26,28is not being supplied with compressed fluid by the main valve34) to the exhaust assembly36to allow any fluid in that motive fluid chamber26,28to be vented to the atmosphere. It is contemplated that, in other embodiments, the pump10might use other mechanisms to selectively couple the motive fluid chambers26,28to the exhaust assembly36(e.g., “quick dump check valves” positioned between the main valve34and the motive fluid chambers26,28).

During operation of the pump10, as the main valve34, the pilot valve35, and the exhaust assembly36cooperate to effect the reciprocation of the diaphragms18,20and the shaft30, the pumped media chambers22,24alternately expand and contract to create respective low and high pressure within the respective pumped media chambers22,24. The pumped media chambers22,24each communicate with a pumped media inlet38that may be connected to a source of fluid to be pumped (also referred to herein as “pumped media”) and also each communicate with a pumped media outlet40that may be connected to a receptacle for the fluid being pumped. Check valves (not shown) ensure that the fluid being pumped moves only from the pumped media inlet38toward the pumped media outlet40. For instance, when the pumped media chamber22expands, the resulting negative pressure draws fluid from the pumped media inlet38into the pumped media chamber22. Simultaneously, the other pumped media chamber24contracts, which creates positive pressure to force fluid contained therein to the pumped media outlet40. Subsequently, as the shaft30and the diaphragms18,20move in the opposite direction, the pumped media chamber22will contract and the pumped media chamber24will expand (forcing fluid contained in the pumped media chamber24to the pumped media outlet40and drawing fluid from the pumped media inlet38into the pumped media chamber24).

Referring now toFIGS. 3-5, the shaft30and the diaphragms18,20are shown diagrammatically in various positions during a stroke of the pump10. Specifically, the shaft30and the diaphragms18,20are shown near a left end-of-stroke position (FIG. 3), mid-stroke (FIG. 4), and in a right end-of-stroke position (FIG. 5). Fluid connections between components included in the pump10are generally depicted by lines, and the directions of compressed fluid flow between the components of the pump10are generally indicated by arrowheads on those lines.

As seen inFIGS. 3-5, a cut-off valve54is fluidly coupled between the inlet32and the main valve34. The cut-off valve54is configured to selectively resist communication of compressed fluid from the inlet32to the main valve34(and, hence, to either of the motive fluid chambers26,28) in response to receiving a particular pilot signal. As described in more detail below, this pilot signal is supplied by an air savings device56that includes a spool57and a sleeve58. One of the spool57and the sleeve58is rotatable relative to the other of the spool57and the sleeve58to adjust at least one “turndown” position at which the air savings device56supplies the particular pilot signal to the cut-off valve54.

Referring now toFIG. 3, the main valve34supplies compressed fluid to the motive fluid chamber28as the shaft30and the diaphragms18,20move away from the one end-of-stroke position and toward the other end-of-stroke position. Specifically, compressed fluid is communicated from the inlet32to a port64of the cut-off valve54, from the port64to a port65of the cut-off valve54fluidly coupled to the port64, from the port65to a port62of the main valve34via a conduit67, from the port62to a port66of the main valve34fluidly coupled to the port62, and from the port66to the motive fluid chamber28via a conduit69. Additionally, the main valve34vents any fluid contained in the motive fluid chamber26to the exhaust assembly36as shown inFIG. 3. Specifically, compressed fluid is communicated from the motive fluid chamber26to a port68of the main valve34via a conduit71, from the port68to a port70of the main valve34fluidly coupled to the port68, and from the port70to the exhaust assembly36via a conduit72.

The main valve34is shown in the position61inFIG. 3. In the position61, as well as the position60and all other positions of the main valve34between the positions60,61, compressed fluid is communicated from the inlet32to a pressure chamber74of the main valve34via conduits75,77. Compressed fluid is illustratively communicated to the pressure chamber74at a constant pressure. A pressure regulator (not shown) may be fluidly coupled between the inlet32and the pressure chamber74to regulate the compressed fluid pressure communicated to the pressure regulator so that the constant compressed fluid pressure is communicated to the pressure chamber74. In some embodiments, the constant compressed fluid pressure communicated to the pressure chamber74is of a smaller magnitude than the compressed fluid pressure supplied from the inlet32. In other embodiments, compressed fluid at a variable pressure may be communicated to the pressure chamber74.

In any case, the pilot chamber76of the main valve34positioned opposite the pressure chamber74is fluidly coupled to the exhaust assembly36in the position61to communicate compressed fluid contained in the pilot chamber76to the exhaust assembly36as shown inFIG. 3(i.e., so the pressure in the pilot chamber76is approximately at atmospheric pressure). Specifically, compressed fluid in the pilot chamber76is communicated to a port79of the pilot valve35via conduit80, from the port79to a port81of the pilot valve35fluidly coupled to the port79, and from the port81to the exhaust assembly36via conduits83,72. The pilot valve35is used to control the pressure differential between the pressure chamber74and the pilot chamber76of the main valve34to cause the main valve34to move between the positions60,61.

The spool42of the pilot valve35extends into each of the motive fluid chambers26,28as shown inFIG. 3. The spool42of the pilot valve35is spaced apart from each of the diaphragms18,20such that the port79is fluidly coupled to the port81and communication between a port84of the pilot valve35and the port79is resisted. The port84receives compressed fluid pressure from the inlet32via conduits75,85. As shown inFIG. 3, the pilot valve35fluidly couples the pilot chamber76to atmospheric pressure through the exhaust assembly36. As shown inFIG. 5, the pilot valve35fluidly couples the pilot chamber76to compressed fluid pressure communicated to the port84when the main valve34is in the position60.

The cut-off valve54is fluidly coupled to the inlet32, the main valve34, and the air savings device56as shown inFIG. 3. The cut-off valve54is illustratively embodied as a normally-closed valve that fluidly couples the inlet32to the main valve34. As such, the cut-off valve54is also configured to communicate compressed fluid from the inlet32to the motive fluid chamber28through the main valve34. More specifically, the cut-off valve54is configured to communicate compressed fluid from the inlet32to the motive fluid chamber28prior to a particular pilot signal being supplied to the cut-off valve54(seeFIG. 3), or once a different pilot signal is supplied to the cut-off valve54from the air savings device56(seeFIG. 5).

The air savings device56extends into each of the motive fluid chambers26,28such that the spool57contacts the diaphragm18and is spaced-apart from the diaphragm20as shown inFIG. 3. When the shaft30and the diaphragms18,20move from the one end-of-stroke position toward the other end-of-stroke position as shown inFIGS. 3-5, the spool57moves with the diaphragm18and slides relative to the sleeve58. Once the shaft30and the diaphragms18,20attain the other end-of-stroke position and begin to move back toward the one end-of-stroke position, the spool57contacts the diaphragm20and is spaced-apart from the diaphragm18.

With reference toFIGS. 3 and 6, the air savings device56is shown inside the pump10as indicated above (seeFIG. 3) and outside the pump10(seeFIG. 6). In each ofFIGS. 3 and 6, the spool57is shown supported in a bore59formed in the sleeve58. The bore59extends along a longitudinal axis63, and the spool57is configured to slide relative to the sleeve58along the longitudinal axis63when the air savings device56is positioned inside the pump10. When positioned within the housing12of the pump10, the sleeve58may be supported such that the sleeve58is rotatable about the longitudinal axis63. In some embodiments, the spool57may be constrained from rotating with the sleeve58about the longitudinal axis63when the air savings device56is positioned inside the housing12. For example, the housing12may be formed to include a keyed feature (not shown), and the spool57may be formed to include a keyed feature73complementary to the keyed feature of the housing12. The keyed feature of the housing12and the keyed feature73are configured to mate with one another to resist rotation of the spool57about the longitudinal axis63. In other embodiments, the spool57may be rotatable about the axis63, and the sleeve58may be constrained from rotating with the spool57about the axis63when the air savings device56is positioned inside the housing12.

Referring again toFIGS. 3 and 6, the sleeve58is formed to include a sleeve port80athat opens into the bore59through a segment86aof the sleeve58, and a sleeve port80bthat opens into the bore59through a segment86bof the sleeve58opposite the segment86a. The sleeve ports80a,80bare substantially identical, except that portions of the sleeve ports80a,80bare spaced apart from one another along the length L1of the sleeve58as shown inFIGS. 3 and 6. The sleeve ports80a,80bincludes sidewalls89a,89b, respectively, disposed at acute angles to the circumference of the sleeve58. Additionally, the spool57is formed to include a spool port82athat extends through a segment90aof an outer surface110of the spool57, and a spool port82bthat extends through a segment90bof the outer surface110opposite the segment90a. The spool ports82a,82bare substantially identical, except that portions of the spool ports82a,82bare spaced apart from one another along the length L2of the spool57as shown inFIGS. 3 and 6.

As best seen inFIGS. 3-5, the spool57is formed to include a passageway92extending parallel to the longitudinal axis63between the spool port82aand an end94of the spool57that contacts the diaphragm18. The spool57is also formed to include a passageway96extending parallel to the longitudinal axis63between the spool port82band an end98of the spool57opposite the end94. The passageways92,96are not fluidly coupled to one another, and no compressed fluid is communicated between the passageways92,96during operation of the pump10. The passageway92is configured to fluidly couple the motive fluid chamber26to the spool port82aat least momentarily when compressed fluid is supplied to the motive fluid chamber26in a turndown position as suggested inFIG. 5. The passageway96is configured to fluidly couple the motive fluid chamber28to the spool port82bat least momentarily when compressed fluid is supplied to the motive fluid chamber28in a second turndown position as suggested inFIG. 3.

The spool ports82a,82bare spaced apart from the sleeve ports80a,80bas shown inFIG. 3. As the shaft30and the diaphragms18,20move toward the pumped media chamber24, engagement between the spool57and the diaphragm18causes the spool57to slide through the bore59of the sleeve58, thereby advancing the spool ports82a,82btoward the sleeve ports80a,80b. As discussed below with regard toFIG. 4, the spool port82band the sleeve port80balign at the second turndown position which causes the pilot signal to be supplied to the cut-off valve54.

Again referencingFIGS. 3 and 6, the sleeve58is formed to include sleeve ports100a,102athat each open into the bore59through a segment103aof the sleeve58. Additionally, the sleeve58is formed to include sleeve ports100b,102bthat each open into the bore59through a segment103bof the sleeve58opposite the segment103a. The sleeve ports100a,102aare positioned between the sleeve ports80a,80band an end104of the sleeve58, and the sleeve ports100b,102bare positioned between the sleeve ports80a,80band an end106of the sleeve58opposite the end104. The sleeve port100bis positioned in closer proximity to the sleeve ports80a,80bthan the sleeve port102b, and the sleeve port100ais positioned in closer proximity to the sleeve ports80a,80b, than the sleeve port102a. As discussed below with regard toFIG. 5, the sleeve ports100a,102acooperate with a spool groove108formed in the spool57to fluidly couple the cut-off valve54to the exhaust assembly36to supply a pilot signal to the cut-off valve54when the shaft30and the diaphragms18,20reach the other end-of-stroke position. Conversely, when the shaft30and the diaphragms18,20move in the opposite direction to the one end-of-stroke position, the sleeve ports100b,102bcooperate with the spool groove108to fluidly couple the cut-off valve54to the exhaust assembly36to again supply a pilot signal to the cut-off valve54.

The spool groove108is formed in the outer surface110of the spool57as best seen inFIGS. 6-8. The spool groove108is spaced apart from the spool ports82a,82balong the outer surface110, and the spool groove108is positioned substantially midway between the ends94,98of the spool57. The spool groove108fluidly couples the sleeve ports100a,102ato one another to supply a pilot signal to the cut-off valve54as indicated above when the shaft30reaches the other end-of-stroke position. Similarly, the spool groove108fluidly couples the sleeve ports100b,102bto one another to supply a pilot signal to the cut-off valve54as indicated above when the shaft30reaches the one end-of-stroke position.

As seen inFIGS. 3-5, each of the sleeve ports80a,80bis fluidly coupled to the cut-off valve54. Specifically, the sleeve port80ais fluidly coupled to the cut-off valve54via conduits107,109, and the sleeve port80bis fluidly coupled to the cut-off valve54via conduits107,109,111. The fluid connection between the sleeve port80aand the cut-off valve54(i.e., through conduits107,109) and between the sleeve port80band the cut-off valve54(i.e., through conduits107,109,111) may be achieved through the use of a single fluid line (i.e., for each of the sleeve ports80a,80b), which is referred to herein as a pilot line. Each of the sleeve ports100aand100bis also fluidly coupled to the cut-off valve54. Specifically, the sleeve port100ais fluidly coupled to the cut-off valve54via conduits107,113, and the sleeve port100bis fluidly coupled to the cut-off valve54via conduits107,115. Each of the sleeve ports102aand102bis fluidly coupled to the exhaust assembly36. Specifically, the sleeve port102ais fluidly coupled to the exhaust assembly36via conduits117,119,72, and the sleeve port102bis fluidly coupled to the exhaust assembly36via conduits117,121,72.

ReferencingFIGS. 3 and 6yet again, the positioning of the spool57relative to the sleeve58as shown inFIG. 3(i.e., while the air savings device56is positioned inside the housing12) is approximated inFIG. 6(i.e., while the air savings device56is positioned outside the housing12). The spool57has not yet advanced through the bore59such that the spool port82band the sleeve port80bare aligned. As such, the shaft30and the diaphragms18,20have not yet reached the second turndown position, and the pilot signal has yet to be supplied to the cut-off valve54.

With reference toFIGS. 4 and 7, the positioning of the spool57relative to the sleeve58as shown inFIG. 4(i.e., while the air savings device56is positioned inside the housing12) is approximated inFIG. 7(i.e., while the air savings device56is positioned outside the housing12). The shaft30and the diaphragms18,20have reached the second turndown position such that the spool port82bis aligned with the sleeve port80b. Since the end98of the spool57is spaced apart from the motive fluid chamber28(seeFIG. 4), compressed fluid supplied to the motive fluid chamber28flows to the spool port82bvia the passageway96. Alignment of the spool port82band the sleeve port80bcauses compressed fluid to be communicated to the cut-off valve54via the pilot line.

The pilot signal described herein may illustratively include compressed fluid pressure communicated to the cut-off valve54via the pilot line. In the illustrative embodiment, the cut-off valve54resists communication of compressed fluid from the inlet32to the motive fluid chamber28in response to receiving the pilot signal. Movement of the normally-open cut-off valve54to a closed position (which resists communication of compressed fluid from the inlet32to the motive fluid chamber28) may be based on the pressure of the compressed fluid communicated to the cut-off valve54from the pilot line. In the illustrative embodiment, the cut-off valve54moves to the open position when the pressure of the pilot signal exceeds a threshold. In other embodiments, the cut-off valve54may move to the open position when the pressure of the pilot signal falls below a threshold.

As indicated above, the turndown position (i.e., the position where the spool port82baligns with the sleeve port80bor the spool port82aaligns with the sleeve port80a) at which the air savings device56supplies a pilot signal to the cut-off valve54is adjustable. Specifically, by rotating the sleeve58relative to the spool57, the spacing between the ports82b,80band the sleeve ports82a,80amay be increased to increase the distance that the shaft30and the diaphragms18,20move between the end-of-stroke positions before the turndown position is reached, or decreased to decrease the distance that the shaft30and the diaphragms18,20move between the end-of-stroke positions before the turndown position is reached.

With reference toFIGS. 5 and 8, the positioning of the spool57relative to the sleeve58as shown inFIG. 5(i.e., while the air savings device56is positioned inside the housing12) is approximated inFIG. 8(i.e., while the air savings device56is positioned outside the housing12). The pilot valve35contacts the diaphragm18to cause the main valve34to move from the position61to the position60, thereby causing compressed fluid from the inlet32to be communicated to the motive fluid chamber26while compressed fluid contained in the motive fluid chamber28is vented through the main valve34to the exhaust assembly36. As such, the shaft30and the diaphragms18,20are shown in the other end-of-stroke position inFIGS. 5 and 8.

In the other end-of-stroke position shown inFIGS. 5 and 8, the groove108formed in the spool57aligns with each of the sleeve ports100a,102a. The groove108fluidly couples the sleeve ports100a,102ato one another so that the compressed fluid communicated to the cut-off valve54is exhausted through the exhaust assembly36. More specifically, compressed fluid flows from the cut-off valve54to the sleeve port100afluidly coupled to the cut-off valve54, from the sleeve port100ato the sleeve port102avia the groove108, and from the sleeve port102ato the exhaust assembly36. Exhausting of the cut-off valve54causes a pilot signal to be supplied to the cut-off valve54from the sleeve port100avia the pilot line. The pilot signal illustratively includes fluid communicated to the cut-off valve54at approximately atmospheric pressure.

In response to receiving the pilot signal via the pilot line, the cut-off valve54opens to communicate compressed fluid from the inlet32to the motive fluid chamber26through the main valve34. In the illustrative embodiment, the cut-off valve54closes in response to the pressure of the pilot signal falling below a threshold. In other embodiments, the cut-off valve54may close in response to the pressure of the pilot signal exceeding a threshold.

Up to this point, the turndown positions have been described as coinciding with the communication of one pilot signal to the cut-off valve54, and the end-of-stroke positions have been described as coinciding with the communication of another pilot signal to the cut-off valve54. It should be appreciated that in other embodiments, the compressed fluid pressures associated with the turndown and end-of-stroke positions may be reversed. More specifically, the initial pilot signal may include fluid at atmospheric pressure and the subsequent pilot signal may include compressed fluid pressure from one of the motive fluid chambers26,28. As such, fluid at atmospheric pressure may be communicated from one of the sleeve ports80a,80bto the cut-off valve54when one of the turndown positions is reached, and compressed fluid pressure from one of the motive fluid chambers26,28may be communicated from one of the sleeve ports100a,100bto the cut-off valve54when one of the end-of-stroke positions is reached. In such embodiments, the pressure of the initial pilot signal may not exceed the threshold, and the pressure of the subsequent pilot signal may exceed the threshold.

Although the air savings device56is positioned in the housing12such that the air savings device56is spaced apart from and extends parallel to the shaft30as shown inFIGS. 3-5, it should be appreciated that in other embodiments, the shaft30may act as the sleeve58, and the spool57may be positioned in a bore (not shown) extending through the shaft. The spool57may couple the diaphragms18,20to one another so that the diaphragms18,20reciprocate together between the end-of-stroke positions.

Referring now toFIG. 9, an air savings device256for use in a pump210is shown that is similar in many respects to the air savings device56used in the pump10shown inFIGS. 1-8and described herein. Accordingly, similar reference numbers (in the200series inFIG. 9) indicate features that are similar in structure and operation between the air savings devices56,256and the pumps10,210. The descriptions of the air savings device56and the pump10are hereby incorporated by reference to apply to the air savings device256and the pump210, except in instances when it conflicts with the specific description and drawings of the air savings device256and the pump210.

Unlike the spool57of the air savings device56, the spool257of the air savings device256is not formed to include passageways extending through the ends294,298of the spool257. The spool257is formed to include grooves297a,297bin an outer surface219of the spool257that are positioned opposite of one another. The spool grooves297a,297binclude sidewalls299a,299b, respectively, disposed at an acute angle to a circumference of the spool57. Further unlike the sleeve58of the air savings device56, the sleeve258of the air savings device256is formed to include single sleeve ports201c,201dopening into the bore259and positioned opposite of one another. The sleeve port201cis positioned between the sleeve port280aand the end204of the sleeve258, and the sleeve port201dis positioned between the sleeve port280band the end204of the sleeve258. Further still unlike the sleeve58of the air savings device56, the sleeve258of the air savings device256is formed to include single sleeve ports202c,202dopening into the bore259and positioned opposite of one another. The sleeve port202cis positioned between the sleeve port280aand the end206of the sleeve258, and the sleeve port202dis positioned between the sleeve port280band the end206of the sleeve258.

When the air savings device256is installed in the pump210, the sleeve ports280a,280bare fluidly coupled to the cut-off valve254via the pilot lines, the sleeve ports201c,201dare fluidly coupled to the inlet232, and the sleeve ports202c,202dare fluidly coupled to the exhaust assembly236. As the air savings device256moves with the diaphragms218,220to a turndown position between the end-of-stroke positions, one of the spool grooves297a,297bfluidly couples one of the sleeve ports201c,201dto one of the sleeve ports280a,280bto cause a pilot signal to be supplied to the cut-off valve254via one of the pilot lines. Similar to the air savings device56, the air savings device256permits the location of the turndown position to be adjusted. Specifically, at least one of the sleeve258and the spool257is rotatable about the longitudinal axis263to adjust the location of the turndown position relative to the end-of-stroke positions. Once the diaphragms218,220reach the end-of-stroke positions, one of the spool grooves297a,297bfluidly couples one of the sleeve ports202c,202dto one of the sleeve ports280a,280bto cause another pilot signal to be supplied to the cut-off valve254via one of the pilot lines.

In the illustrative embodiment, the initial pilot signal supplied to the cut-off valve254comprises a pressure that exceeds the threshold of the cut-off valve254(i.e., similar to the cut-off valve54). The subsequent pilot signal supplied to the cut-off valve254comprises a pressure that does not exceed the threshold of the cut-off valve254(i.e., similar to the cut-off valve54).

In other embodiments, when the air savings device256is installed in the pump210as indicated above, the sleeve ports201c,201dmay be coupled to the exhaust assembly236and the sleeve ports202c,202dmay be coupled to the inlet232. As such, the initial pilot signal supplied to the cut-off valve254comprises a pressure that does not exceed the threshold, and the subsequent pilot signal supplied to the cut-off valve254comprises a pressure that exceeds the threshold.

Referring now toFIG. 10, an air savings device356for use in a pump310is shown that is similar in many respects to the air savings device56used in the pump10shown inFIGS. 1-8and described herein, and also to the air savings device256used in the pump210shown inFIG. 9and described herein. Accordingly, similar reference numbers (in the300series inFIG. 10) indicate features that are similar in structure and operation between the air savings devices56,256,356and the pumps10,210,310. The descriptions of the air savings device56and the pump10, as well as the air savings device256and the pump210, are hereby incorporated by reference to apply to the air savings device356and the pump310, except in instances when it conflicts with the specific description and drawings of the air savings device356and the pump310.

As shown inFIG. 10, the sleeve358of the air savings device356is formed to include a plurality of sleeve ports333aspaced apart from one another along the longitudinal axis363. The sleeve358is also formed to include a plurality of sleeve ports333bspaced apart from one another along the longitudinal axis363and positioned opposite the sleeve ports333a. Each of the ports333a,333bopens into the bore359as shown inFIG. 10. The sleeve358is further formed to include sleeve ports300c,300dpositioned opposite one another and sleeve ports302c,302dpositioned opposite one another.

The spool357of the air savings device356is formed to include spool ports382a,382bpositioned opposite one another in the outer surface319as suggested inFIG. 10. Similar to the spool57of the air savings device56, the spool357is formed to include the passageway392extending along the axis363through the end394of the spool357and the passageway396extending along the axis363through the opposite end398of the spool357.

When the air savings device356is installed in the pump310, the sleeve ports300c,300dare fluidly coupled to the pilot lines of the cut-off valve354, and the sleeve ports302c,302dare fluidly coupled to the exhaust assembly336. A selected one of the plurality of ports333ais configured to provide fluid communication between the bore359and the pilot line via the sleeve port300c(i.e., as the diaphragms318,320move toward one end-of-stroke position), and a selected one of the ports333bis configured to provide fluid communication between the bore359and the pilot line via the sleeve port300d(i.e., as the diaphragms318,320move toward the other of end-of-stroke position). For each of the pluralities of ports333a,333b, all but the selected one of the plurality of ports333a,333bare blocked to resist fluid communication between the bore359and the pilot lines.

As the spool357of the air savings device356moves with the diaphragms318,320to a turndown position located between the one end-of-stroke position and the other end-of-stroke position, one of the spool ports382a,382baligns with the selected one of one of the pluralities of sleeve ports333a,333bto cause the initial pilot signal to be supplied to the cut-off valve354via one of the pilot lines. The location of the turndown position relative to the one end-of-stroke position and the other end-of-stroke position is dependent upon which one of the pluralities of sleeve ports333a,333bis selected.

As shown inFIG. 10, a plurality of removable plugs339aare positioned in all but the selected one of the sleeve ports333a. A plurality of removable plugs339bmay be positioned in all but the selected one of the sleeve ports333b. In other embodiments, a manifold (not shown) slidable relative to the sleeve358along the longitudinal axis363may be configured to cover all but the selected one of the sleeve ports333aand all but the selected one of the sleeve ports333b.

While certain illustrative embodiments have been described in detail in the figures and the foregoing description, such an illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected. There are a plurality of advantages of the present disclosure arising from the various features of the apparatus, systems, and methods described herein. It will be noted that alternative embodiments of the apparatus, systems, and methods of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of the apparatus, systems, and methods that incorporate one or more of the features of the present disclosure.