EP0824193A2 - Organe de commande hydraulique d'un manostat de système fluidique - Google Patents

Organe de commande hydraulique d'un manostat de système fluidique Download PDF

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Publication number
EP0824193A2
EP0824193A2 EP19970106721 EP97106721A EP0824193A2 EP 0824193 A2 EP0824193 A2 EP 0824193A2 EP 19970106721 EP19970106721 EP 19970106721 EP 97106721 A EP97106721 A EP 97106721A EP 0824193 A2 EP0824193 A2 EP 0824193A2
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EP
European Patent Office
Prior art keywords
pressure
piston
fluidic
blocker
shuttle
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Withdrawn
Application number
EP19970106721
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German (de)
English (en)
Inventor
Osvaldo Valdes
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Individual
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Individual
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Publication date
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Publication of EP0824193A2 publication Critical patent/EP0824193A2/fr
Withdrawn legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/02—Stopping, starting, unloading or idling control
    • F04B49/022—Stopping, starting, unloading or idling control by means of pressure

Definitions

  • the present invention relates generally to automatic control of a fluidic pump in a pressurized fluidic pumping system and more specifically to an hydraulic actuator useful for isolating a pressure switch or an electrical switch from system pressure during periods of pump flow greater than a predetermined volumetric flow rate.
  • Fluidic pumping systems such as those presently widely utilized in domestic water supply applications often employ a pressure switch which turns an electrically driven pump on when the system pressure falls below a predetermined cut-in pressure and turns the pump off when the system pressure rises above a predetermined cut-out pressure.
  • Such systems often incorporate a conventional diaphragm tank which includes both pressurized air and system fluid separated by a flexible bladder or other element.
  • Diaphragm tanks are desirable from an operational standpoint as they may reduce cycling of the pump by providing a limited amount of fluidic capacitance in the supply system.
  • Systems of this type may be characterized by supply pressure which varies, depending both on the amount of fluid in the tank as well as the operational state of the pump. Supply pressure variability is generally undesirable from the standpoint of a user.
  • the improved system disclosed therein includes a motor driven pump controlled by a pressure switch mounted to an hydraulic actuator port which is selectively isolated from internal system pressure during periods of consumption demand above a predetermined flow rate.
  • the system advantageously supplies a substantially constant pressure output.
  • pump motor cycling may be reduced significantly and the concomitant reduction in motor life associated therewith avoided.
  • the system obviates the cost and space claim associated with large, short-lived diaphragm tanks, system capacitance being provided by a small hydropneumatic arrangement as disclosed therein.
  • a less complex, inexpensive, improved hydraulic actuator having a selectively isolatable pressure switch port useful for controlling a fluidic pump in a pressurized supply system to deliver fluid at substantially constant pressure is comprised of a generally cylindrical housing having disposed therein a movable shuttle.
  • the housing and shuffle combine to form three collinear piston and cylinder assemblies which cooperate, as a result of opposing hydrodynamic and hydrostatic forces, to isolate the pressure switch port during periods of fluidic flow through the actuator housing above a predetermined threshold volumetric flow rate. Such periods may correspond, for example, to moderate to high consumption.
  • the pump is activated and remains on, supplying fluidic flow to a consumption demand at substantially constant pressure.
  • the shuttle is displaced in the housing permitting communication of system pressure, already above cut-out pressure, to the pressure switch port which deactivates the pump.
  • the actuator may be advantageously used with a fluidic pump and pressure switch in combination with a variety of components, including small hydropneumatic tanks or more conventional diaphragm tanks with or without additional valving.
  • Conventional pressure regulation apparatus may also be employed to limit pressurization of a diaphragm tank or supply system piping if desired.
  • a limited volumetric flow rate orifice at the pressure switch port delays communication of the system pressure to the pressure switch.
  • a pressure tank and the pressure switch are connected to the pressure switch port.
  • the volume in this pressure tank is provided by the system pressure force acting against the force of a spring.
  • the spring acts in turn on a piston adapted to move along a cylinder that is capable of containing a compressed volume.
  • a check valve such as a rubber ring V-seal, is used to discharge the compressed volume to the system pressure when the tank pressure is higher than the system pressure.
  • an electrical switch driven by relative movement of the piston may be substituted for the pressure switch.
  • the electrical switch turns the pump off at a relative piston compression and turns the pump on at a relative piston expansion.
  • a pressure adjustable dial may be connected to the electrical switch for adjusting the relative pressures for turning the pump on and off.
  • the piston can include two elements, the first element having an elongated tee form and the second element having a helicoidal form.
  • a graduated dial having a plurality of wheels is attached to the helicoidal element. The wheels of the graduated dial engage and disengage the electric switch under predetermined conditions.
  • FIG. 1 Shown in FIG. 1 is a schematic, sectional view of an hydraulic actuator housing 10 in accordance with a preferred embodiment of the present invention.
  • Housing 10 is generally cylindrical and includes an inlet 12 , at least one outlet 14 and a system pressure port 16 suitably configured to receive a pressure switch flange or otherwise provide a pressure tight fitting for connection with a pressure switch.
  • the inlet 12 may be conventionally connected to an outlet of a fluidic pump, for example by a threaded connection, and the outlet 14 similarly connected to piping conveying pressurized fluid to a consumption device such as a faucet (not shown).
  • FIG. 2 depicts a schematic, sectional view of an hydraulic actuator shuttle 18 which is sized and configured to be received in close fitting relation within the housing 10 .
  • the cylindrical shuttle 18 cooperates with housing 10 , constituting therewith a plurality of collinear piston and cylinder assemblies, namely sensor assembly 20 , tractor assembly 26 and blocker assembly 32 , as depicted in an assembled actuator 50 shown in FIG. 3B .
  • the sensor assembly 20 includes sensor piston 22 of shuttle 18 , sensor cylinder 24 of housing 10 and sensor seal 38 ;
  • the tractor assembly 26 includes tractor piston 28 of housing 10 , tractor cylinder 30 of shuttle 18 and tractor seal 40 ; and
  • the blocker assembly 32 includes blocker piston 34 of shuttle 18, blocker cylinder 36 of housing 10 and blocker seal 42 .
  • the sensor cylinder 24 also includes an optional longitudinal bypass channel 48 , the purpose of which is discussed in detail below. With the exception of the bypass channel 48 , the sensor, tractor and blocker assemblies 20 , 26 , 32 are substantially symmetrical about respective longitudinal axes 44 , 46 of housing 10 and shuttle 18 .
  • the axes 44 , 46 are substantially collinear and coincident in the assembled state.
  • sensor seal 38 is an O-ring retained by the sensor piston 22
  • tractor seal 40 is a V-seal retained by the tractor piston 28
  • blocker seal 42 is an O-ring retained by the blocker cylinder 36 ; however, other types of seals and retention schemes may be substituted therefore and are considered within the scope of this invention.
  • the shuttle 18 In the assembled state, the shuttle 18 is substantially free to move longitudinally in the housing 10 within a predetermined range, subject primarily to opposing hydrodynamic and hydrostatic forces, as well as seal drag, as will be discussed in greater detail below.
  • the range of motion of shuttle 18 is established by annular seat 60 of sensor cylinder 24 and annular end face 62 of blocker cylinder 36 , which respectively abut portions of annular flow face 64 and annular pressure face 66 of shuttle 18 at shuttle travel limits.
  • FIGS. 3A and 3B schematically depict an hydraulic actuator assembly 50 in two different operational states, in combination with a pressure switch 52 for controlling a pump.
  • FIG. 3A depicts a high flow state in which the shuttle 18 is displaced in a downstream direction in the housing 10 , as shown in the figure, due to the net hydrodynamic forte acting thereon by fluidic flow, shown generally at 68 , entering housing 10 at inlet 12 and exiting at outlet 14 .
  • Any fluid in tractor assembly volume 76 is below system pressure in this state and urges upstream displacement of the shuttle 18 as discussed in further detail below.
  • FIG. 3A depicts a high flow state in which the shuttle 18 is displaced in a downstream direction in the housing 10 , as shown in the figure, due to the net hydrodynamic forte acting thereon by fluidic flow, shown generally at 68 , entering housing 10 at inlet 12 and exiting at outlet 14 .
  • Any fluid in tractor assembly volume 76 is below system pressure in this state and urges upstream displacement of the shuttle 18 as discussed in further detail below.
  • 3B depicts a zero or low flow state below a predetermined volumetric flow rate, in which the shuttle 18 is fully displaced in an upstream direction in the housing, as shown in the figure, due to the net hydrostatic force acting thereon by pressurized fluid in the housing 10 , shown generally at 70 .
  • Pressure switch 52 is conventional in nature, depicted here as being of the normally-closed electrical contact variety.
  • Switch 52 includes a plunger 54 biased by compression spring 56 so that electrical contacts 58 are closed when the pressure of pressure port 16 sensed in pressure switch cavity 72 is less than a predetermined cut-out pressure. Closed contacts 58 may be used to complete an electrical circuit energizing an electric motor connected to a fluidic pump (not shown) providing pressurized fluid to inlet 12 .
  • FIG. 3B a pressurized fluidic system having a system pressure, P s , with no consumption and hence zero flow through the housing 10 .
  • System pressure is uniform throughout the housing 10 , including at inlet 12 , the bypass channel 48 ensuring normalization of system pressure across the sensor assembly 20 .
  • the shuttle 18 is therefore exposed to uniform pressure loading along all external, exposed surfaces including flow face 64 and pressure face 66 .
  • Shuttle 18 is advantageously configured such that surface area exposed to the pressurized fluid 70 at system pressure results in a net upstream longitudinal force, as depicted in the figure, which acts to seat the sensor piston 22 against seat 60 , substantially blocking the inlet 12 to flow.
  • the total area of radial surfaces of shuttle 18 exposed to system pressure from above is greater than the total area of radial surfaces of shuttle 18 exposed to system pressure from below, namely annular flow face 64 , as shown in FIG. 2 .
  • Differential surface area 67 is subject to a lower pressure than system pressure, this lower pressure being reduced further as tractor assembly volume 76 increases during downstream displacement of the shuttle 18.
  • pressure in volume 76 decreases, so too does pressure in pressure switch cavity 72 , being in flow communication therewith by way of a blocker piston vent 74 , preventing cut-out actuation of the pressure switch 52 during shuttle displacement.
  • the net hydrostatic force acting on the shuttle 18 in the upstream direction may be conventionally determined as being approximated by the product of differential area 67 and the differential pressure acting thereon.
  • the hydrodynamic force of the fluidic flow 68 acts to displace the shuttle 18 from seat 60 in a downstream direction as depicted in FIG. 3A .
  • the blocker piston 34 enters the blocker cylinder 36 .
  • Blocker piston 34 , blocker cylinder 36 and blocker seal 42 cooperate to isolate pressure port 16 and volume 76 from rising system pressure as long as the shuttle 18 is so displaced.
  • the volumetric flow rate of the fluidic flow 68 decreases.
  • the hydrodynamic force of the fluidic flow 68 acting on the shuttle 18 is insufficient to displace the shuttle pressure face 66 against blocker cylinder end face 62 and the shuttle 18 migrates in an upstream direction, downwardly in the figure, until the net hydrodynamic and hydrostatic forces acting thereon are balanced.
  • the lower the rate of fluidic flow 68 the more the shuttle 18 is displaced in an upstream direction as depicted in the figure.
  • the blocker piston 38 being displaced in the blocker cylinder 36 a sufficient distance to permit system pressure normalization across the blocker seal 42 , allows communication of system pressure to pressure switch cavity 72 via pressure port 16 .
  • system pressure is greater than cut-out pressure and plunger 54 is displaced against the spring 56 due to the net force acting thereon by the system pressure, the electrical contacts 58 are opened and pump operation ceases.
  • the fluidic system remains pressurized and the pump remains idle until consumption is initiated once again, as previously described.
  • the motion of the shuttle 18 is also subject to seal drag, which is related to friction between the mobile shuttle 18 and the housing 10 caused by compression of seals 38 , 40 , 42 disposed therebetween.
  • seal drag is related to friction between the mobile shuttle 18 and the housing 10 caused by compression of seals 38 , 40 , 42 disposed therebetween.
  • the net hydrostatic force acting on the shuttle 18 in a zero flow condition should be of sufficient magnitude to overcome seal drag so as to reliably abut shuttle flow face 64 against housing seat 60 to prevent continued isolation of the pressure switch port 16 after consumption has terminated resulting in unnecessary operation of the pump.
  • the net hydrostatic force acting on the shuttle 18 at zero flow may be predetermined as desired by selecting the magnitude of the differential area 67 exposed to lower pressure in volume 76 .
  • the tractor assembly 26 may include a vent 74 disposed longitudinally through blocker piston 34 as shown, for example, in FIG. 2 .
  • Vent 74 provides for normalization of pressure between the variably sized volume 76 enclosed by tractor assembly 26 and pressure port 16 . In this manner, the force required to displace the shuffle 18 is not substantially related to the volume 76 within the tractor assembly nor to that within switch cavity 72.
  • a relief valve 78 may be provided which communicates the respective volumes 76 , 80 enclosed by the tractor and blocker assemblies 26 , 32 with system pressure, as shown in FIG. 3A .
  • the relief valve 78 is a U-cup seal; however, any of a variety of relief valve schemes may be incorporated, including a spring loaded ball valve, for example.
  • vent 174 provides for normalization of internal pressure of tractor assembly 126 with ambient. Vent 174 may be advantageously provided through tractor piston 128 and a radial support 102 thereof. No additional relief valving between blocker assembly 132 and system pressure is required for this configuration, as the fluid displaced from blocker assembly volume 180 due to shuttle movement is of insufficient volume to overpressurize a conventional pressure switch or cause considerable resistance to displacement of the shuttle 118 . If desired, however, relief valving to system pressure may be provided in a manner similar to that depicted in FIG. 3A . All other elements and operational characteristics are similar to the preferred embodiment depicted in FIGS. 3A and 3B .
  • the opposing hydrostatic and hydrodynamic forces acting on the shuttle 18 permit the hydraulic actuator assembly 50 to operate in the advantageous manner described.
  • much leeway is afforded in the relative sizing of diameters and longitudinal lengths associated with the sensor, tractor and blocker assemblies 20 , 26 , 32 to achieve a desired operating characteristic; however, some general guidelines are relevant.
  • the diameter of sensor piston 22 is preferably larger than the diameter of tractor piston 28 in sufficient degree to provide proper radial area of flow face 64 upon which hydrodynamic forces primarily act.
  • Pressure loss of the fluidic flow 68 passing through the assembly 50 may also be reduced by using a relatively large sensor piston diameter and small tractor piston diameter to reduce blockage with the shuttle 18 displaced in a downstream direction as shown in FIG. 3A .
  • tractor piston 28 is preferably larger than that of blocker piston 34 to provide sufficient area of pressure face 66 and differential surface 67 upon which hydrostatic closure forces primarily act.
  • an area ratio of sensor piston diameter to tractor piston diameter of about two to one has been found to facilitate force balance operation in an advantageous manner.
  • longitudinal lengths of the sensor piston 22 and sensor cylinder 24 are preferably shorter than those of the tractor piston 28 and tractor cylinder 30 to minimize pressure loss of fluidic flow 68 passing thereby.
  • the length of blocker piston 34 and the placement of blocker seal 42 in the blocker cylinder 36 is predetermined to ensure proper isolation of pressure port 16 from system pressure when the shuttle 18 is displaced in a downstream direction, as shown in FIG. 3A , as well as to ensure proper communication of system pressure to the pressure port 16 when the shuttle 18 is fully displaced in an upstream direction, as shown in FIG. 3B .
  • FIG. 5 depicted is a schematic, block diagram of one embodiment of a preferred fluidic pumping system 84 incorporating the present invention.
  • An electrically driven pump 88 draws or receives fluid from a source 86 , discharging fluidic flow 68 through hydraulic actuator assembly 50 ultimately to consumption 92 . Operation of the pump 88 is controlled by pressure switch 52 selectively isolatable from system pressure as discussed hereinabove.
  • an hydropneumatic tank 90 may be attached to an outlet 114 either connected to or separate from primary outlet 14 of the actuator 50 , to provide fluidic capacitance to the system 84 .
  • tank 90 includes a pocket of gas, such as air, which is compressed by pressurized fluid 70 from actuator 50 .
  • the hydropneumatic tank 90 may also include a self-contained air-injection pumping apparatus for automatically replenishing air within the tank consumed by operation of a fluidic system as disclosed by Valdes.
  • system 84 is applicable to new construction fluidic supply systems, the invention is equally suitable for retrofitting existing systems, for example, of the domestic water supply variety.
  • high, substantially constant pressure output is a desirable supply system characteristic; however, where there exists a concern due to high pressure afforded by system 84 , especially on existing piping or consumption devices in poor condition, system pressure may be suitably limited by addition of a pressure regulator 94 of conventional configuration.
  • the regulator 94 may be advantageously located downstream of pump 88 , for example downstream of actuator 50 , and upstream of any fragile piping 96 . Inclusion of regulator 94 will permit operation of the system 84 with a high pressure output pump 88 with supply piping 96 which may be in poor condition or consumption devices otherwise unable to accommodate high system pressure afforded by the system 84.
  • FIG. 6 depicts a schematic, block diagram of an alternate embodiment of a fluidic pumping system 98 incorporating an hydraulic actuator 150 according to the present invention.
  • An electrically driven pump 188 draws or receives fluid from a source 186 , discharging fluidic flow 168 downstream through hydraulic actuator assembly 150 to consumption 192 . Operation of the pump 188 is controlled by pressure switch 152 selectively isolatable from system pressure as discussed hereinabove.
  • a diaphragm tank 100 may be attached to an outlet 214 of the actuator 50 , to provide fluidic capacitance to the system 98 .
  • diaphragm tank 100 includes pressurized air and system fluid separated by a flexible bladder or may comprise another element, such as an expandable, flexible balloon type enclosure.
  • the tank 100 supplies fluid for consumption to the extent of its fluidic capacity without the need for cycling of the pump 188 .
  • System 98 configured with a diaphragm tank 100 , may also incorporate a conventional pressure regulator 194 to prevent overpressurization of the tank 100 if deemed necessary.
  • the regulator 194 may be disposed between the pump 188 and actuator 150 as shown or alternatively may be disposed between the actuator 150 and the tank 100 to protect the tank 100 from high pressure output of the pump 188 .
  • System 98 may further incorporate a valve 104 , disposed between the actuator 150 and the diaphragm tank 100 , the purpose of the valve 104 being to terminate fluidic flow to the tank 100 at a predetermined system pressure.
  • a valve 104 may be desirable when the actuator 150 is used in combination with a tank 100 having a large fluidic capacitance. Without the valve 104 , the system 98 may exhibit an extended recharge cycle, which is related both to tank capacitance and pump flow versus pressure characteristics. Incorporation of valve 104 acts to isolate the tank 100 from the system 98 at a predetermined pressure, to prevent continued operation of the pump 188 at higher pressures where volumetric flow rate is reduced.
  • shuttdown of the pump 188 will occur soon after isolation of the tank 100 occurs due to closure of valve 104 . Once valve 104 closes, flow within the system 98 decreases rapidly to below a predetermined threshold volumetric flow rate allowing the pressure switch to be exposed to system pressure due to actuation of the hydraulic actuator 150 .
  • FIG. 6A depicts a typical embodiment of a suitable valve 104 which includes a cylindrical housing 106 with a radial wall 108 having a plurality of apertures 110 disposed therethrough.
  • a generally cylindrical movable element 112 disposed within housing 106 is biased away from wall 108 by an adjustable compression spring 120 disposed therebetween.
  • the spring 120 may be adjusted to modify the compression thereof and resultant spring force at valve closure in a conventional manner, for example, by a threaded fastener (not shown).
  • Volume 113 within the movable element 112 , is communicated to ambient through vent 119 passing through wall 108 and isolated from system pressure by seal 121 .
  • flow 168 passes around the element 112 and through the apertures 110 to fill the tank 100.
  • the differential force between system pressure acting on surface area 117 and ambient pressure acting on surface area 115 overcomes the force exerted by spring 120 and the spring 120 is compressed sufficiently, such that movable element annular lip 116 blocks apertures 110 preventing flow therethrough.
  • Flow rate thereafter decreases rapidly in the system to less than a predetermined volumetric flow rate, the shuttle 18 is fully displaced in the upstream direction exposing the pressure switch 152 to system pressure greater than cut-out pressure, and the pressure switch 152 shuts the pump 188 off.
  • the valve 104 remains closed due to the differential pressure thereacross.
  • valve 104 opens automatically, permitting fluid stored in the tank 100 to meet the demand within the capacitance limit of the tank 100 .
  • tank capacitance When tank capacitance is exhausted, system pressure drops below pump cut-out pressure and the pump 188 is turned on by the pressure switch 152 and the cycle begins anew.
  • the cut-out pressure may correspond to partial discharge of the fluid in the tank 100 , in which case the pump 188 is energized sooner.
  • bypass channel 48 in the actuator sensor assembly 20 serves to normalize the pressure across sensor piston 22 when piston flow face 64 is abutting seat 60 as shown in FIG. 3B .
  • the size or cross-sectional area of bypass channel 48 is advantageously configured to permit a predetermined volumetric flow rate of fluid to bypass without displacing the sensor piston 22 . This permits recharging or pressurization of a conventional diaphragm tank 100 or an hydropneumatic tank 90 of the type disclosed in the aforementioned patent to Valdes.
  • the cut-out pressure of the pressure switch 152 , 52 may be set high enough to permit continued operation of the pump 188 , 88 after the shuttle 18 is displaced to abut seat 60 to afford pressurization of the system 98 , 84 to a desired level.
  • the bypass channel 48 may be configured as a small, longitudinal groove in the sensor cylinder 24 as depicted. One or more may be provided depending, for example, on the maximum pressure output of the pump 88 and the desired recharge rate of the hydropneumatic tank 90 . In a typical embodiment, volumetric flow rate through the bypass channel 48 may be about two liters per minute for a system cut-out pressure of fifty pounds per square inch.
  • bypass flow area may be desirable than readily afforded by bypass channel 48 to achieve a desirable recharge rate.
  • one or more apertures 82 disposed through sensor piston 22 may be provided as depicted in FIG. 2 . Inclusion of such apertures 82 understandably reduce the hydrodynamic force acting on the shuttle 18 during periods of fluidic flow while not substantially affecting the net hydrostatic load thereon.
  • the actuator assembly 50 is advantageously configured to facilitate manufacture by injection molding, without the need for costly post-molding machining steps in the manufacture thereof. All pistons, cylinders, vents and seal grooves may be used in the as-molded condition.
  • both housing 10 and shuttle 18 are each molded in a unitary manner of commercially available nylon polymer such as Delrin, a registered trademark of Dupont, although any suitable material may be employed.
  • Housing 10 may also include a split-line, mating radial flange (not shown) disposed longitudinally between tractor piston 28 and blocker cylinder 36 to facilitate installation of the shuttle 18 therein.
  • the performance of the actuator 50 and any pumping system in which the actuator 50 is utilized is not subject to degradation over time, for example, due to relaxation of spring force, or nonlinear spring effects.
  • the improved actuator 50 and fluidic pumping systems incorporating the improved actuator 50 are advantageously applied to a wide variety of uses. Applications include, but are not limited to, primary pressure applications with subterranean or surface fluidic sources and pressure boost applications with municipal or other pressurized water sources.
  • FIG. 7 illustrates another embodiment of the present invention.
  • system 200 includes housing 210 , shuttle 218 , switch 252 and pressure tank 290 .
  • Fluid is introduced into housing 210 from a fluidic pump (not shown) through inlet 212 as discussed hereinabove.
  • Fluid 270 exits housing 210 through outlet 214 as also discussed hereinabove.
  • outlet 214 is at right angles with inlet 212 .
  • System 200 includes sensor piston 222 having annular flow face 264 , tractor piston 228 , blocker pisto n 234 , sensor seal 238 , tractor seal 240 , blocker seal 242 and blocker cylinder 236 .
  • Bypass channel 248 should also be included with the system 200 .
  • Pressure port 216 and pressure switch cavity 272 are connected to pressure switch 252 .
  • Plunger 254 , spring 256 and electrical contacts 258 respectively function in a similar manner as plunger 54 , spring 56 and electrical contacts 58 discussed above in connection with FIGS. 3A and 3B .
  • system 200 includes pressure tank 290 .
  • Pressure tank 290 is preferably designed to contain a volume of fluid between two pressure ranges, for example between a cut-in pressure and a cut-out pressure. Volume is provided to pressure tank 290 by the system pressure force acting against the force of pressure tank spring 296 .
  • Spring 296 in turn acts on pressure tank piston 292 slidably engaged with pressure tank cylinder 294 . Air within cylinder 294 at the piston spring side is communicated to the atmosphere through the orifice 295 .
  • Pressure tank seal 298 is attached to pressure tank piston 296 and is a dynamic seal.
  • Check valve 288 communicates the compressed volume within pressure tank 290 to the system pressure when the pressure of the compressed volume is higher than the system pressure.
  • the check valve 288 allows immediate discharge of compressed volume to produce instant pump reaction.
  • Check valve 288 such as a rubber ring V-seal, is a one-way valve that prevents the entrance of fluid into pressure tank 290 .
  • the system 200 shown in FIG. 7 is utilized to delay communication of the system pressure to the pressure switch.
  • pressure port 216 has a limited volumetric flow rate orifice that can delay communication of the system pressure to the pressure switch once blocker assembly 232 is opened to communicate the system pressure to the pressure switch.
  • volumetric flow carrying system pressure must fill pressure tank 290 up to a cut-off pressure before pressure switch 252 disconnects the pump. This allows a lapsed time between demand reaching a less than a predetermined volumetric flow rate and actual pump shut down.
  • the limited volumetric flow rate orifice 215 has a cleaning wire 217 that is moved by shuttle 218 displacement. Said cleaning wine 217 is kept against the shuttle by spring 219 .
  • FIG. 8 illustrates yet another alternative embodiment of the present invention.
  • a pressure tank is connected to the pressure port.
  • System 300 includes actuator housing 310 , shuttle 318 , pressure tank 390 and switch 352 .
  • Fluid is introduced into housing 310 from a fluidic pump (not shown) through inlet 312 as discussed hereinabove. Fluid 370 exits housing 310 through outlet 314 as also discussed hereinabove. As shown in FIG. 8 , outlet 314 is at right angles with inlet 312 .
  • System 300 includes sensor piston 322 having annular flow face 364 , tractor piston 328 , blocker piston 334 , sensor seal 338 , tractor seal 340 , blocker seal 342 and blocker cylinder 336 .
  • Bypass channel 348 should also be included with the system 300 .
  • the pressure tank 390 of system 300 is preferably designed to contain a volume of fluid between two pressure ranges, for example between a cut-in pressure and a cut-out pressure. Volume is provided to pressure tank 390 by the system pressure force acting against the force of pressure tank spring 396 .
  • Spring 396 in turn acts on pressure tank piston 392 , which is slidably engaged with pressure tank cylinder 394 , preferably between two pressure readings, such as a cut-in pressure and a cut-off pressure to provide for a compressed volume of fluid.
  • the volume in the pressure tank is provided by the system pressure force acting on the force of a spring.
  • the spring acts on a piston adapted to move along a cylinder that is capable of containing the compressed volume.
  • a pressure tank seal 398 may be positioned between the pressure tank cylinder 394 and the pressure tank piston 392 as shown in FIG. 8 .
  • the pressure tank seal can be a rubber V-seal or the like.
  • Pressure tank seal is dynamic in that it moves with pressure tank piston 392 relative to the pressure tank cylinder 394 .
  • a check valve 388 such as a rubber ring V-seal, is used to communicate the compressed volume within pressure tank 390 to the system pressure when the pressure of the compressed volume is higher than the system pressure.
  • the check valve 388 allows immediate discharge of compressed volume, while the system pressure reaches the cut-in pressure, thereby producing instant pump reaction.
  • the limited volumetric flow rate orifice 315 of pressure port 316 has a cleaning wire 317 that is moved by shuttle 318 displacement. Said cleaning wire is kept against the shuttle by spring 319 .
  • Check valve 388 such as a rubber ring V-seal, is a one-way valve that prevents the entrance of fluid into pressure tank 390 .
  • Switch 352 having electrical contacts 358 is connected to tank 390.
  • Switch 352 can be a micro-switch or the like.
  • Screw 374 or the like adjusts relative displacement of latch 378 along axle 376 .
  • Latch 378 or the like acts on the button of electrical switch 352 . Therefore, switch 352 is driven by relative mechanical movement of the pressure tank piston 392 through latch 378 so that the electrical switch turns the pump off at a relative piston compression and turns the pump on at a relative piston expansion.
  • the axis of the pressure tank piston 392 displacement is divided into two elements.
  • the first element 408 is integral to the piston 392 and has the form of an elongated tee as shown in FIG. 9 .
  • the second element 410 has a helicoidal form, and is able to rotate at the center of the pressure tank cap 412 .
  • the helicoidal element 410 holds or is connected to the tee 408 .
  • the axial displacement of the pressure tank piston 392 is transformed into a radial movement in the second element.
  • Dial 400 includes a plurality of wheels 402 , whose axes are the same as the axes of the elements 408 , 410 .
  • Wheels 402 are arranged to be able to act on an electric switch 352 .
  • One wheel has an engaging protruding piece 406 that can engage the switch, thereby turning the switch on.
  • the other wheel has a disengaging protruding piece 404 that can disengage the switch, thereby turning the switch off. Both wheels can be adjusted to the graduated dial 400 , and once adjusted, will move together with the dial.
  • the pressure tank piston displacement responds to the amount of compressed volume within the pressure tank 390 and because this volume depends on the actual pressure measured inside the tank, the circular rotation of the graduated dial, together with the wheels, respond to the actual pressure measured inside the tank.
  • the protruding piece of the engaging wheel will engage the electric switch, turning the switch in.
  • the protruding piece of the disengaging wheel will disengage the electric switch, turning the switch off.
  • a pressure adjustment dial may be particularly advantageous for an easy adjustment of cut-in and cut-off pressures.

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EP19970106721 1996-04-23 1997-04-23 Organe de commande hydraulique d'un manostat de système fluidique Withdrawn EP0824193A2 (fr)

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US63687796A 1996-04-23 1996-04-23
US636877 1996-04-23

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0899457A1 (fr) * 1997-08-28 1999-03-03 Jean-Paul Hettler Régulateur hydraulique à débit progressif
EP1111242A1 (fr) * 1999-12-24 2001-06-27 Der-Fan Shen Régulateur de débit pour une pompe à eau
CN106481569A (zh) * 2016-12-16 2017-03-08 浙江美泰泵业科技有限公司 一种智能水泵

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0899457A1 (fr) * 1997-08-28 1999-03-03 Jean-Paul Hettler Régulateur hydraulique à débit progressif
EP1111242A1 (fr) * 1999-12-24 2001-06-27 Der-Fan Shen Régulateur de débit pour une pompe à eau
CN106481569A (zh) * 2016-12-16 2017-03-08 浙江美泰泵业科技有限公司 一种智能水泵
CN106481569B (zh) * 2016-12-16 2024-03-22 浙江美泰泵业科技有限公司 一种智能水泵

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