Classifications

• • 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
  • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
  • F04B39/0005—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00 adaptations of pistons
• • 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
  • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
  • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
  • F04B1/122—Details or component parts, e.g. valves, sealings or lubrication means
  • F04B1/124—Pistons
• • 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
  • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
  • F04B39/0027—Pulsation and noise damping means
  • F04B39/0055—Pulsation and noise damping means with a special shape of fluid passage, e.g. bends, throttles, diameter changes, pipes
• • 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
  • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
  • F04B53/06—Venting

Definitions

• the disclosure relates to reciprocating compressors. More particularly, the disclosure relates to pistons.
• One aspect of the disclosure involves a compressor comprising: a case; and at least one piston mounted for reciprocating movement, each in a respective cylinder of the case.
• the at least one piston having a peripheral surface and an upper surface, the upper surface having an outer portion and a projection extending from the upper surface.
• the at least one piston has a channel positioned to pass flow from an area above the outer portion.
• the channel is a closed channel.
• the projection has an upper end and a central recess in the upper end and the channel has an upper end at the recess.
• the channel has a lower end along a side of the projection. [0008] In one or more embodiments of any of the foregoing embodiments, the channel is one of a plurality of like channels distributed circumferentially about the at least one piston.
• the compressor comprises: a motor; a crankshaft driven by the motor; and at least one connecting rod coupling the crankshaft to the at least one piston.
• the projection has a frustoconical lateral surface.
• the channel comprises a drilled hole.
• the at least one piston comprises a plurality of identical pistons.
• the cylinder is formed in a cylinder block; a valve plate assembly is mounted to the cylinder block; and the at least one piston has a top-dead-center condition wherein the projection is at least partially within the valve plate assembly.
• the valve plate assembly has a seat forming a seating surface of a suction valve; and, in the top-dead-center condition, the projection is partially received within the seat.
• the seat forms an outer seating surface of a discharge valve;
• the valve plate assembly has an inner seat forming an inner seating surface of the discharge valve;
• the at least one piston has a recess in the projection; and, in the top-dead-center condition, the inner seat is partially received within the recess.
• a method for manufacturing the compressor comprises: drilling to form the channel. [0017] In one or more embodiments of any of the foregoing embodiments, a method for using the compressor comprises: reciprocating the piston in the cylinder, during an upward portion of the reciprocating a flow of fluid moving upward in the channel. [0018] In one or more embodiments of any of the foregoing embodiments, the flow of fluid is from a region adjacent a suction valve toward a discharge valve.
• a vapor compression system comprises the compressor.
• the vapor compression system is a refrigeration system.
• FIG. 1 is a longitudinal sectional view of a compressor.
• FIG. 1 A is an enlarged view of the forward- most two cylinders of the compressor of FIG. 1.
• FIG. IB is an enlarged view of a portion of the forward-most cylinder of the compressor of FIG. 1.
• FIG. 2 is an isolated view of a piston of the compressor of FIG. 1.
• FIG. 3 is an exploded cutaway view of a single cylinder of the compressor.
• FIG. 1 shows a compressor 20.
• the compressor has a case or housing assembly 22 which includes an inlet or suction port 24 and an outlet or discharge port 26.
• the exemplary compressor includes a motor 28 including a stator 32 and a rotor 30.
• the rotor 30 is integrated with a crankshaft 34 to drive rotation of the crankshaft about an axis 500.
• the crankshaft is supported by a plurality of bearings for rotation about the axis 500.
• the compressor is a reciprocating compressor having a plurality of pistons 40 mounted for reciprocal movement in respective associated cylinders 42 defined within a cylinder block 44 of the case.
• the exemplary cylinders are coupled to the crankshaft via wrist pins 46 carried by the pistons and connecting rods 48 coupling the wrist pins to the crankshaft.
• Each piston has a lateral or side or outer diameter (OD) surface 50 (FIG. 1A) and an upper or top surface 52.
• FIG. 1A shows a forward-most piston in a top-dead-center (TDC) position. In the TDC position, a lateral portion 54 of the upper surface 52 is approximately flush to an upper surface 60 of the cylinder block 44.
• a valve plate assembly 70 is mounted atop the surface 60 (a gasket 62 intervening) and bears valve assemblies 72 associated with the respective cylinders. As is discussed further below, the valve assemblies 72 each comprise portions forming an inlet or suction valve and portions forming a discharge or outlet valve.
• a cylinder head 74 is mounted atop the valve plate assembly (a gasket 75 intervening) and encloses a discharge plenum 76 in communication with the discharge port 26.
• FIG. 1A further shows the pistons comprising an upward projection 80 (having a lateral or side or outer diameter (OD) surface 82 and an upper or distal end 84) which, in the forward-most piston illustrated top-dead-center condition or position protrudes into the valve plate assembly 70. This helps minimize the headspace in the top-dead-center condition for improved overall flow.
• an upward projection 80 having a lateral or side or outer diameter (OD) surface 82 and an upper or distal end 84
• the exemplary valve plate assembly 70 comprises a bottom plate 90 and a top plate 92 separated by spacers.
• the spacers may include a perimeter plate 94 matching the perimeter of the valve plate assembly so as to enclose a plenum 96. Additional spacers 98 may be distributed within the plenum.
• the plenum 96 is a suction plenum in communication with the suction port 24.
• the suction plenum 96 may be in communication with the interior of the motor case via a passageway (not shown) cast in the case assembly.
• the suction valve comprises a flexible valve element 120 (FIG. IB) mounted between the valve plate assembly 70 and cylinder block 44 at the periphery of each cylinder 42.
• the valve element 120 is formed as a sheet having a lower surface 122 and an upper surface 124.
• the valve element has a central aperture defined by an inner perimeter (inner diameter (ID)) surface 126.
• ID inner diameter
• the exemplary seating surface 130 is a lower surface of a seat 132 whose upper surface forms a discharge valve seating surface as is discussed further below.
• An inner diameter (ID) surface 134 of the seat closely accommodates the OD surface 82 of the projection 80 in the top-dead-center condition.
• An OD seating surface may be formed by a portion of the underside of the bottom plate 90.
• the exemplary suction valve element is generally round but has two tabs 135 (FIG. 5) 180° apart that sit on the crankcase deck for support and two smaller tabs 136 serving as stops.
• the exemplary seat 132 comprises an upper portion mounted to the upper plate 92 (e.g., via press fit, braze, or the like) and a lower portion depending through the plenum 96 and through an associated aperture 140 in the bottom plate 90.
• reduced pressure/suction causes the valve element 120 to flex, bending in the middle (like a U) and supported by the two tabs 135 at the edge of the cylinder bore and stopped by cooperation of tabs 136 and complementary associated surfaces of recesses in the cylinder.
• the discharge valve may similarly comprise a valve element 150 (FIG. IB) which has an open condition and a closed condition.
• the exemplary valve element 150 is a spring-loaded annulus having a lower surface 152, an upper surface 154, an inner diameter (ID) perimeter surface 156, and an outer diameter (OD) perimeter surface 158.
• the exemplary seat for the valve comprises an inner diameter (ID) seat and an outer diameter (OD) seat.
• the outer diameter seat is formed by an upper seating surface 160 of the seat 132.
• the exemplary ID seat is formed by an outer diameter perimeter surface 164 of an inner seat member 166.
• the member 166 is secured centrally to a valve guide 170 which, in turn, is mounted atop the upper plate 92.
• One or more springs 180 may bias the valve element 152 into its closed condition.
• a circumferential array of metallic coil springs held in pockets 182 in the guide e.g., three to twenty such springs and pocket combinations per cylinder or eight to sixteen, with an exemplary twelve shown
• the piston projection 80 includes a central recess 200 (FIG. 1A) that receives and accommodates the discharge valve inner seat member 166 as the piston approaches top-dead-center so as to minimize headspace.
• FIG. 1 A adds channels 220 to a baseline piston configuration.
• the channels extend from lower ends 224 to upper ends 226.
• the lower ends may generally form inlet ports (inlets) and the upper ends 226 may generally form outlet ports (outlets) for flow to pass during that final stage of upward movement of the piston to the top-dead-center condition.
• the exemplary lower ends 224 are along the projection lateral surface 82; whereas, the exemplary upper ends 226 are along the recess 200.
• the exemplary channels 220 are closed channels (e.g., they have a full lateral perimeter) as distinguished from purely open channels or troughs. Accordingly, the exemplary channel 220 may be formed by drilling into the cast piston.
• An exemplary group of channels are evenly circumferentially distributed about the piston and cylinder axis 502.
• the exemplary configuration has four such channels 220 (FIG. 3). A broader range is 1-10 or 2-8.
• each hole involves a diameter of 0.5 mm and cross-sectional area of 4.9 mm 2 .
• Exemplary aggregate cross-sectional area of the channels is 19.6 mm 2 .
• Alternative individual hole cross-sectional area is at least 2.0 mm 2 or 2.0 mm 2 to 10.0 mm 2 .
• Alternative aggregate cross-sectional area is at least 5.0 mm 2 or 5.0 mm 2 to 50.0 mm 2 .
• vents 300 (FIG. IB) to the spring pockets 182.
• the baseline spring pocket is a blind bore extending upward from a lower perimeter surface portion 302 of the valve guide 170.
• the upper end of the baseline spring 180 sits against the base of the blind bore.
• the exemplary modification adds the vent 300 as a narrower passageway such as a drilled coaxial bore of smaller diameter leaving a shoulder 304 formed by a perimeter portion of the base surface of the baseline pocket.
• the vent 300 thus has a lower end 310 at the pocket 182 and an upper end 312 at an upper surface 314 of the valve guide 170.
• vent 300 One or more of several advantages may be obtained by adding the vent 300. Aspects of discharge valve responsiveness may be improved by allowing the pocket 182 to vent. For example, when the valve element 150 is driven upward from its closed position, vapor above the valve element is either driven into the pocket or squeezed laterally out through a peripheral opening 320. To the extent that vapor is driven into the pocket, this may cause back pressure in the pocket resisting upward movement of the valve element 150. To the extent that vapor is driven laterally outward, this may also involve back pressure but also may cause that vapor to compete with vapor displaced from the cylinder.
• the vent may allow vapor initially above the valve element 150 to be vented into the pocket and vapor in the pocket to be vented outward.
• the nature of spring bias may be that during some portion or all of the discharging stroke of the piston, the valve element 150 does not top out and close the lower end of the pocket 182. In this situation, a portion of the vapor being discharged from the cylinder may pass radially and axially around the OD perimeter 160 of the valve element 150 and then back inward and upward through the pocket 182 and vent 300.
• channels or other passageways may be provided so that flow may pass from the cylinder through the pockets and vents even with the valve element topped out against a stop surface.
• the illustrated channels 220 may be replaced with fully open channels along the periphery of the projection or with some form of hybrid of open channel and closed channel such as an open channel along a lower portion of the projection periphery transitioning to a closed channel penetrating into the recess 200.
• Another variation might involve replacing the array of coil springs 180 and pockets 182 with a single wave spring (e.g., in an annular space such as a downwardly-open channel). The vents could extend upward from that annular space.
• the compressor is used in a vapor compression system (e.g., refrigeration system including chillers, air conditioners, heat pumps, and the like).
• the compressor may drive refrigerant flow along the recirculating flowpath passing through one or more heat rejection heat exchangers and one or more heat absorption heat exchangers.
• the basic configuration involves a sequential flowpath passing through a heat rejection heat exchanger, an expansion device, a heat absorption heat exchanger, and returning to the compressor.
• the compressor may be made using otherwise conventional or yet-developed materials and techniques.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Compressor (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=56801873

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Citations (1)

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• 2016
  • 2016-08-19 US US15/752,058 patent/US20180238312A1/en not_active Abandoned
  • 2016-08-19 EP EP16757491.2A patent/EP3341610A1/en not_active Withdrawn
  • 2016-08-19 CN CN201680049509.2A patent/CN107923378A/zh active Pending
  • 2016-08-19 WO PCT/US2016/047782 patent/WO2017034983A1/en active Application Filing

Patent Citations (1)

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