US4873838A — Refrigerant metering in a variable flow system

Claim 1

Independent Claim 183 words

In a refrigeration system of the type having a compressor driven by a variable speed motor and a heat exchanger coil for transferring heat to a contained refrigerant, an improved expansion device and control comprising: a motor control means responsive to sensed conditions for controlling the speed of the variable speed motor by way of a command speed signal; an orifice for conducting refrigerant to the evaporator coils said orifice acting as a throttle to expand the refrigerant from a liquid to a gaseous state; a piston associated with said orifice and selectively movable between a closed position to block the flow of refrigerant through said orifice and an opened position to expose said orifice to the free flow of refrigerant therethrough; and valve control means responsive to said command speed signal for selectively causing the piston to alternate between the open and closed positions with the ratios of open to closed time being controlled to selectively regulate the resultant flow volume to a rate which is substantially proportional to said command speed when the compressor is being driven above a predetermined speed.

Claim 2

Dependent Claim 183 words

In a refrigeration system of the type having a compressor driven by a variable speed motor and a heat exchanger coil for transferring heat to a contained refrigerant, an improved expansion device and control comprising: a motor control means responsive to sensed conditions for controlling the speed of the variable speed motor by way of a command speed signal; an orifice for conducting refrigerant to the evaporator coils said orifice acting as a throttle to expand the refrigerant from a liquid to a gaseous state; a piston associated with said orifice and selectively movable between a closed position to block the flow of refrigerant through said orifice and an opened position to expose said orifice to the free flow of refrigerant therethrough; and valve control means responsive to said command speed signal for selectively causing the piston to alternate between the open and closed positions with the ratios of open to closed time being controlled to selectively regulate the resultant flow volume to a rate which is substantially proportional to said command speed when the compressor is being driven above a predetermined speed.

Claim 3

Dependent Claim 38 words

An expansion device as set forth in claim 1 and including a bypass means for bypassing a portion of the refrigerant flow around said orifice for damping the movement of said piston between its open and closed positions.

Claim 4

Dependent Claim 31 words

An expansion device as set forth in claim 1 wherein said piston is disposed at one end of said orifice and includes biasing means for biasing said piston against said orifice.

Claim 5

Dependent Claim 17 words

An expansion device as set forth in claim 1 wherein said valve control means comprises a solenoid.

Claim 6

Dependent Claim 110 words

An improved refrigerant expansion and control apparatus of the type used for metering the flow of refrigerant in a refrigeration system having a compressor driven by a variable speed motor in response to a speed command signal, comprising: a body defining an orifice for conducting the flow of refrigerant therethrough; blockage means for selectively blocking said orifice to prevent the flow of refrigerant therethrough; and modulating means for alternately applying and removing said blocking means in a controlled sequence to thereby selectively regulate the resultant refrigerant flow volume to a rate which is substantially proportional to said speed command signal when the compressor is being driven above a predetermined speed.

Claim 7

Dependent Claim 110 words

An improved refrigerant expansion and control apparatus of the type used for metering the flow of refrigerant in a refrigeration system having a compressor driven by a variable speed motor in response to a speed command signal, comprising: a body defining an orifice for conducting the flow of refrigerant therethrough; blockage means for selectively blocking said orifice to prevent the flow of refrigerant therethrough; and modulating means for alternately applying and removing said blocking means in a controlled sequence to thereby selectively regulate the resultant refrigerant flow volume to a rate which is substantially proportional to said speed command signal when the compressor is being driven above a predetermined speed.

Claim 8

Dependent Claim 41 words

A refrigerant expansion device as set forth in claim 5 wherein said body further includes a bypass channel in parallel with said orifice for metering a minimal flow of refrigerant and for damping the movement of said blocking means during modulation.

Claim 9

Dependent Claim 45 words

A refrigerant expansion device as set forth in claim 5 wherein said blockage means comprises a piston disposed at one end of said body and movable between a biased position against said body to block said orifice, and an open position away from said body.

Claim 10

Dependent Claim 25 words

A refrigerant expansion device as set forth in claim 5 wherein said modulating means comprises a solenoid with its piston connected to said blocking means.

Claim 11

Dependent Claim 113 words

In a refrigeration system having a compressor driven by a variable speed motor in response to a speed command signal, a method of controlling the volume of refrigerant flow through a refrigerant expansion device comprising the steps of: providing an orifice for the flow of refrigerant therethrough; providing a blockage means for selectively blocking said orifice to prevent the flow of refrigerant therethrough; and alternately applying and removing said blocking means, with the respective times being controlled to a desired ratio so as to thereby selectively regulate the resultant flow volume to a rate which is substantially proportional to said speed command signal when the compressor is being driven above a predetermined speed.

Claim 12

Dependent Claim 113 words

In a refrigeration system having a compressor driven by a variable speed motor in response to a speed command signal, a method of controlling the volume of refrigerant flow through a refrigerant expansion device comprising the steps of: providing an orifice for the flow of refrigerant therethrough; providing a blockage means for selectively blocking said orifice to prevent the flow of refrigerant therethrough; and alternately applying and removing said blocking means, with the respective times being controlled to a desired ratio so as to thereby selectively regulate the resultant flow volume to a rate which is substantially proportional to said speed command signal when the compressor is being driven above a predetermined speed.

Claim 13

Dependent Claim 24 words

A method as set forth in claim 1 wherein said step of alternately applying and removing said blocking means is accomplished with a solenoid.

Claim 14

Dependent Claim 39 words

A method as set forth in claim 9 and including an additional step of providing a bypass channel around said orifice to thereby bypass a portion of the refrigerant flow therearound to damp the movement of said blocking means.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-10-16	1993-04-17	1993-10-17	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-10-16	1997-04-17	1997-10-17	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-10-16	2001-04-17	2001-10-17	$7700.00	Window Closed / Lapsed

Refrigerant metering in a variable flow system

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag