# US 12,000,399 B2 · Volume ratio control system for a compressor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,000,399 B2 - Document ID: US12000399B2 - Status: Granted - Kind: B2 - Application number: 17/791,183 - Filed: 2021-01-07 - Published: 2023-02-02 - Granted: 2024-06-04 - Earliest claimed: 2020-01-07 - Assignees: Tyco Fire & Security GmbH - Applicants: Johnson Controls Tyco IP Holdings LLP - Inventors: Paul Nemit, Jr.; Angela Marie Comstock; Franklin Aaron Montejo; Colin Campbell - Web page: https://patentgrep.com/patent/US12000399B2 ## CPC - F04C 18/16: with helical teeth, e.g. chevron-shaped, screw type {(for non-parallel axes of movement F04C18/48)} - F04C 28/12: using sliding valves - F25B 41/39: Dispositions with two or more expansion means arranged in series, i.e. multi-stage expansion, on a refrigerant line leading to the same evaporator - F25B 2339/047: Water-cooled condensers - F25B 2400/13: Economisers - F25B 2600/0253: with variable speed - F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS ## Abstract A volume ratio control system for a compressor includes a chamber formed within a housing of the compressor, where the chamber is in fluid communication with a high pressure side of the compressor, a piston disposed within the chamber, where the piston includes a cavity in fluid communication with a low pressure side of the compressor, and a biasing device disposed within the chamber and configured to enable movement of the piston in response to a pressure differential between the low pressure side of the compressor and the high pressure side of the compressor falling below a threshold value. ## Claims ### Claim 1 A volume ratio control system for a compressor, comprising: a chamber formed within a housing of the compressor, wherein a portion of the chamber is in fluid communication with a high pressure side of the compressor; a piston disposed within the chamber, wherein the piston comprises a cavity in fluid communication with a low pressure side of the compressor, wherein the portion of the chamber and the cavity are fluidly separate from one another; and a biasing device disposed within the cavity and configured to enable movement of the piston in response to a pressure differential between the low pressure side of the compressor and the high pressure side of the compressor falling below a threshold value wherein the threshold value is a variable threshold value. ### Claim 2 (depends on 1) The volume ratio control system of claim 1, wherein the low pressure side is a suction side of the compressor, and the high pressure side is a discharge side of the compressor. ### Claim 3 (depends on 1) The volume ratio control system of claim 1, comprising a rod extending into the chamber and extending into the cavity, wherein the rod is configured to form a seal between the portion of the chamber and the cavity of the piston. ### Claim 4 (depends on 3) The volume ratio control system of claim 3, wherein a position of the rod within the chamber is fixed. ### Claim 5 (depends on 4) The volume ratio control system of claim 4, wherein the portion is a first portion, and the rod extends through an opening between the first portion of the chamber fluidly coupled to the high pressure side of the compressor and a second portion of the chamber fluidly coupled to the low pressure side of the compressor. ### Claim 6 (depends on 3) The volume ratio control system of claim 3, wherein the rod comprises a passage fluidly coupling the low pressure side of the compressor and the cavity of the piston. ### Claim 7 (depends on 3) The volume ratio control system of claim 3, wherein the biasing device is disposed within the cavity radially between the rod and an interior surface of the piston. ### Claim 8 (depends on 1) The volume ratio control system of claim 1, wherein the piston is an annular piston. ### Claim 9 (depends on 1) The volume ratio control system of claim 1, wherein the piston comprises a first segment having a first radial thickness and a second segment having a second radial thickness, wherein the first segment is positioned proximate to a compressor discharge line formed within the housing, and wherein the first radial thickness is greater than the second radial thickness. ### Claim 10 (depends on 1) The volume ratio control system of claim 1, wherein the biasing device comprises a spring. ### Claim 11 (depends on 1) The volume ratio control system of claim 1, wherein the piston is configured to move in a first direction along an axis defining a length of the chamber in response to the pressure differential between the low pressure side of the compressor and the high pressure side of the compressor exceeding the threshold value, and wherein the biasing device is configured to enable movement of the piston in a second direction, opposite the first direction, in response to the pressure differential falling below the threshold value. ### Claim 12 (depends on 11) The volume ratio control system of claim 11, wherein the threshold value is a variable threshold value that varies based on a position of the piston along the axis defining the length of the chamber, a parameter of the biasing device, or both. ### Claim 13 A heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system, comprising: a compressor configured to circulate a refrigerant through a refrigerant circuit; and a volume ratio control system configured to adjust a volume ratio of the compressor, wherein the volume ratio control system comprises: a chamber formed in a housing of the compressor, wherein a portion of the chamber is in fluid communication with a high pressure side of the compressor; a piston disposed within the chamber, wherein the piston comprises a cavity in fluid communication with a low pressure side of the compressor, and wherein the portion of the chamber and the cavity are fluidly separate from one another; and a biasing device disposed within the cavity, wherein the biasing device is configured to enable movement of the piston in response to a pressure differential between the low pressure side of the compressor and the high pressure side of the compressor falling below a threshold value wherein the threshold value is a variable threshold value. ### Claim 14 (depends on 13) The HVAC&R system of claim 13, wherein the volume ratio control system is configured to passively adjust the volume ratio of the compressor based on the pressure differential between the low pressure side of the compressor and the high pressure side of the compressor and based on the biasing device. ### Claim 15 (depends on 13) The HVAC&R system of claim 13, wherein the housing comprises one or more openings fluidly coupling the chamber to a compression chamber of the compressor. ### Claim 16 (depends on 15) The HVAC&R system of claim 15, wherein the biasing device is configured to direct movement of the piston in a first direction to expose at least an opening of the one or more openings in response to the pressure differential between the low pressure side of the compressor and the high pressure side of the compressor falling below the threshold value. ### Claim 17 (depends on 16) The HVAC&R system of claim 16, wherein piston is configured to move in a second direction, opposite the first direction in response to the pressure differential between the low pressure side of the compressor and the high pressure side of the compressor exceeding the threshold value. ### Claim 18 A volume ratio control system for a compressor, comprising: a chamber formed within a housing of the compressor, wherein the chamber comprises a first portion in fluid communication with a high pressure side of the compressor and a second portion in fluid communication with a low pressure side of the compressor; a rod extending through an opening of the housing separating the first portion and the second portion of the chamber, wherein the rod is fixed within the chamber with respect to an axis defining a length of the chamber; a piston disposed within the first portion of the chamber, wherein the piston comprises a cavity in fluid communication with the second portion of the chamber, and wherein the rod is at least partially disposed within the cavity of the piston; and a biasing device disposed within the cavity between the rod and an interior surface of the piston, wherein the biasing device is configured to enable movement of the piston within the chamber in response to a pressure differential between the low pressure side of the compressor and the high pressure side of the compressor falling below a threshold value wherein the threshold value is a variable threshold value. ### Claim 19 (depends on 18) The volume ratio control system of claim 18, wherein the rod is configured to form a seal between the first portion and the second portion of the chamber. ### Claim 20 (depends on 18) The volume ratio control system of claim 18, wherein piston is configured to move in a first direction along the axis defining the length of the chamber in response to the pressure differential between the low pressure side of the compressor and the high pressure side of the compressor exceeding the threshold value, and wherein the biasing device is configured to enable movement of the piston in a second direction, opposite the first direction, in response to the pressure differential falling below the threshold value. ### Claim 21 (depends on 18) The volume ratio control system of claim 18, wherein the threshold value is a variable threshold value that varies based on a position of the piston along the axis defining the length of the chamber, a parameter of the biasing device, or both.