US 11,892,210 B2
Valve and capillary tube system for refrigeration systems
Timothy D. Swofford, Midlothian, VA (US); and Roy Bates, Chesterfield, VA (US)
Assigned to Hill Phoenix, Inc., Conyers, GA (US)
Filed by Hill Phoenix, Inc., Conyers, GA (US)
Filed on Jun. 7, 2021, as Appl. No. 17/341,021.
Application 17/341,021 is a continuation of application No. 15/642,856, filed on Jul. 6, 2017, granted, now 11,029,066.
Claims priority of provisional application 62/360,791, filed on Jul. 11, 2016.
Prior Publication US 2021/0364200 A1, Nov. 25, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. F25B 41/37 (2021.01); F25B 49/02 (2006.01); F25B 41/39 (2021.01); F25B 41/385 (2021.01); F25B 41/34 (2021.01)
CPC F25B 41/37 (2021.01) [F25B 41/34 (2021.01); F25B 41/385 (2021.01); F25B 41/39 (2021.01); F25B 49/02 (2013.01); F25B 2341/062 (2013.01); F25B 2400/0411 (2013.01); F25B 2600/21 (2013.01); F25B 2600/2513 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A refrigeration system, comprising:
an evaporator;
a condenser;
a compressor configured to circulate a refrigerant between the evaporator and the condenser;
a capillary tube positioned downstream from the condenser and configured to receive refrigerant exiting from the condenser, the capillary tube configured to cause a fixed decrease in a measurable thermodynamic property of the refrigerant as a result of a geometry of the capillary tube;
an expansion valve positioned in series with the capillary tube and configured to receive the refrigerant from the capillary tube and provide the refrigerant to the evaporator, the expansion valve adjustable to control a flow rate of the refrigerant through the capillary tube and cause a variable decrease in the measurable thermodynamic property of the refrigerant based at least in part on a refrigeration load, the refrigerant exiting from the condenser passes through the capillary tube before being supplied to the expansion valve;
a bypass line arranged in parallel with the expansion valve and configured to allow a first portion of the refrigerant to bypass the expansion valve while allowing a second portion of the refrigerant to pass through the expansion valve, the bypass line comprising a bleeder system configured to bypass the first portion of the refrigerant in the bypass line at an order of magnitude less than the second portion of the refrigerant passed to the expansion valve;
a sensor positioned downstream of the capillary tube and configured to measure a temperature of the refrigerant and generate a signal corresponding to the measured temperature of the refrigerant; and
a controller in communication with the sensor and configured to:
determine an amount of superheat in the refrigerant at an outlet of the evaporator based on the measured temperature;
compare the amount of superheat to a superheat setpoint; and
drive the amount of superheat to the superheat setpoint by adjusting a decrease in the measurable thermodynamic property of the of the refrigerant by modulating the expansion valve, the decrease in the measurable thermodynamic property of the refrigerant being a sum of the fixed decrease in the measurable thermodynamic property of the refrigerant caused by the capillary tube and the variable decrease in the measurable thermodynamic property of the refrigerant caused by the expansion valve.
 
9. A refrigeration system, comprising:
an evaporator;
a condenser;
a compressor configured to circulate a refrigerant between the evaporator and the condenser, a charge of the refrigerant in the refrigeration system different than a critical charge of the refrigerant;
a capillary tube positioned downstream from the condenser and configured to receive refrigerant exiting from the condenser, the capillary tube being configured to cause a fixed decrease in a measurable thermodynamic property of the refrigerant as a result of a geometry of the capillary tube;
an expansion valve positioned in series with the capillary tube and configured to receive the refrigerant from the capillary tube and provide the refrigerant to the evaporator, the expansion valve adjustable to control a flow rate of the refrigerant through the capillary tube and cause a variable decrease in the measurable thermodynamic property of the refrigerant to accommodate a refrigeration load, the refrigerant exiting from the condenser passing through the capillary tube before being supplied to the expansion valve;
a sensor positioned downstream of the capillary tube and configured to measure a temperature of the refrigerant and generate a signal corresponding to the measured temperature of the refrigerant; and
a controller in communication with the sensor and configured to:
determine an amount of superheat in the refrigerant at an outlet of the evaporator based on the measured temperature;
compare the amount of superheat to a superheat setpoint; and
drive the amount of superheat to the superheat setpoint by adjusting a decrease in the measurable thermodynamic property of the of the refrigerant by modulating the expansion valve, the decrease in the measurable thermodynamic property of the refrigerant being a sum of the fixed decrease in the measurable thermodynamic property of the refrigerant caused by the capillary tube and the variable decrease in the measurable thermodynamic property of the refrigerant caused by the expansion valve.
 
15. A valve assembly for a refrigeration system, the valve assembly comprising:
a capillary tube configured to receive all refrigerant exiting from a condenser of the refrigeration system and cause a fixed decrease in a measurable thermodynamic property of the refrigerant as a result of a geometry of the capillary tube;
an expansion valve positioned downstream of the capillary tube and configured to receive the refrigerant from the capillary tube and provide the refrigerant to an evaporator of the refrigeration system, the expansion valve adjustable to cause a variable decrease in the measureable thermodynamic property of the refrigerant to accommodate varying refrigeration loads, the expansion valve positioned within the valve assembly such that refrigerant passing through the expansion valve first passes through the capillary tube;
a bypass line arranged in parallel with the expansion valve and configured to allow a portion of the refrigerant to bypass the expansion valve while requiring a remaining amount of the refrigerant to pass through the expansion valve, the bypass line comprising a bleeder system configured to bypass the portion of the refrigerant in the bypass line at an order of magnitude less than the remaining amount of the refrigerant to pass through the expansion valve;
a sensor positioned downstream of the evaporator and configured to measure a temperature of the refrigerant upon exiting the evaporator; and
a controller in communication with the sensor and configured to:
determine an amount of superheat in the refrigerant at an outlet of the evaporator based on the measured temperature;
compare the amount of superheat to a superheat setpoint; and
drive the amount of superheat to the superheat setpoint by adjusting a decrease in the measurable thermodynamic property of the of the refrigerant by modulating the expansion valve, the decrease in the measurable thermodynamic property of the refrigerant being a sum of the fixed decrease in the measurable thermodynamic property of the refrigerant caused by the capillary tube and the variable decrease in the measurable thermodynamic property of the refrigerant caused by the expansion valve.