Capacity Control Valve Using Differential Pressure for Start-Up Balance
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Solution Overview
Problem
Existing capacity control valves face inefficiencies in responsiveness during start-up and operation due to inadequate discharge of liquefied fluid from the control chamber, leading to differential pressure imbalances and reduced operation efficiency.
Innovation Solution
The capacity control valve incorporates a differential pressure valve that communicates the Pc port with the Ps port, allowing liquefied fluid to be discharged quickly and maintaining equal pressures during start-up, and utilizes a pressure-sensitive valve and a differential pressure valve element to ensure smooth operation and maximum capacity state maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the capacity control valve uses only the pressure-sensitive valve to discharge liquefied fluid during start-up, then the valve structure is simple, but the discharge speed is insufficient and responsiveness is poor
Solution Approach 1:
The discharge function is segmented into two parallel paths: a pressure-sensitive valve path and a differential pressure valve path. The pressure-sensitive valve handles normal pressure regulation, while the differential pressure valve specifically handles rapid discharge of liquefied fluid during start-up. This segmentation allows each valve to be optimized for its specific function, achieving fast discharge without excessive structural complexity.
Solution Approach 2:
The differential pressure valve acts as an intermediary mechanism that activates only when needed (during start-up with liquefied fluid). It provides an additional discharge path that works in conjunction with the pressure-sensitive valve, enabling rapid fluid discharge without requiring the pressure-sensitive valve to be oversized or overly complex.
2Productivity
If the capacity control valve maintains maximum capacity state after start-up, then operation efficiency is improved, but the pressure-sensitive valve cannot open when suction pressure is low, causing differential pressure imbalance
Solution Approach 1:
The differential pressure valve provides feedback control for pressure balance. When the suction pressure drops after start-up, the differential pressure valve automatically adjusts to maintain the pressure difference needed for the pressure-sensitive valve to remain closed, ensuring the system maintains maximum capacity state while preserving pressure balance stability.
Solution Approach 2:
The differential pressure valve automatically activates when needed without external control. During start-up, it opens to discharge liquefied fluid; during normal operation, it self-adjusts to maintain pressure balance when the pressure-sensitive valve would otherwise fail to open due to low suction pressure, ensuring continuous maximum capacity operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances start-up responsiveness and maintains the maximum capacity state, improving operation efficiency by ensuring equal control and suction pressures, thus stabilizing the piston stroke and overall system performance.
Implementation Method 1
a pressure-sensitive element 160 which is disposed inside the third valve chamber 140 and applies an urging force to the main valve element 151 in a valve opening direction of the main valve in response to an ambient fluid pressure
Implementation Method 2
a main valve element 151 which integrally includes a first valve portion 151a coming into contact with and separating from the first valve seat 110a in the first valve chamber 120 so as to open and close a communication between the discharge chamber and the control chamber and a second valve portion 151b coming into contact with and separating from the second valve seat 182a in the second valve chamber 130 so as to open and close a communication between the control chamber and the suction chamber and performs an opening and closing operation in the mutually opposite directions by the reciprocating movement, an intermediate communication path 155 which communicates the second valve chamber 130 with the third valve chamber 140, a pressure-sensitive element 160 which is disposed inside the third valve chamber 140 and applies an urging force to the main valve element 151 in a valve opening direction of the main valve in response to an ambient fluid pressure
Implementation Method 3
When the variable displacement compressor is stopped and is left in a stop state for a long time, the suction pressure Ps, the discharge pressure Pd, and the control pressure Pc of the variable displacement compressor are equalized, the control pressure Pc and the suction pressure Ps are much higher than the control pressure Pc and the suction pressure Ps in the continuous driving state, and a part of the fluid inside the control chamber is liquefied
Data Source
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AI summary
There is provided a capacity control valve having good responsiveness during start-up and good operation efficiency. A capacity control valve V includes: a valve housing 10, 16 provided with a Pc port 14, a Ps port 15 and a Pd port 12; a main valve element 51 which includes a main valve portion 51a coming into contact with and separating from a main valve seat 10a and opens and closes a communication between the Pd port 12 and the Pc port 14 by a drive force of a solenoid 80; an intermediate communication path 55 which is able to communicate the Pc port 14 with the Ps port 12; and a pressure-sensitive valve 53 capable of opening and closings the intermediate communication path 55 by an ambient pressure, in which the valve housing 10, 16 have a differential pressure valve 90 housed therein, the differential pressure valve 90 including a differential pressure valve element 91 and being capable of opening and closing a communication between the Pc port 14 and the Ps port 15 by the differential pressure valve element 91 moved by an operation force of an operation member 93 operated by a discharge pressure Pd from the Pd port 12.