【Q&A Question 001】2017.01.01
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This post was last edited by 955559 on 2017-7-21 at 13:29. [Q&A Question 001] January 1, 2017: Working principle of the reciprocating machine unloader. The reference answers will be visible after responding; scoring is granted by identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) The unloader unloads by keeping the intake valve open at all times. 2017 Q&A Summary Thread (updates have started) http://bbs.hcbbs.com/thread-1657793-1-1.html 2017 Daily Question Summary Thread (updates have started) http://bbs.hcbbs.com/thread-1657794-1-1.html 2016 Q&A Summary Thread (updates completed) http://bbs.hcbbs.com/thread-1597792-1-1.html Xinchang Cup – 2016 HaiChuan Top 10 Selection – Please recommend candidates http://bbs.hcbbs.com/thread-1654112-1-1.html Third Round of HaiChuan Outstanding Management Members Selection http://bbs.hcbbs.com/thread-1655902-1-1.html (Source: HaiChuan Chemical Forum)
The instrument air control fork forces the intake valve to lift, causing the valve to lose its one-way flow function.
Let’s learn about the working principle as found online: ① When unloading is required, power air with a pressure of around 0.4 MPa (instrument air) is introduced above the power piston. Under the action of this power air, the power piston moves downward, compressing the spring located below it. As the power piston moves downward, the shaft connected to it also moves downward, which in turn pushes the fork rod downward. The fork rod then pushes the intake valve element, compressing its spring and causing the intake element to move away from the valve seat, thereby creating a gas passage. This eliminates the one-way flow property of the intake valve, achieving the purpose of unloading； ②When load is applied, the power air on the power piston is released; under the force of the spring below it, the power piston, shaft, and fork move upward, allowing the suction valve element to return to its normal operating state.
Working principle: ① When unloading is required, power air (instrument air) at approximately 0.4 MPa is supplied above the power piston. Under the action of this power air, the power piston moves downward, compressing the spring installed below it. As the power piston moves downward, the shaft connected to it also moves downward, which in turn pushes the fork rod downward. The fork rod then pushes the intake valve element, compressing its spring and causing the intake element to move away from the valve seat, thereby creating a gas passage and rendering the intake valve unable to function as a one-way valve, thus achieving the purpose of unloading； ②When load is applied, the power air on the power piston is released; under the force of the spring below it, the power piston, shaft, and fork move upward, allowing the suction valve element to return to its normal operating state. Working principle: ① When unloading is required, power air (instrument air) at approximately 0.4 MPa is supplied above the power piston. Under the action of this power air, the power piston moves downward, compressing the spring installed below it. As the power piston moves downward, the shaft connected to it also moves downward, which in turn pushes the fork rod downward. The fork rod then pushes the intake valve element, compressing its spring and causing the intake element to move away from the valve seat, thereby creating a gas passage and rendering the intake valve unable to function as a one-way valve, thus achieving the purpose of unloading ； ②When load is applied, the power air on the power piston is released; under the force of the spring below it, the power piston, shaft, and fork move upward, allowing the suction valve element to return to its normal operating state.
Valve responsible for opening and closing the intake passage
The principle of the unloader is to control the delayed closure of the air valve flap in order to adjust the air intake volume. When the valve disc is about to close, the unloader creates the necessary conditions for a delayed closure, allowing the amount of air that has been drawn in to return to the inlet and thus regulating the volume of air, thereby achieving the effect of unloading!
A unloader uses a force to push open the air valve; this pressure can be provided by nitrogen, instrument air, or solenoid valves, and it is used to load or unload the compressor. For example, in the case of wind loading, at zero load, pressure acts on the unloader, which causes the air valve to open fully; as a result, when the compressor compresses gas, the gas is discharged through the intake valve, and the load is zero.
A unloader uses a force to push open the air valve; this pressure can be supplied by nitrogen or instrument air, and it is used to load or unload the compressor. For example, in the case of wind loading, at zero load, pressure acts on the unloader, which causes the air valve to open fully; as a result, when the compressor compresses gas, the gas is discharged through the intake valve, and the load is zero.
The unloader pushes the air valves open or activates them; at a value of 0, all the air valves are pushed open by the unloader and no work is done. At 50, the air valves on the shaft side perform work, and at 100, all the air valves perform work!
When the unloader is in operation, the suction valve can only be in an fully open or fully closed state; it is based on this principle that the air volume is regulated, and adjustments can be made sequentially at 0%, 25%, 50%, 75%, and 100%.