Factors affecting the stable operation of gas pressure reducing valves
1. Working principle of domestic pressure reducing valve
The opening of the pilot valve is rotated clockwise by the adjusting bolt at the top, so that the elastic force generated by the spring shrinkage causes the diaphragm of the pilot valve to sag downward, and the force acting on the connecting rod of the valve is shifted downward to open the guide. valve. When the pilot valve is opened, the steam in the upstream inlet pipe section a passes through the α channel (supply steam regulating passage), enters the pilot valve annular steam chamber through the pilot valve, and is directly sent to the lower piston cylinder upper chamber by the β channel. Under the continuous supply of a cavity steam, the pressure continues to rise, pushing the piston down to open the main valve, at which time the steam source continuously flows from the cavity a to the cavity b. When the downstream outlet pipe section b cavity load is satisfied, the excess steam causes the pressure in the b cavity to continuously increase. The increasing pressure is fed back to the lower chamber of the pilot diaphragm through the gamma channel (pressure sensing channel), causing the diaphragm of the pilot valve to protrude upward, overcoming the pressure of the upper adjusting spring, and the pilot valve is closed or closed. Thus, the source of steam from the upstream alpha channel is turned off or turned off. When the pressure in the upper chamber of the piston cylinder drops, the main valve is closed or closed under the action of the lower return spring. At this time, the pressure in the b chamber begins to decrease, so that the pressure regulation is repeated.
2. Working principle of imported pressure reducing valve
When the pilot valve is opened, the steam in the upstream pipe section a quickly enters the inner filter cover, and reaches the a channel (supply steam regulating passage) through the pilot valve. When the a channel is filled with steam, it is directly sent to the lower diaphragm of the main valve diaphragm, and at the same time, part of The steam is split into the b chamber through the b channel (pressure control channel). The lower cavity of the main valve diaphragm is continuously supplied under the a-channel steam, and the main cutting diaphragm is pressed upwards, and the generated thrust pushes the main valve rod upward to open the main valve, and the same steam continuously flows from the a cavity to the b cavity. . When the load of the downstream outlet pipe section is satisfied, the excess steam also increases the pressure in the b-cavity, and the increasing pressure is transmitted to the lower steam chamber of the pilot valve diaphragm through the c-channel (pressure sensing channel). When the diaphragm of the pilot valve protrudes upward, against the pressure of the upper adjusting spring, the pilot valve is closed or closed to reduce and cut off the steam from the cavity a. When the pressure in the lower chamber of the main valve diaphragm is gradually reduced, the upper main valve spring acts to lower the main valve spool, and the main valve is closed or closed (excess steam is simultaneously released into the b chamber through the b channel, the main valve is Quickly shut down), so that the pressure of the b cavity is continuously decreasing, so as to achieve adjustment. (The principle of opening the pilot valve, the same as the domestic valve)
3. Analysis of the mechanism of condensate water damage regulation
When the downstream pressure rises (in the b cavity) when pressure is required to be lowered. Under normal conditions, the super-high pressure of the b-cavity is transmitted to the pilot valve through the pressure-sensing passage (γ), so that the pilot valve is closed or closed, thereby closing and cutting off the steam source from the a-cavity. When the condensed water invades into the cylinder and the annular steam chamber, due to the incompressible nature of the water, at this time, the main valve return spring completely loses its function, the piston cannot move up, the main valve cannot be closed, and the steam at the inlet (a cavity) is still continuously flowing. , through the main valve in the normally open state into the b cavity. Make the pressure too high and get out of control. When the system condensate fills the a and b channels and the main diaphragm lower chamber. Under the thrust from a cavity steam, the main valve diaphragm is in an upwardly bulged state. Similarly, the water is incompressible, so that the upper return spring cannot be returned to the seat, and the main valve is also in the normally open state, and the stable adjustment function is destroyed.
Although the pressure reducing valve is a proportional regulating valve, when the condensed water is filled with these core working parts in the valve, the proportional adjustment property is completely changed. The key problem is the action of the frictional resistance of the moving parts and the sequence of actions. The time difference determines the hysteresis of the main valve motion. (The pilot valve is first, the main valve is trailing behind.) After receiving the overpressure message from γ and c channels, first, close or close the pilot valve. In this way, the retreat of the condensed water in the valve is cut off, and it is obvious that the piston and the main valve diaphragm cannot move.
According to the above, it can be known that the system condensed water is not beneficial to the heating project. Therefore, the system condensate is the most basic reason for destroying the regulation function of the steam pressure reducing valve.
(Source: Hebei Zhenxing Gas Pressure Regulator Co., Ltd. gas pressure regulator)
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
Solar Fan,Solar Powered Fan,Solar Exhaust Fan,Solar Powered Outdoor Fan
Jiamei Energy(hongkong) Limited , https://www.jiameilight.com