Pressure reducing valves are mechanisms that are designed to maintain low pressure in the fluid outlet. Most often, such tools are used in hydraulic drives in which several devices are fed from one pump at once. In this case, pressure reducing valves normalize the pressure under which fluid is supplied to all consumers, that is, the system does not have an excessively high or, conversely, low pressure. This device can significantly reduce the risk of damage to the main supply lines of the working fluid associated with excessive pressure inside the system.
This mechanism consists of the following parts:
- calibrated spring;
- ball;
- spool;
- damper;
- high pressure supply;
- internal cavities in the housing for controlling the spool.
Pressure reducing valve: photo and principle of operation
The fluid, which is supplied from the main line, enters the internal control cavity and, through a special annular gap between the spool and the housing, is fed into the hole associated with the entire system of the mechanism.
In the case when the pressure in the line rises, the ball inside the mechanism also rises, and the pressure in the control cavity decreases to normal. This hole is replenished with working fluid from other cavities, as well as from the hole of a small cross section of the damper. The spool can regulate the pressure in only two lines, blocking the channel for supplying the working fluid from the main system. Thus, this part increases the resistance of the fluid passage, as a result of which the pressure in the cavity increases, which is determined by the force of the calibrated spring.
When the pressure in the system decreases, the spool moves under the influence of a spring, thereby increasing the annular gap between the two cavities. Pressure reducing valves in this case change the pressure of the fluid supply in one of the holes.
Based on this, we see that at the outlet the pressure level remains unchanged and is maintained by the device at the optimum level, regardless of the pressure of the hydraulic line and the flow rate of the working fluid.
What to do if the mechanism does not support normal water supply?
It sometimes happens that pressure reducing valves are not able to provide all users with normal pressure. In this case, it should be adjusted. Each device, including the VAZ 2109 pressure reducing valve, has a special adjustment screw on the body, which affects the closing and opening of the spool in the system. With proper adjustment, you can achieve ideal values for the flow of working fluid.
Price
At the moment, the average cost of this device is 5-5.5 thousand rubles. The cheapest pressure reducing valves can be purchased for 1200-1300 rubles. The most expensive options cost about ten thousand.
Conclusion
So, we learned what the pressure reducing valve consists of, and found out how the position of the spool and ball affects the pressure in the internal cavities of the mechanism.