At present, the electric temperature control valves produced by valve manufacturers are mainly composed of control valves, electric actuators, temperature sensors and temperature regulators. According to user needs, they can be divided into two structures: thermal supercharger and cooling supercharger. Before the heating solenoid valve works, the main spool is half open and the sensor is in its natural state. Turn on the power, all three-position five-way solenoid valve main valves are opened. Through the valve core, the medium flows into the main valve body from the direction of the arrow to heat the heat storage tank. As the temperature rises to the corresponding set value, the sensor will generate a corresponding linear signal into the integrated actuator, drive the valve stem, and the valve core will be displaced accordingly, closing the main valve core and stopping heating.
When the temperature is lower than the set value, the sensing element inputs a linear signal to the integrated actuator to drive the valve core to gradually open, so that the medium flows into the heat storage chamber according to the parabolic characteristic, and is heated to the set value. Therefore, the controlled medium of the two-position five-way solenoid valve is always controlled within the set temperature range, so as to achieve the purpose of temperature control. Note: Usually refers to heating type and cooling type. The valve can be realized only by replacing the spool structure.
Before installation, check whether the parts of the whole machine are damaged or loose, the pipes should be cleaned, and the flow direction of the medium should be consistent with the direction of the arrow on the valve body.
Try to install it in a place where vibration and impact are small. When the weight of the valve is large, there should be a fixed support frame. The setting location should be considered convenient for operation and easy for maintenance.
(3) In order to make the automatic control system fail or continue to work when the valve is overhauled, the direct-acting solenoid valve should be equipped with a bypass type manual valve. When servicing and using manual valves, close the shut-off valves before and after the valve first.
I am immersed in the temperature regulating medium and installed on a horizontal or inclined upper part.
The bending radius of the capillary tube should not be less than 75 mm, and it should not be folded or twisted when placed in a natural state.
(6) In order to facilitate on-site monitoring and temperature setting, a pressure gauge and a temperature gauge at the insertion position of the temperature bulb should be installed in front of the valve, and the system can be operated and installed on site.
Common problems on the regulator site include: closed undead, open unopened, large hysteresis, leakage, vibration, oscillation, etc. The treatment methods are as follows:
(1) Valve core failure:
The solution to the air-close valve is to increase the air source pressure or loosen the spring preload (that is, reduce the outdoor starting pressure of the air). The solution to this problem is to increase the preload of the spring while increasing the starting pressure.
(2) Slow or invalid putting action:
Check whether the diaphragm, rolling film, and gasket are aging, cracked and leaked.
(3) Large return difference:
Whether the push rod is bent, whether the packing gland is too tight, especially the graphite packing, and whether the valve core guide is damaged. The solution is to replace the valve stem, replace the packing, increase the guide gap, and replace the powerful actuator.
(4) The full stroke of the valve is insufficient:
Release the valve stem connecting nut to rotate or extend the valve stem. If the total deviation of the stroke exceeds the allowable value, close the nut again.
(5) Poor valve opening:
First check on the site whether the flow direction is reversed, or the valve selection is too large, the solution is to change the flow direction to open the installation and reduce the spool size.
(6) The valve action is unstable:
The positioner is faulty, the output tube is leaking, the driver stiffness is too small, and the fluid pressure changes too small, resulting in insufficient thrust. The method is to repair the positioner and pipelines and use high-stiffness actuators.