Add solenoid valves to the circulating water pipe
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Dear sea friends, we currently use manual valves to control the circulation of water. We plan to use the temperature of the equipment to regulate the on/off of the circulating water. Therefore, solenoid valves need to be installed on the water pipes to be controlled by temperature. The field device temperature sensor only has display and alarm functions. Ours doesn’t have a central control unit nor a PLC. Question: How is the solenoid valve for water pipes connected to the temperature at the site, in order to control the opening and closing of the water flow? What type of electricity is used by the solenoid valve? 24V DC or 220V AC?
You have reported it to the police, indicating that there are digital input signals; that’s sufficient. Just connect the control signal for the solenoid valve to this alarm point! ! Both 24V and 220V solenoid valves are available!
If your requirement is to trigger an alarm and then use that to control the solenoid valve, you can do as mentioned above. But if you need to obtain an intermediate temperature value in order to control the solenoid valve, it’s better to use a PLC; controlling analog values seems difficult to achieve solely with hardware.
Isn’t the pipe too small? Electromagnetic valves may not be suitable for circulating water.
There are no solenoid valves that are large enough; you should use a on/off valve, or if there is no air supply, an electric valve will work as well. If you don’t want to use a PLC, you can also use a secondary meter as a controller
To control the temperature, a control valve should be installed, along with a conventional gauge: a regulator. The on-site temperature signal is fed into the regulator, and the regulator’s output signal is sent to the valve.
Select a digital controller with passive contacts, set the temperature to be controlled, and use the hysteresis ratio to control the on/off operation of the solenoid valve. For pipe-type solenoid valves (with relatively small diameters), 24VDC is the best choice, as it is a safe voltage. However, if 24V DC is not available, 220V AC can be used; the choice depends on one’s own requirements. By connecting the power supply to the passive contacts of the digital regulator and then linking it to the solenoid valve, the owner’s idea can be realized. PS: There are many types of solenoid valves; I’m not sure whether the poster is referring to those used in pipelines or those incorporated in shut-off valves. But the approach is the same.
Personally, I think that if the goal is to control the temperature of a device, a control valve is the most suitable choice. The control scheme is basically the same as the one described above, with the only difference being that the output contact of the regulator is 4~20mA
Use a solenoid valve with a DC24V voltage – it’s safe! To achieve control, just buy a temperature control instrument – it’s cheap and simple.