Electric thermostat simple principle and problem solving method

Electric thermostatic valve features only the most common 220V power supply, the use of the media itself is the media energy, direct steam, hot water, hot oil and gas and other media to automatically adjust the temperature and control, can also be used to prevent overheating or heat Exchange occasions, electric temperature control valve structure is simple, easy to operate, the selection of a wide range of temperature control, fast response time, reliable sealing performance, and can be freely adjusted in operation, electric temperature control valve is widely used in chemical, petroleum, food, Textile, hotels and restaurants and other departments of the hot water supply. Installation matters: (1) Before installation, check the machine parts for defects and loose, the pipeline should be cleaned, the media flow direction should be consistent with the arrow on the valve body. (2) try to install the vibration persuade and impact small place, the valve weight since the larger, there should be a fixed support frame. Installation site should be considered easy to operate, but also conducive to maintenance. (3) In order to make the automatic control system failure or overhauling the valve can still run continuously, should be set bypass manual valve. Maintenance and use of manual valve, the valve should be closed before and after the closing valve. (4) Warm me all immersed in the medium to be adjusted, and in a horizontal or inclined installation. (5) capillary bend radius of not less than 75mm, placed in a natural state, no folding or distortion. (6) In order to facilitate on-site monitoring and temperature setting, a pressure gauge should be set in front of the valve and a thermometer inserted in the warm pack to install the system on site. Working principle Electric temperature control valve by the control valve, electric actuator, temperature sensor and temperature regulator and other components, according to user needs, respectively, heating and cooling two structures. The structure and principle of the heating type control valve: Before working, the main valve core is in the half-open position, and the sensor is in a natural state. Connect the power, the main spool fully open. The medium flows into the main valve body in the direction of the arrow, and the heat storage tank is heated by the valve core. When the temperature rises to the corresponding set value, the sensor generates a corresponding linear signal input to the integrated actuator, which then drives the valve stem, the valve spool displaces and closes the main valve plug to stop heating. When the temperature is lower than the set value, the sensor generates a linear signal input to the integrated actuator, which drives the valve to be involute, allowing the medium to flow into the thermal storage tank according to the parabolic characteristic and heating up to the set value. This controlled media is always in the set temperature range is controlled, so as to achieve the purpose of temperature control. Note: often say that the heating type, cooling type. In this valve as long as the spool structure can be replaced. Valve on-site common problem is not dead, can not open, hysteresis, leakage, vibration, oscillation, etc., the treatment methods are as follows: (1) valve core is immortal: the gas valve solution is to increase air supply Pressure or loose spring preload (ie to reduce the pressure outside the starting point of the gas chamber). The solution to open the valve is to increase the spring preload, while increasing the source pressure. (2) push rod slow or not action: test diaphragm, rolling diaphragm, gasket aging, rupture caused by leakage. (3) large backlash: pushrod is bent, the packing gland is pressed too tight, especially graphite packing, valve-oriented for injury. The solution is to replace the valve stem, for packing, increase the guide gap, for strength enforcement agencies. (4) The valve full stroke is not enough: Loosen the stem connecting nut, the stem outward rotation or inward stretch. So that the entire stroke deviation exceeds the allowable value and then tighten the nut. (5) valve small opening stability is poor: the scene first check whether the flow of anti-installed, or valve too large, the solution is to open the flow of change, reduce spool size. (6) valve instability: locator failure, the output pipeline leakage, the actuator stiffness is too small fluid pressure changes caused by insufficient thrust. The solution is to repair the positioner and pipeline, use a rigid actuator. (7) large amount of leakage: first check the sealing surface is damaged, the valve seat and the valve stem thread is loose, the valve is closed, the pressure difference is greater than the output of the implementing agencies. The solution is to replace the sealing surface, and tight seat, replace the high output force of the implementing agencies. (8) Oscillation phenomenon: It is due to the valve in a small opening work or flow to flow closed type. The solution is to avoid a small degree of work, change the flow of open-type work.