Electric Temperature Control Valve
Electric temperature control valve is a typical application of electric flow control valve in the field of temperature control. Its basic principle is to control the outlet temperature of equipment by controlling the inlet flow of heat exchanger, air conditioning unit or other heat and cold equipment and primary heat ( cold ) medium. When the load changes, the flow rate is adjusted by changing the valve opening degree to eliminate the influence caused by load fluctuation and restore the temperature to the set value.
Classification of Siemens Temperature Control Valves
A. Siemens original - electric temperature control valve
B. Mixed installation ( Siemens ) - electric temperature control valve (with valve body manufactured by Shandong chenxuan)
Composition of Siemens Temperature Control Valve
Controller:
Accept the temperature signal and output 0...10V control signal through P/PI/PID operation. Common models of Siemens controllers include RWD60RWD 62RWD68RLU36RMZ730-b, etc.
Actuator:
Accept the adjustment signal sent by the controller, accurately adjust the valve opening, stable operation, optional power-off reset, 3P or analog adjustment, 230DCV or 24DCV power supply. The common models of Siemens actuators are SUA21SQS65SSC85 SAX61SKD62SKB62SKC62, etc.
Valve body:
The executor that regulates the flow of medium is matched with the executor to form an electric regulating valve. Siemens valves are divided into: copper valves, cast iron valves, ductile iron valves, cast steel valves; According to the connection mode, it can be divided into: threaded connection and flange connection valves; According to the medium used, it can be divided into water valve and steam valve. Diameter DN15 ... DN150.(chenxuan DN15-DN400)
Sensors:
The temperature of the medium is measured in various types. According to the installation position, it can be divided into immersion temperature sensor, binding temperature sensor, air duct temperature sensor, indoor temperature sensor, outdoor temperature sensor and other types.
Characteristics of Siemens Temperature Control Valve
Advantages:
A. With proportional integral ( PI ) or proportional integral and differential ( PID ) adjustment functions, the control is stable and accurate.
B. Aiming at different field working conditions, the control parameters can be flexibly adjusted to achieve system optimization.
C. The controller can read the current temperature value and observe the working state of the valve.
D. Extensible functions, such as remote setting, temperature compensation, overtemperature alarm, heat metering, automatic meter reading, remote transmission, etc.
E. Most models can be operated manually when power is cut off.
Features:
1. Siemens temperature control valve controller is easy to install and debug and does not require expensive debugging and field programming costs.
2. The controller automatically adjusts the water flow in the primary valve according to the secondary side outlet water temperature to achieve the effects of comfort and energy saving. The outlet water temperature of the heat exchanger is compensated and changed according to the outdoor temperature, so that users feel comfortable in the use process, and the strange circle that the higher the outdoor temperature is, the higher the indoor temperature is, and the lower the outdoor temperature is, the lower the indoor temperature is is is avoided. On the premise of comfortable use, users can save operating costs, reduce operating costs and obtain considerable economic benefits.
3. According to different use sites, especially unattended workstations, the extension function of multi-function controller can be selected to support the control of water pump, flow rate, pressure difference, and alarm for faults in operation.
4. The valve body adopts advanced pressure feedback device, which solves the problem that the use of electric regulating valve has been affected by high pressure drop for a long time. It has a wide range of applications, can be used for production and automatic control in various industries such as chemical industry, petroleum, metallurgy, electric power and light industry, and is suitable for heat exchange occasions such as air conditioning, refrigeration, ventilation, heat supply, etc.
5. Electric valve actuator adopts patented hydraulic control technology of Siemens Building Technology to realize large thrust, long service life, safety and stability, and can effectively save user investment.
6. Add an outdoor temperature sensor to realize outdoor temperature compensation, which can save energy and reduce operating costs.
Common Knowledge of Siemens Temperature Control Valve Selection
1. The valve material, flow capacity and actuator shutoff force shall be comprehensively considered according to the type of heat medium ( steam / hot water ), temperature, pressure parameters and operating conditions ( heat exchanger type, opening / closing system ).
2. When used for steam flow control, generally refers to 98 % dryness of saturated steam. If it is superheated steam, due to the change of steam adiabatic index k and the corresponding change of fluid viscosity coefficient, it is generally necessary to recalculate and check.
3. The medium flow rate has a square root relationship with the differential pressure before and after the valve. Excessive pressure difference not only produces noise, but also has cavitation effect on valve body, affecting service life. The light ones are not tightly sealed, and the heavy ones may explode, causing casualties and other major accidents.
4. Excellent temperature regulation curve is the guarantee to realize temperature control effect. Except for the special requirements of the fast thermal system, the valve shall be of equal percentage or parabolic type as far as possible.
Equal percentage: q / qmax = r ( l / lmax - 1 )
Parabolic: Q/Qmax=1/[1+ ( r - 1 under radical ) l / lmax ] 2
5. Electric temperature control valve shall not be used as stop valve for a long time. Please shut down when stopping the machine.
6. The two-way valve must not be used as a three-way valve by removing the blind plate on the valve base.
7. When using equipment produced by a third party to match Siemens products, attention should be paid to meeting safety requirements.
8. The temperature control valve cannot use a direct water supply system and must be circulated. If it is an instant heat exchanger, a heat storage tank must be added.
9. When working in domestic hot water, please distinguish between 24 - hour hot water supply and regular hot water supply.
Precautions for Use of Siemens Temperature Control Valve
Influence of Environmental Humidity
1) The allowable environmental humidity of the actuator shall be ≤ 95 % r h, and there shall be no moisture or dew - beware of leakage and leakage of pipelines and equipment in the machine room
2) Pay attention to secondary volatilization of condensed water
3) Keep the machine room ventilated or regularly ventilate and exhaust air.
4) Pay attention to rainproof doors and windows, building leaks
Influence of ambient temperature
1) Allowable ambient temperature of actuator ≤ 55 ℃;
2) Valve body, heat exchanger and pipeline shall be kept warm;
3) Keep the machine room ventilated or take regular ventilation;
4) Avoid direct sunlight.
Faults Caused by Outdoor Installation
1) lcing: outdoor temperature is low in winter. When the equipment is not in use, water will be stored in the interior and the ice will expand.
2) Ultraviolet irradiation: plastic parts and electronic parts are easy to age.
3) Rainwater: Causing PCB Burnout and Metal Rust
4) Dust: PCB fouling, mechanical parts blocking
Precautions for installation location
1) Don't be too high, otherwise it is not convenient for debugging, maintenance and replacement.
2) Avoid the upper pipeline of the regulating valve, especially the pipe flange, slipknot and other pipe fittings, so as not to damage the actuator due to water leakage.
3) Actuator shall be installed on the upper part of valve body to prevent water leakage from damaging actuator.
4) The valve body shall not be installed at the " U" bottom of the pipeline or at the place where the equipment can flow back condensate, so as to avoid water in the valve body of the temperature control valve, causing steam hammer during secondary steam admission.
The equipment starts up and runs.
1) When the equipment is operated for the first time, the temperature control valve will be operated at a sharp full load due to the large temperature increase requirements of the warm pipe and secondary water, resulting in damage;
2) It is recommended to pass steam and water from the bypass, and close the bypass when the secondary side temperature rises close to the set value ( note that the bypass must be closed to death );
3) When the new pipe network and system are put into operation for a period of time, please be sure to clean up the filter so as not to block up steam and water.
4) Pay attention to the operation, the steam valve opens slowly and closes quickly, and the water valve opens slowly and closes slowly.
Maintenance
1) When the temperature control valve is in operation, it shall be checked regularly to eliminate the faults in time.
2) Maintenance after equipment shutdown
3) Maintenance before starting up the equipment
4) When the equipment is out of service for a long time, pay attention to regular inspection to improve the environment of the machine room, and clean and protect the parts prone to dust and rust.
5) It must be operated and maintained by trained professional technicians.
