What Is a Thermostatic Radiator Valve?
The radiator constant temperature control valve, the temperature package part and the valve body are integrated into a built-in thermostat.
Radiator thermostatic control valve
- Chinese name
- Radiator thermostatic control valve
- Temperature range
- 8 28
- Working pressure
- 1.0MPa
- Pressure difference
- 0.1MPa
- The radiator constant temperature control valve, the temperature package part and the valve body are integrated into a built-in thermostat.
- First, product selection points
- 1. The main control parameters of the radiator constant temperature control valve are the nominal diameter, the flow coefficient Kv, the maximum working pressure, the maximum working pressure difference, and the maximum water temperature.
- 2. See Table 1 for the classification, characteristics, and application range of radiator thermostatic control valves.
- Table 1 Classification, characteristics and application range of radiator thermostatic control valves
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- 3. Select the type of thermostatic valve according to system type, radiator connection type, and presence or absence of radiator cover, etc., as shown in Table 1. The temperature adjustment range of the thermostatic valve is usually 8 28 , the maximum working pressure is 1.0MPa, and the maximum pressure difference is 0.1MPa.
- 4. The double-pipe system must use a high-resistance two-way thermostatic valve specially designed for the double-pipe system. Single-tube systems generally use low-resistance two-way thermostatic valves.
- 5. Three-way thermostatic valve for single-pipe system (requires that the flow rate entering the radiator is within the range of 0 to 100% and the flow rate across the pipe is within the range of 100% to 0), requiring the adjustment of individual radiators not to affect the same series Flow of other radiators in the system. However, the quality of this type of valve is not stable enough and it is easy to leak water. It is not recommended.
- 6. If both ends of the thermostatic valve exceed the maximum pressure difference, stable adjustment or noise cannot be produced. Therefore, different specifications of the thermostatic valve have a certain range of pressure differential application. Usually when the system is started, or when a large number of users are on duty to regulate or lock, the thermostatic valve of a normal heating user may have overpressure. Therefore, when designing, it is necessary to perform simulation analysis on users and take corresponding measures to ensure the safe operation of the system.
- 7. For small or economic analysis and calculation, the thermostatic valve can work normally, each riser does not need to install a differential pressure control valve. For large-scale systems or pressure differentials that exceed the maximum pressure differential allowed by thermostatic valves, self-operated pressure differential control valves should be installed.
- 8. When the radiator thermostatic valve is used in the indoor heating double pipe system, the valve weight should be calculated, that is, the resistance of the thermostatic valve as a percentage of the resistance of the branch system in which it is located. When designing, the weight of the valve is about 50%; at this time, the thermostatic valve has better regulating performance and lower resistance loss. During calculation, the relationship between the KV provided in the sample data and our commonly used pipeline resistance characteristic coefficient S is as follows:
- 9. Single pipe systems with spanning pipes (including vertical single pipes and horizontal single pipes) should use low resistance two-way thermostatic valves. When using a low-resistance two-way thermostatic valve, the shunt coefficient of the radiator or other heating equipment should be calculated according to the following formula, that is, the flow through the radiator and the total flow through the branch pipe The ratio of the sum of the pipe flows) should be 30%.
- =
- Where: radiator shunt coefficient;
- S1 resistance characteristic number of radiator branch;
- S2 Number of resistance characteristics across branch pipe
- 10. For the heating system operation and poor water quality conditions, in order to ensure the normal operation of the thermostatic valve, it should be at the entrance of each household (household system) or on the riser (existing building with a vertical single pipe system with spanning pipes) ) Or set a water filter in front of the thermostatic valve (generally 60 mesh).
- Related standard diagram
- 05K405 Selection and Installation of New Radiator
- Third, construction and installation points
- 1. Since the thermostatic valve needs to feel the indoor temperature, it must be ensured that the temperature of the thermostat's temperature package part is in a relatively open air space during installation. The temperature sensor of the built-in sensor must be installed horizontally, not vertically. When the sensor is blocked by curtains or other objects, is affected by the surface temperature of the heating pipe, or cannot be installed vertically, a temperature pack of an external sensor must be used. Place it away from curtains and pipes, and connect it to the main valve body through its own capillary.
- 2. The valve body and the pipeline are connected by threads, and the valve core can be replaced without using water in the system (special tools are required). Therefore, there is a corresponding operating space around the thermostatic valve, and it must be firmly connected to the pipes on both sides.
- 4. Thermostatic Radiator Valve Thermostatic Radiator Valve is a special valve used in conjunction with heating radiator for short . It can set the indoor temperature artificially and generate self-acting action by sensing the ambient temperature through the temperature package. It can adjust the flow through without external power The hot water flow of the radiator thus achieves a constant room temperature valve.
- Subjectively: The self-standing adjustment of the valve keeps the room temperature constant and improves the comfort of the indoor environment.
- Objectively: The self-standing adjustment of the valve reduces the system's circulating flow and reduces energy consumption.
- The radiator constant temperature control valve is installed on the water inlet pipe of each radiator. The user can adjust and set the room temperature according to the requirements of the room temperature. According to its working principle, thermostatic valves are proportional controllers, that is, proportionally and smoothly open or close the valves according to the deviation between the room temperature and the set value of the thermostatic valve. The opening degree of the valve is maintained at a position corresponding to the required load, and the water supply amount and the room temperature are stable. Relative to a certain set value, the temperature range of the thermostatic valve from the fully open to the fully closed position is called the proportional band of the thermostatic valve, and usually the proportional band is 0.5 ° C to 2.0 ° C.
- Radiator thermostatic control valves can be classified according to the different temperature-sensing media filled in their temperature packages, which can be roughly divided into the following four categories:
1) The medium filled in the steam temperature-pack type is a low-boiling point liquid. When the external temperature rises, part of the liquid vaporizes into a gas. The volume of the temperature-pack increases, pushing the valve stem, closing the small valve, reducing the opening The flow of water into the radiator. When the external temperature decreases, part of the gas is liquefied into a liquid, the volume of the temperature pack is reduced, and the valve opening is increased, thereby increasing the flow of water into the radiator. The temperature-sensing medium in this temperature pack is often in a gas-liquid mixed state. The advantage is that the action time is fast, but the requirements for the temperature-pack sealing are very strict, and it is rarely used in China.
2) The temperature-sensing medium filled in the liquid temperature-pack type is a special liquid, usually methanol or toluene. This type of warm pack has a large volume and a short action time, and is widely used in China.
3) The solid-state warm-pack type warm pack is filled with a solid with a high expansion coefficient, mostly paraffin. The inverter radiator has a relatively small volume change due to the heating (cold) volume of the solid gas and liquid, so its temperature sensing action is slower, but the volume is smaller than the liquid temperature package, and it is also partially used in China.
4) The temperature sensing device of the metal plate type constant temperature controller is a special alloy metal plate with memory function. This metal plate expands and contracts due to heat, which drives the temperature control valve.
Products need to undergo rigorous experiments and inspections of their temperature sensing devices. At the same time, due to the characteristics of fatigue and fracture after frequent expansion and bending of metals and the ductility of metals, the life and accuracy of such temperature sensing devices Make an impact. [1]