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A thermostatic valve is a device that is installed on the radiator water supply pipe for temperature regulation (actually flow regulation). It is divided into manual temperature control valve and automatic temperature control valve. Automatic temperature control valve is also called self-operated temperature control valve or automatic thermostatic valve. It is also referred to as thermostatic valve.
The automatic temperature control valve is composed of a self-operated actuator of the temperature sensor and a special matched temperature control valve body. The structure of the temperature control valve body is often the two most common two-way valves, straight through and angled through. Two-way valves are primarily used in dual pipe systems or in specially designed new single pipe systems.
In recent years, according to the differences between single and double pipe systems, graduate students have produced three-type thermostatic valves specifically for single-tube systems and special four-way valves for dark-mounted single and double-tube systems. These four-way valves are now more common in imported products, such as the GIACOMI-NI four-way valve, which is not only suitable for various radiators, but also suitable for single and double pipe systems, and also has the ability to meet The connection of various concealed pipes.
Thermostatic valves are usually available in manual or automatic mode, and the valve operating principle is quite different. The manual temperature control valve usually adopts a spiral lifting valve core, and the rotation of the handle is linearly displaced by the spiral into a spool. In order to adapt to the unique linear movement mode of the self-actuating mechanism of the temperature control sensor, the automatic temperature control valve is usually designed to be linearly displaced by automatic resetting, so the two valve bodies are generally not interchangeable.
However, there are also interchangeable and specially designed valve bodies that can be used universally, that is, a valve body using an automatic temperature control valve, and a suitable manual screw lifting mechanism can be used to realize universal exchange of manual and automatic. This improvement is particularly suitable for China's national conditions and is very practical. In many projects, in order to save the initial investment of the developer, a valve body with automatic temperature control function is attached and a special screw lifting handle is attached. The realization of the manual temperature control valve with 1/3 of the automatic temperature control valve cost (this price is basically equivalent to the manual temperature control valve), and the user to achieve automatic temperature control in the future to leave the upgrade space.
This kind of product is rare even in imported products. Italy's Jecomini is in front of the market in this respect, providing a kind of double adjustment between the manual and automatic temperature control valves. Thermostatic valve, eight-speed setting, indoor temperature is set with your convenience. It is worthy of being the world's largest supplier of HVAC valves. Because of the particularity of the valve between the manual and automatic temperature control valves, the choice will be more complicated, and this complexity creates opportunities for some unskilled personnel and speculative salesmen to "make the eye".
In the current market, there are many suppliers of automatic temperature control valve suppliers who recommend a pure automatic temperature control valve body with a simple adjustment handle as a temperature control valve with dual adjustment function, and some users adopt this method. The temperature control valve, this is not very suitable, there is a big hidden danger, such a simple temperature control valve body with a simple adjustment handle, but the design of the handle is to meet the automatic temperature control valve Before the valve head is installed, it is temporarily used for system adjustment to meet the engineering test pressure test. After the test pressure test process is completed, it is replaced by the automatic temperature control valve head. Due to its temporary nature, the simple adjustment is made. The handle borrows the original thread used to fix the temperature-controlled valve head on the valve body for screw lifting.
We all know that the simple adjustment handle is usually made of plastic because of its temporary and disposable. If it is used as the final frequent adjustment, the thread wear will be very fast, not to mention the upper and lower of the spool when the heating system is working normally. The lifting is carried out under a certain pressure. Even in the system without pressure, the spring pressure of the valve core itself will greatly accelerate the wear of the handle thread, so the product can be upgraded to an automatic temperature control valve. Manual temperature control valves are not appropriate.
Italy's Gecomini's temperature-controlled valve, which can be upgraded to an automatic temperature-controlled valve, is a double-regulated temperature control valve. The biggest difference from other brands is that its adjustment handle is not a temporary one-off product, but is designed to be durable. The final product of the application, the thread shape of the spiral lifting thread is a specially designed trapezoid with a wear resistance of 4.5 mm. There is no worries about long-term use, of course, there is no problem with temporary use. The thread borrowed by the general temporary adjustment handle is a fine tooth fixing thread, and the thread shape of the thread is a common triangle, and the pitch is only 1.5 mm. This temporary handle rotates three times
The displacement of the spool can be equivalent to a trapezoidal thread with a 4.5mm pitch, which means that it takes three times longer to open the valve from minimum to maximum, which is obvious for inconvenient adjustment of thermostat valves that often require adjustment. of.
Let us study the automatic temperature control valve. The automatic temperature control valve is usually divided into two parts: the valve body and the valve head. The valve body is generally produced by copper casting or hot forging. The temperature sensor of the valve head generally has liquid and solid points: There are two types of solids: one is wax and the other is thermal memory alloy. Most of the solid sensor media currently on the market are paraffin, and there are few thermal memory alloys.
The following is a brief introduction of the valve body and the valve head, which are common in the market, for reference when selecting the automatic temperature control valve. Temperature control valve body: The advantage of copper casting is that it can cast complex products with complex cavity, less mold cost and lower production cost, but the disadvantage is that there are many casting defects and the material withstand pressure is poor; in contrast, the copper forged valve body is due to the mold. The value is high, the forging equipment is complicated, the production cost is high, but the high-strength product can be obtained, and the pressure resistance is much higher than that of the casting, and the casting defects are effectively avoided.
Therefore, for valve bodies with less complicated shapes, professional manufacturers use hot forging to produce valve bodies. However, some manufacturers use casting to produce, which requires careful identification by the user. I think that the temperature control valve used in the heating is a simple valve body, and hot forging is very suitable. There is another detail when selecting the valve body. It should be noted that many valve bodies are designed to be simpler. The valve body inlet and outlet of the straight-through valve are on the same axis. This design is simple, but the displacement space of the valve core will be affected. Influence, so the valve body spool displacement is generally only 2-3mm.
Italy's Gecomini's automatic temperature control valve body, its straight-through valve body design is very unique, in the case of ensuring that the outlet and the inlet are in the same axis, the inner cavity channel adopts a misalignment design, which effectively increases the displacement space of the valve core, so that The displacement of the spool is as high as 4-5mm, which is rare in the design of automatic temperature control valves. The increase in spool displacement is very advantageous for dirty HVAC water quality, and too small spool displacement will be prone to blockage in the case of dirty warm water and severe fouling.
Thermostatic valve head: The internal charge medium of the temperature sensor in the temperature control valve head generally has two kinds of liquid and solid. The liquid and solid are different in the production process. Generally, the manufacturer usually adopts the limitation of the production scale, and often only adopts the medium. A process to produce liquid or solid valve heads, only a few large manufacturers will produce two valve heads at the same time to facilitate customer choice.
As for the difference between the two valve heads, I think there should be no difference in the field of HVAC applications. If you have to say something different, I think in the following aspects:
First, the volume is different. Generally, a liquid needs a relatively large amount of liquid to achieve the same thermal expansion displacement. Therefore, the temperature sensor has a large volume, so the valve head has a large volume, which is somewhat inconsistent with the ratio of the small valve body. Therefore, it is better to use a solid type valve. The head is more beautiful.
Second, the liquid sealing technology is more complicated, and the production cost is slightly higher than the solid one, so the selling price is often higher.
Third, the liquid valve head is more sensitive than solids. This is the only advantage of liquid compared to solids, but in the typical large hysteresis system of the HVAC field, this advantage has little effect. All in all, the temperature-controlled valve head, whether liquid or solid, can fully meet the sensitive time requirements of the EN215 standard as long as it is a qualified product.
I have conducted a comparative measurement of the temperature sensors of the two media of Italy's Jecomini in the National Construction Engineering Quality Testing Center, and found no significant difference. It is worth mentioning that the installation of the temperature-controlled valve head of Italy's Gecomini is also very unique. The installation of the general temperature-controlled valve head is threaded, and the company uses its own patented technology, fast card. The pressure connection is fast and safe, effectively avoiding the defect that the manual threaded connection is easy to loose. On the joint joint of the valve body, Jecomini also has its own patent, that is, the PTFE self-adhesive material is burned on the connected joints, which facilitates the installation without entanglement of raw materials or hemp ropes, which effectively improves the installation. The efficiency of the installation and the effective sealing.
In summary, when you want to use the temperature control valve, you should carefully select it, so you can use the least amount of money to make the best choice, whether it is manual, double adjustment or fully automatic temperature control valve, Italy Gecomini It is a perfect choice of partners, complete products, and thoughtful service, so that you can be satisfied.
Generally speaking, if the principle of investment is the most economical, the benefits of automatic temperature control valve energy saving are not considered, and if it is not upgraded to an automatic temperature control valve in the future, a pure manual temperature control valve can be selected. If you use a small investment, considering that the owner will upgrade to an automatic temperature control valve in the future, then you can choose a dual-regulated temperature control valve. This double-regulated temperature control valve is basically the same price as a pure manual temperature control valve. If you want to make a one-step choice, you can directly choose the automatic temperature control valve, the price is roughly three times that of the manual temperature control valve.
How to choose a low price and high quality thermostatic valve
With the reform of the heating system, the household heat metering and compartment temperature control have begun to enter the implementation stage. It is very common to install the temperature control valve on the radiator. The temperature control valve can realize the temperature control of the compartment, which can maximize the temperature. Saving energy, and maximizing the needs of different users for indoor temperature regulation, is a good thing for the country and the people, but how to choose the temperature control valve is not completely user-controlled, if you can not correctly choose the product, not only can not Meet the demand, and may bring unnecessary economic losses to the user, here to introduce you to some choices.