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Introduction and explanation of four common high-temperature valves 1. Selection considerations and application features of high-temperature globe valves. The main advantage of high-temperature globe valves is their ability to withstand high temperatures and pressures. When the valve disc opens and closes, the friction between the sealing surfaces of the valve body is less than that in ordinary gate valves; as a result, these valves exhibit good wear resistance and a long service life. Below, we will discuss the application features of high-temperature globe valves as well as how to select them. I. Application Features 1. Compared to gate valves, the opening height of the valve seat passage in globe valves is smaller; it is only 1/4 of the diameter of the passage. Therefore, globe valves are often used in pipelines with small diameters, while high-temperature globe valves are employed in high-temperature and high-pressure environments where the pipeline diameter is also small. 2. The high-temperature stop valve has only one sealing surface, making it simple to manufacture and easy to maintain. II. How to select the right valve Choosing the appropriate valve is a challenging task, as there are many types of valves available for use in piping systems: gate valves, globe valves, ball valves, plug valves, balance valves, butterfly valves, and so on. Under what circumstances should a high-temperature globe valve be used? 1. High-temperature stop valves are typically used in pipeline systems that transport high-temperature and high-pressure media, such as in urban heating and water supply systems. 2. For pipe connections with small diameters (nominal diameter of 50 millimeters or less), use small-sized high-temperature stop valves, such as instrument valves, pressure gauge valves, needle valves, etc. 3. In pipeline systems where strict requirements are not imposed on the fluid flow resistance, pressure regulation, and flow rate control, and where high precision in regulation is not necessary. 4. High-temperature stop valves are available in various material types, which can be used to shut off the flow of different media such as water, nitric acid, and urea in pipelines. A high-temperature globe valve is a type of valve with structural characteristics and application scenarios that differ from those of other valve types; when purchasing one, it is essential to pay attention to the material and specifications of the globe valve. 2 How to determine whether the sealing performance of high-temperature gate valves meets the standards? Gate valves use a gate as the component used for opening and closing. When assessing whether an industrial valve is of satisfactory quality, sealing performance and pressure are two very important indicators. So, how exactly can we determine whether a high-temperature gate valve is qualified? Now, let me take you through it. I. Intermediate pressure testing: There are specialized sealing tests to verify the sealing performance of gate valves, such as intermediate pressure testing. For the intermediate pressure testing method, first open the valve disc of the high-temperature gate valve and carry out related operations; once the pressure inside the gate valve reaches the standard value, lower the valve disc, then remove the high-temperature gate valve from the pipeline and check the sealing areas to determine if there are any leaks. In addition to conducting simulated tests by placing the gate valve in the pipeline, it is also possible to directly open the top cover of the gate valve, inject a liquid medium to the standard volume, and then check whether there is any leakage of the medium on either side of the high-temperature gate valve. The absence of leakage indicates that the gate valve has good sealing properties. II. Precautions for the test: For the results obtained from the intermediate pressure testing to be accurate, the following points must be observed: 1. During the testing process, the high-temperature gate valve must be filled with a medium, and this medium has to be liquid, such as water or kerosene, in order to achieve the specified pressure level inside the valve chamber. 2. The sealing surface of the gate valve and the sealing areas on both sides should be kept clean; care should be taken to avoid being scratched by the edges during operation. 3. High-temperature gate valves are used in pipelines; if the direction of medium flow has been specified, then pressure testing should also be carried out in accordance with that direction of flow. 4. The intermediate pressure testing method for checking the sealing performance of valve assemblies has certain limitations; it is only suitable for checking gate valves with a nominal diameter of DN32 or larger. In summary, the intermediate pressure testing method can be used to verify whether the sealing performance of high-temperature gate valves is satisfactory; it is particularly necessary to master these testing methods when there are concerns regarding the quality of the gate valves purchased. 3 What are the design features of high-temperature butterfly valves? High-temperature valves are essential fluid control devices, and as industrial production places an increasing demand for such valves, a variety of types are available on the market, including high-temperature globe valves, high-temperature gate valves, and high-temperature butterfly valves. Below we will discuss the design features of high-temperature butterfly valves. I. The valve body wall has excellent pressure resistance. In addition to withstanding high temperatures, high-temperature butterfly valves also possess strong resistance to high pressures. When designing the wall of the butterfly valve, in addition to using materials resistant to high temperatures, attention is also paid to the design of the shell thickness to ensure it can withstand sufficient pressure. High-temperature butterfly valves of different specifications have distinct pressure tolerance values for their housings. These values are determined based on the pressure generated when the fluid medium fills the valve chamber, ensuring that the valve body can withstand such pressure effectively and reducing the likelihood of corrosion of the valve walls. II. Valve body material: The selection of the material for the valve body of high-temperature butterfly valves must meet requirements regarding pressure resistance, hardness, impact resistance, wear resistance, and corrosion resistance; high-temperature valves have strict demands on the materials used in their construction. In high-temperature and high-pressure environments, the likelihood of valve damage increases. To ensure that the valves can function properly in such conditions, materials such as high-temperature alloy steel, carbon steel, and stainless steel can be used, with surface welding treatments applied to make the valve bodies more resistant to wear and cavitation. III. Mandatory sealing in the middle section: The mandatory sealing system consists of a sealing ring, a valve body, and a floating valve cover. High-temperature butterfly valves are designed with this mandatory sealing mechanism, which enhances the sealing performance of the valve body and makes them suitable for use in high-pressure and high-temperature environments. Structure determines function; the difference between high-temperature butterfly valves and high-temperature valves, as well as ordinary valves, lies in their structural design, material selection, and construction, which enable them to function properly in high-temperature and high-pressure environments. 4 What is a high-temperature check valve, and what are its working principles? A high-temperature check valve is a type of industrial valve; it prevents fluid media from flowing in reverse by allowing flow in only one direction. It is primarily used in pneumatic or hydraulic systems. Below, we will take a closer look at high-temperature check valves. I. What is a high-temperature check valve? A check valve is used in pneumatic systems to prevent large amounts of compressed, high-temperature and high-pressure steam from flowing back into the evaporation equipment in the event that the air compressor stops suddenly, thereby avoiding any impact on the cooling efficiency of the evaporation equipment. Check valves are used in hydraulic systems to control the one-way flow of liquid media and prevent backflow. A high-temperature check valve is a device designed for use in special high-temperature and high-pressure environments. Its operating principle is the same as that of a regular check valve, but its valve body is made from materials resistant to high temperatures and pressures, giving it greater resistance to heat, pressure, and impact compared to ordinary check valves. II. Working principle of the high-temperature check valve 1. When the flow direction of the refrigerant in the pipeline is consistent with the throttling direction of the high-temperature check valve, it pushes the limit ring inside the valve, causing the check valve to open; once the valve is open, the refrigerant can flow through it. 2. When the flow direction of the refrigerant is not consistent with the throttling direction of the high-temperature check valve, the valve is in a blocking state at this time; the valve needle does not move, and the refrigerant cannot pass through the valve. 3. In the entire air-conditioning pneumatic system, during cooling the check valve opens, allowing the refrigerant to flow smoothly through the check valve and the main capillary tube, thereby enabling cooling. During heating, the check valve closes to block flow; the refrigerant cannot pass through the check valve and can only be used for heating via the auxiliary capillary network. The above is an introduction to high-temperature check valves. These valves allow the flow of fluid in only one direction; when closed, they prevent the fluid from passing through or from flowing in the reverse direction.