Needle type instrument valves, as a key component of instrument measurement pipeline systems, play a crucial role in the industrial field. It is mainly composed of globe valves and ball valves, and its unique valve core design is a pointed cone that inserts into the valve seat like a needle, hence the name needle type instrument valve.
The main function of this valve in instrument measurement pipeline systems is to open or cut off pipeline pathways. For example, in some precision measurement scenarios, needle type instrument valves can accurately control the flow of media, ensuring the accuracy of measurement results.According to relevant data, needle type instrument valves have advantages such as good sealing and long service life. Even if the sealing surface is damaged, only vulnerable parts need to be replaced to continue use.
When installing needle type instrument valves, the flow direction of the medium should be consistent with the direction of the arrow on the valve body to ensure the normal operation of the valve.Manual globe valves and ball valves can be installed at any position in the pipeline, with high flexibility. Needle type instrument valves have a wide range of applications, not only performing well in the field of instrument measurement, but also having important applications in fields such as flame cutting. For example, the cutting distance used in flame cutting and the knob for adjusting flame temperature often use needle type instrument valves, which can accurately adjust the size and temperature of the flame to meet different cutting needs.
1.Characteristics and advantages of needle type instrument valves
Excellent performance
Needle type instrument valves can withstand high temperature and high pressure environments. For example, it can still operate stably in some high-temperature conditions, such as environments with temperatures up to 570 ℃. At the same time, its non corrosive characteristics are also outstanding, thanks to the correct selection of valve body materials. Although there are abundant materials for corrosion prevention, the problem of corrosion is complex. Needle instrument valves generally use suitable materials such as 20 #, 1Cr18Ni9Ti, 304, 316, 316L, 12Cr1Mov, etc., so that the valve can maintain good performance in various complex medium environments.
In addition, needle type instrument valves are easy to control micro flow rates and add and drop feed, making operation convenient. When precise control of medium flow is required, needle type instrument valves can play their unique advantages by adjusting the position of the valve core to achieve precise control of flow. Moreover, when a malfunction occurs and requires maintenance, the needle type instrument valve is easy to replace and repair. Once the sealing surface is damaged, only vulnerable parts need to be replaced to continue use, greatly reducing maintenance costs and time.
Advanced connection method
As a connection method for needle type instrument valves, sleeve type instrument valves have many advantages. Firstly, the installation and disassembly are convenient, which allows personnel to operate more efficiently during the installation and maintenance process. Tightening the connection ensures that the valve will not loosen during operation, improving the stability of the system.
At the same time, it is beneficial for fire and explosion prevention, and can effectively ensure safety in some flammable and explosive environments. High pressure resistance, with a general working pressure of up to 32MPa or even higher. Good sealing performance can effectively prevent medium leakage and improve the sealing and reliability of the system. This advanced connection method has enabled needle type instrument valves to be widely used in power plants, refineries, chemical plants, and instrument measurement pipelines.
Good sealing performance
One of its significant features is the good sealing performance of needle type instrument valves. In practical applications, even under high pressure environments, it can effectively prevent medium leakage. For example, under a nominal pressure of 32MPa, needle type instrument valves can still maintain good sealing performance.This is thanks to its unique design and high-quality materials. Long service life, even if the sealing surface is damaged, only vulnerable parts need to be replaced to continue using. This design not only reduces maintenance costs, but also improves the reliability and stability of the valve. When installing needle type instrument valves, attention should be paid to aligning the flow direction of the medium with the arrow direction on the valve body to ensure the normal operation and good sealing performance of the valve.
Working principle of needle type instrument valve
The working principle of needle type instrument valves is based on their unique design and structure. Its valve core has a sharp conical shape, which allows it to achieve precise control of fluids in a small space. When the valve core is inserted into the valve seat, a tight seal is formed, effectively cutting off the flow of fluid.
Compared to other types of valves, needle gauge valves can withstand greater pressure. According to relevant information, its nominal pressure can reach different levels such as PN2.5, PN4, PN6.4, PN16, PN32MPa, etc., which can meet the needs of various high-pressure working conditions. At the same time, its sealing performance is good because the contact area between the valve core and the valve seat is small, the sealing force is concentrated, and it can effectively prevent fluid leakage.
In practical applications, needle type instrument valves are generally used for sealing gas or liquid media with lower flow rates and higher pressures. For example, in the measurement pipelines of some precision instruments, precise control of small flow media is required, and needle type instrument valves can play their unique advantages. It can achieve precise adjustment of flow rate by adjusting the position of the valve core, ensuring the accuracy of measurement results.
The combination of needle type instrument valves and pressure gauges is the most suitable. Due to its ability to accurately control the pressure and flow rate of the medium, it provides a stable measurement environment for pressure gauges. General needle type instrument valves are made with threaded connections, which are simple, reliable, easy to install, and can ensure a tight connection between the valve and the pipeline, preventing leakage.
The working principle of needle type instrument valves is to achieve precise control and sealing of fluids through their unique valve core design and structure. It plays an important role in instrument measurement pipeline systems, providing reliable guarantees for precise measurement and control in various industrial fields.
Anti corrosion methods for needle type instrument valves
Anti corrosion measures are crucial for needle type instrument valves when used under various working conditions. Firstly, the correct selection of materials is crucial. If stainless steel, carbon steel and other materials are selected, these materials have good corrosion resistance and mechanical properties.Taking stainless steel as an example, it can maintain stable performance in various corrosive media, such as in environments containing chloride ions, stainless steel can effectively resist corrosion. According to statistics, in some chemical plants, needle type instrument valves made of stainless steel can have a service life of several years or even longer.
Adopting lining measures is also an effective anti-corrosion method. Can be lined with lead, aluminum, engineering plastics, natural rubber, and various synthetic rubbers.
For example, in some pipeline systems with special media, needle type instrument valves lined with fluoroplastics can effectively resist the erosion of highly corrosive media. If the medium conditions permit, this is indeed a cost-effective and effective anti-corrosion method.
Under low pressure and temperature conditions, using non-metallic materials as the main body can often effectively prevent corrosion. For example, needle type instrument valves made of non-metallic materials such as polytetrafluoroethylene perform well in some low-pressure, low-temperature corrosive environments.
The outer surface of needle type instrument valves is generally protected by painting. This not only prevents atmospheric corrosion, but also beautifies the appearance of the valve. Generally, steel materials are coated with paint for protection. Different paints have different anti-corrosion properties, and suitable paints can be selected according to specific usage environments.
By selecting materials correctly, adopting lining measures, using non-metallic main materials, and painting protection, various methods can effectively improve the anti-corrosion performance of needle type instrument valves, extend their service life, and ensure stable and reliable operation under various complex working conditions.
Installation precautions for needle type instrument valves
Installation position and direction
The installation position, height, and inlet/outlet direction of needle type instrument valves must strictly comply with the design requirements. This is the foundation for ensuring the normal operation of valves and the stable operation of the entire system. In the actual installation process, it is necessary to carefully check the design drawings to ensure that the valve is installed in the correct position.At the same time, it should be noted that the direction of medium flow should be consistent with the direction of the arrow marked on the valve body, and the connection should be firm and tight. If the installation direction is incorrect, it may cause the valve to fail to open or close properly, affecting the flow of the medium and even damaging the valve. For example, in some chemical production facilities, due to the special nature of the medium, the installation direction of valves is extremely strict. If the installation direction is incorrect, it may cause medium leakage and lead to safety accidents.
Appearance inspection
Before installing the valve, a visual inspection must be conducted. The appearance inspection mainly includes checking whether there are scratches, rust, deformation and other defects on the surface of the valve, whether the valve nameplate is clear and complete, and whether it complies with the current national standard "General Valve Marking" GB 12220.Through visual inspection, potential issues with the valve during transportation and storage can be identified in a timely manner, ensuring the quality of the installed valve is qualified. For example, if severe rust is found on the surface of the valve, it may indicate that the valve has been affected by a humid environment during storage. At this time, the valve should be replaced in a timely manner to avoid affecting the normal operation of the system.
Strength and tightness test
For needle type instrument valves with a working pressure greater than 1.0 MPa and a cutting effect on the main pipeline, strength and tightness performance tests should be conducted before installation, and they can only be used after passing the tests. During the strength test, the test pressure shall be 1.5 times the nominal pressure, and the duration shall not be less than 5 minutes. The valve shell and packing shall be qualified if there is no leakage.During the tightness test, the test pressure is 1.1 times the nominal pressure; The duration of the experiment should comply with the requirements of GB 50243. Conducting these tests can ensure that the valve can operate safely and reliably under high pressure and complex working conditions. For example, in some important industrial fields such as power plants and oil refining, the strength and tightness requirements for needle type instrument valves are extremely high. Only through strict testing can the safe and stable operation of the system be ensured.
Principles for selecting needle type instrument valves
Select the appropriate type based on the medium and working conditions
1.For pipeline systems and devices for low-temperature media, it is advisable to use low-temperature needle valves with valve covers. For example, in some low-temperature chemical production environments, such as temperatures as low as -20 ℃ or even lower, low-temperature needle valves can ensure the normal flow of the medium and the stable operation of the system. This type of valve is specially designed to effectively resist the impact of low temperature environment on the valve body, preventing problems such as valve rupture or decreased sealing performance due to low temperature.
2.On the pipeline system of the catalytic cracking unit in the refining unit, a lifting rod needle valve can be selected. In the refining process, the working environment of catalytic cracking units is complex and requires high requirements for valves. The lifting rod needle valve can adapt to such complex working conditions, and its unique design can better control the flow and pressure of the medium, ensuring the smooth progress of the refining process.
3.In the equipment and pipeline systems of corrosive media such as acid and alkali in chemical systems, it is advisable to use all stainless steel needle valves made of austenitic stainless steel with polytetrafluoroethylene as the valve seat sealing ring. In the field of chemical engineering, various corrosive media such as strong acids, strong bases, etc. are often encountered. The all stainless steel needle valve is made of high-quality austenitic stainless steel material, which has good corrosion resistance. In addition, the PTFE valve seat sealing ring can further improve the sealing performance of the valve and effectively prevent the leakage of corrosive media.
4.Metal to metal sealed needle valves can be used on pipeline systems or devices for high-temperature media in metallurgical systems, power systems, petrochemical plants, and urban heating systems. In these high-temperature environments, the sealing performance of ordinary valves may be affected, while metal to metal sealed needle valves can withstand temperatures up to 500 ℃ or even higher and maintain good sealing performance.
5.When flow regulation is required, a worm gear transmission, pneumatic or electric regulating needle valve with a V-shaped opening can be selected. This type of valve can accurately adjust the flow rate of the medium according to actual needs, meeting the flow control requirements under different working conditions. For example, in the measurement pipelines of some precision instruments, it is necessary to finely adjust the flow rate, and the regulating needle valve with a V-shaped opening can play its unique advantages.
Selection of Connection Method
1.For the main pipelines of oil and natural gas transportation, those that need to be cleaned and buried underground, needle valves with full bore and fully welded structures should be selected; For ball valves buried on the ground, choose full bore welded connections or flange connections. The needle valve with full bore and fully welded structure has good sealing and pressure resistance performance, which can ensure the safety and reliability of oil and natural gas transportation. For pipelines buried on the ground, ball valves with full bore welded or flanged connections are more convenient for installation and maintenance.
2. For the transportation pipelines and storage equipment of finished oil products, flange connected needle valves shall be selected. The flange connected needle valve is easy to install and disassemble, with tight connections, and can meet the requirements of finished oil transportation and storage processes.
3.On the pipelines of urban gas and natural gas, needle valves with flange connections and internal thread connections are selected. This connection method not only ensures the sealing of the valve, but also facilitates installation and maintenance, making it suitable for the transportation of urban gas and natural gas.
4.In the oxygen pipeline system of the metallurgical system, it is advisable to use needle valves that have undergone strict degreasing treatment and are connected by flanges. In the oxygen pipeline system, in order to prevent the reaction between oxygen and grease, which may cause fire or explosion hazards, needle valves that have undergone strict degreasing treatment must be selected, and flange connections must be used to ensure the tightness and safety of the connection.
Application fields of needle type instrument valves
Needle type instrument valves have been widely used in multiple important industries due to their excellent performance and characteristics.
In the petroleum industry, needle type instrument valves are used to control the flow of various corrosive, high-temperature, and high-pressure fluids. For example, in the process of oil extraction, precise control of the flow and pressure of media such as oil, gas, and water is required. Needle type instrument valves can operate stably under complex working conditions to ensure the safety and efficiency of the production process. According to statistics, the number of needle type instrument valves used in large petrochemical enterprises can reach thousands.
The chemical industry also cannot do without needle type instrument valves. In chemical production facilities, various corrosive media such as strong acids and alkalis are often encountered. The design of all stainless steel needle valves with PTFE valve seat seals can effectively resist the erosion of these corrosive media and ensure the smooth progress of chemical production. Meanwhile, needle type instrument valves can also be used to precisely control the amount of chemical raw materials added, improving product quality and production efficiency.
In the power industry, needle type instrument valves play an important role in the measurement pipeline system of equipment such as boilers and turbines. It can accurately control the flow and pressure of media such as steam and water, providing reliable guarantees for the safe operation of equipment. In some high-temperature and high-pressure environments, such as temperatures up to 540 ℃ and pressures up to 32MPa, needle type instrument valves can still work stably.
In the metallurgical industry, metal to metal sealed needle valves are suitable for pipeline systems in high-temperature media. In processes such as steelmaking and ironmaking, it is necessary to control high-temperature liquid metals and high-temperature gases. Needle type instrument valves can withstand high-temperature environments to ensure the smooth progress of metallurgical processes. In addition, needle type instrument valves can also be used to control the flow of various auxiliary media in metallurgical processes.
The pharmaceutical industry has extremely high hygiene standards for valves, and needle type instrument valves have been widely used in the pharmaceutical production process due to their excellent sealing performance and easy cleaning characteristics. It can precisely control the flow rate and pressure of various drugs, ensuring the stability and consistency of drug quality.
Needle type instrument valves play an irreplaceable role in industries such as petroleum, chemical, power, metallurgy, and pharmaceuticals, providing reliable technical support for the development of various industries.
