What Is a Solenoid Assembly?

SMC solenoid valve is a commonly used solenoid valve manufactured by SMC. The SMC solenoid valve has various models and is widely used, but it has higher requirements on the cleanliness of the medium.

SMC Solenoid Valve

Today,

1. The main features of SMC solenoid valve: The solenoid valve is leak-proof and leak-proof, and the leak is easy to control and safe to use. Internal and external leaks are a threat to safety. Other automatic control valves usually extend the valve stem, and the rotation or movement of the valve core is controlled by electric, pneumatic and hydraulic actuators. This must solve the problem of external leakage of the long-term action valve stem dynamic seal; only the solenoid valve is completed by the electromagnetic force acting on the iron core sealed in the magnetic insulation sleeve of the electric regulating valve, and there is no dynamic seal, so the leakage is easy to be blocked .

2. The torque control of electric valve is not easy, it is easy to produce internal leakage, and even the head of the valve stem is broken; the structure of the solenoid valve is easy to control internal leakage until it reaches zero. Therefore, the use of solenoid valves is particularly safe, especially suitable for corrosive, toxic or high and low temperature media. 3, SMC solenoid valve system is simple, it will be connected to the computer, the price is low. The solenoid valve itself has a simple structure and a low price, and is easier to install and maintain than other types of actuators such as regulating valves. What is more remarkable is that the automatic control system is much simpler and the price is much lower.

4. Since the solenoid valve is controlled by a switch signal, it is very convenient to connect with an industrial computer. In today's era of popularization of computers and sharply lower prices, the advantages of solenoid valves are even more obvious. The SMC solenoid valve operates with express delivery, with small power and lightweight appearance.

The solenoid valve response time can be as short as a few milliseconds, and even pilot operated solenoid valves can be controlled within tens of milliseconds. Due to its own circuit, it is more sensitive than other automatic control valves.

5. Properly designed solenoid valve coils have very low power consumption and belong to energy-saving products. They can also trigger the action and automatically maintain the valve position, which usually consumes no power at all. The small size of the solenoid valve not only saves space, but also is light and beautiful. The adjustment accuracy of the solenoid valve is limited, and the applicable medium is limited.

6. Solenoid valves usually only have two states of on and off. The valve core can only be at two extreme positions and cannot be adjusted continuously.

7. The SMC solenoid valve has high requirements for the cleanliness of the medium. Granular media cannot be used. If it is an impurity, it must be filtered first. In addition, viscous media cannot be used, and the viscosity range of media for specific products is relatively narrow.

8, SMC solenoid valve models are diverse and versatile. Although the solenoid valve has inherent disadvantages, its advantages are still very prominent, so it is designed into a variety of products to meet various needs and has a wide range of uses. The advancement of solenoid valve technology also revolves around how to overcome the inherent deficiencies and how to make better use of the inherent advantages.

SMC's quality standards are global. SMC (China) is the first company in China's pneumatic industry to pass the ISO14001 environmental management system certification. Someone was right

SMC Corporation started to invest and build factories in Beijing in September 1994. At that time, the total investment was 2 billion yen, and the first factory with an area of 20,000m2 was established. In the Beijing Economic and Technological Development Zone, the construction of the second plant started before the completion of the first plant of SMC. The second plant covers an area of 60,000 m2, which is equivalent to three times that of the first plant. Over the past few years, SMC (China) seems to be a racer against itself, constantly increasing investment, with a total investment of 12 billion yen and a registered capital of 10 billion yen. SMC's strategy is simple: build a plant, introduce advanced equipment, train a group of talents, and consolidate first-class performance. The site of the third plant that SMC is building next is selected in Beijing Tianzhu Export Processing Zone, which covers an area of 180,000 m2, which is equivalent to 45% of the entire export processing zone. In order to strengthen technical support and after-sales service for customers, SMC (China) has established business offices in 13 major cities including Shanghai, Nanjing, Wuxi, Tianjin, Harbin, and Xi'an.

June 1993-Pneumatic Technology Centers were established in Tsinghua University, Beijing Institute of Technology, and Harbin Institute of Technology

September 1994-SMC (China) Co., Ltd. was incorporated

March 1995-Business Department of SMC (China) Co., Ltd. was established

June 1995-Groundbreaking of the No. 1 factory building of the first factory

June 1996-No. 1 building of the first factory was completed, and CYL production equipment was moved in

July 1996-The first cylinder MBB80-100 was born

September 1996-The first batch of cylinders was exported to Japan

January 1997-The second factory was established, the second factory building No. 2 and the second factory building No. 1 and 2 were completed

August 1997-Completion of SMC Beijing staff quarters

September 1997-opening ceremony of SMC's Beijing plant

August 1999-The first batch of cylinders was exported to the United States

September 1999-passed ISO9002 quality system certification

October 1999-The third factory building of the second factory was completed and the FRL production equipment was moved in

December 1999-The first cylinders were exported to Europe

April 2000-The first FRL product AR10-M5 was born

August 2000-The first FRL products were exported to Japan

August 2000-Groundbreaking of the No. 4 and No. 5 Plants of the Second Factory started

August 2000-Purchase of 180,000 square meters of land in the third factory

October 2000-Establishment of Pneumatic Technology Center of Nanjing University of Science and Technology

June 2001-Construction of No. 4 and No. 5 of the second factory was completed

October 2001-Groundbreaking of the third and first factory buildings

November 2001-passed ISO14001 environmental management system certification

January 2002-passed ISO9001 (2000 version) quality management system certification

March 2002-named as one of the top 100 industrial foreign investment enterprises in Beijing

March 2002-named as one of the top 500 industrial system exporters in 2001

June 2002-Shanghai Branch was established

June 2002-Shanghai Pudong Thermostat Technical Support Center was established

October 2002-SMC Shanghai Jiaotong University Pneumatic Technology Center was established

February 2003-2001-2002 Beijing International Economic and Trade Cooperation Award from the People's Government of Beijing

April 2003-was rated as the spiritual civilization unit of the capital

June 2003-Selected as the 5 largest export enterprises and 5 actual foreign investment enterprises in Beijing Economic and Technological Development Zone

August 2003-Selected as the advanced unit for the prevention and treatment of atypical pneumonia in Beijing

May 2004-Land signing ceremony of Shanghai Branch held

July 2004-In the 2003 China Top 500 Machinery Enterprise List, SMC (China) Co., Ltd. was listed as the only representative of the pneumatic industry (333)

September 2004Foundation Ceremony of SMC (China) Co., Ltd. R & D Center

September 2004-Based on the results published by the Japan Economic News on September 21, 2004, SMC ranked 32nd among the top 300 Japanese companies in 2004

2005-The foundation stone of the fourth plant in Beijing was laid, and "SMC China" was named "2005 Top 500 Chinese Machinery Enterprise"

2006-SMC China "was named" 2006 China Top 500 Machinery Enterprise "

2007-SMC China "was named" 2007 Top 500 Chinese Machinery Enterprises "

2008-SMC China "was named" 2008 Top 500 Chinese Machinery Enterprises "." SMC Corporation "was named" 2008 Top 500 World Machinery Enterprises (Ranking 409) "

The SMC solenoid valve is an automatic basic component used to control fluids and belongs to the actuator; it is not limited to hydraulic and pneumatic. Solenoid valve is used to control the direction of hydraulic flow. The mechanical devices of the factory are generally controlled by hydraulic steel, so solenoid valves are used. Solenoid valve is industrial equipment that is controlled by electromagnetic. It is used in industrial control system to adjust the direction, flow rate, speed and other parameters of the medium. There are many kinds of solenoid valves. Different solenoid valves play different roles in the control system. The most commonly used Check valves, safety valves, directional control valves, speed regulating valves, etc. Solenoid valves are controlled by electromagnetic effects, and the main control method is controlled by relays. In this way, solenoid valves can be used with different circuits to achieve the desired control. And the accuracy and flexibility of control can be guaranteed. The rod-shaped object in the picture is the valve stem controlled by electricity, and the valve stem can be opened or closed by using electromagnetic force. The pneumatic system is taken as an example to illustrate the solenoid valve in industrial control. The so-called pneumatic system is a control system with gas as the medium. In the pneumatic system, the medium of this energy is usually air. When it is actually used, the volume of air in the atmosphere is usually compressed to improve its Pressure. Compressed air mainly works by acting on pistons or vanes. In pneumatic systems, the role of the solenoid valve is to control the system according to the requirements of the control. To adjust the various states of compressed air, the pneumatic system also needs the cooperation of other components, including power components, actuators, switches, display equipment and other auxiliary equipment. Power components include various compressors, and actuators include various cylinders. These are indispensable parts of the pneumatic system, and the valve body is an important device for implementing the control algorithm. For example, the check valve allows compressed air from the compressor to enter the air tank, and prevents the compressed air from flowing in the opposite direction when the compressor is turned off; Safety valve can discharge compressed air when the pressure in the gas storage tank exceeds the allowable limit; the directional control valve controls the direction of movement by alternately pressurizing and exhausting the two interfaces of the cylinder; the speed regulating valve can easily implement the actuator Stepless speed regulation. Air circuit system: Oil circuit system: Refrigeration system: A Intake filter J Fuel tank PB Refrigeration compressor air inlet valve K Thermostatic bypass valve Q Condenser C Compressor host L Oil cooler R Thermal Exchanger D Non-return valve M Oil filter S Bypass system EF Air / oil separator N Return valve T Air outlet filter minimum pressure valve O Shutoff valve G After cooler H Water with automatic trap Schematic diagram of the pneumatic system of the separator.The solenoid valve can be used not only in the pneumatic system, but also in the oil pressure system and the water pressure system.The same or similar applications can be obtained, such as low power non-oil supply small electromagnetic directional valve, seals. No need for oil supply, the exhaust gas will not pollute the environment, and it can be used in food, medicine, electronics and other industries. The combination of electromagnetic reversing valve, solenoid valve technology and control technology, computer technology, electronic technology has been able to perform a variety of complex Control. For example, the solenoid valve can be applied in the field of intelligent control and wireless control technology. Because the solenoid valve can be controlled by electromagnetic, it can interface well with various electronic systems, which is also widely used. One of the main reasons for application. Solenoid valves have been widely used in various fields of production. With the improvement of electromagnetic control technology and manufacturing processes, solenoid valves can achieve more sophisticated control. In order to achieve different pneumatic systems, hydraulic systems make use of it. The working principle of the solenoid valve: The working principle of the solenoid valve: There is a closed cavity in the solenoid valve, there are through holes in different positions, each hole is It leads to different oil pipes, the valve is in the middle of the cavity, and there are two electromagnets on both sides. Which side of the magnet coil is attracted to which side the valve body is attracted. By controlling the movement of the valve body, different oil drains are blocked or leaked. Hole, and the oil inlet hole is always open, the hydraulic oil will enter different oil discharge pipes, and then push the oily piston through the oil pressure, the piston will drive the piston rod, and the piston rod will drive the mechanical device. The electrical current of the iron controls the mechanical movement.

1: There are two types of direct-acting solenoid valves: normally-closed and normally-open. Normally-closed is closed when the power is off. When the coil is energized, electromagnetic force is generated, which makes the moving iron core overcome the spring force and directly attract the static iron core. Open the valve, the medium is a path; when the coil is powered off, the electromagnetic force disappears, the moving iron core is reset by the force of the spring, and what is the role of directly closing the SMC solenoid valve, the valve port and the medium are not connected. The structure is simple and the action is reliable. Normal operation under zero pressure difference and micro vacuum. Normally open type is just the opposite. For example, the solenoid valve with a flow diameter less than 6. (Figure 1 is a typical structure diagram)

Second, the step-by-step direct-acting solenoid valve This valve uses a primary valve and a secondary valve to connect together. The main valve and the pilot valve step by step make the electromagnetic force and pressure difference directly open the main valve port. When the coil is energized, it generates electromagnetic Force the moving iron core and the static iron core to attract, the pilot valve port is opened and the pilot valve port is set on the main valve port, and the moving iron core and the main valve core are connected together, and the pressure in the upper cavity of the main valve passes the pilot valve port. Unloading, the main valve core moves upward under the simultaneous action of pressure difference and electromagnetic force, and the main valve medium flows. When the coil is powered off, the electromagnetic force disappears, and the moving iron core closes the guide under the action of its own weight and spring force. Valve hole, at this time, the medium enters the upper cavity of the main valve core in the balance hole, which makes the upper cavity pressure increase. At this time, the main valve is closed under the action of spring return and pressure, and the medium is cut off. The structure is reasonable, the action is reliable, and it is at zero. Reliable operation under pressure difference. For example: ZQDF, ZS, 2W, etc. (Figure 2 is a typical structure diagram)

Third, indirect pilot-operated solenoid valve This series of solenoid valve is formed by the combination of the pilot valve and the main spool to form a channel; normally closed type is closed when no power is applied. When the coil is energized, the generated magnetic force causes the moving iron core Attracting with the static iron core, the pilot valve port is opened, and the medium flows to the outlet. At this time, the pressure in the upper cavity of the main valve core is reduced, which is lower than the pressure on the inlet side, and a pressure difference is formed to overcome the resistance of the spring and then move upward to open the main valve port. When the coil is de-energized, the magnetic force disappears, and the moving iron core resets and closes the pilot port under the force of the spring. At this time, the medium flows in from the balance hole, the pressure on the cavity of the main spool increases, and Under the action, it moves downward and closes the main valve port. The principle of normally open is just the opposite. For example: SLA, DF (diameter above 15), ZCZ, etc. (Figure 3 is a typical structure diagram) Selection of solenoid valve 1: Applicability pipe The fluid in the circuit must be the same as the medium calibrated in the selected solenoid valve series. The temperature of the fluid must be lower than the calibration temperature of the solenoid valve. The allowable liquid viscosity of the solenoid valve is generally below 20CST, and the pressure greater than 20CST should be specified. Working pressure difference, When the maximum pressure difference of the pipeline is less than 0.04MPa Direct-acting and step-by-step direct-acting types such as ZS, 2W, ZQDF, ZCM series are used; when the minimum working pressure difference is greater than 0.04MPa, a pilot-operated (pressure difference) solenoid valve can be selected; the maximum working pressure difference should be less than that of the solenoid valve Maximum calibration pressure; general solenoid valves are one-way work, so pay attention to whether there is a back pressure difference, if a check valve is installed. When the fluid cleanliness is not high, a filter should be installed in front of the solenoid valve. General solenoid valves require media Cleanliness should be good. Pay attention to the flow aperture and the diameter of the connection; solenoid valves generally only have two switches to control; if possible, please install a bypass pipe for easy maintenance; when there is a water hammer phenomenon, customize the opening and closing time of the solenoid valve. Pay attention to the environmental temperature. The influence of the solenoid valve on the power supply current and power consumption should be selected according to the output capacity. The power supply voltage is generally allowed to be about ± 10%. It must be noted that the VA value is higher when the AC is started. Second, the reliability solenoid valve is divided into two types: normally closed and normally open; Normally closed type is used, power is turned on, and power is turned off. However, when the opening time is long and closed, the normally open type is used for a short time. Life test, factories generally belong to type test items, to be precise, there is no solenoid valve in China. Special Standard, so be careful when selecting solenoid valve manufacturers. When the action time is short, the direct-acting type is generally selected when the frequency is high, and the fast series is selected for the large diameter. Third, the general solenoid valve is not waterproof. When the conditions do not allow, please choose a waterproof type, The factory can customize. The highest nominal pressure of the solenoid valve must exceed the highest pressure in the pipeline, otherwise the service life will be shortened or other accidents will occur. All corrosive liquids should be stainless steel, and highly corrosive fluids should be plastic. King (SLF) solenoid valve. Explosion-proof environments must choose the corresponding explosion-proof products. Fourth, there are many solenoid valves that can be used universally, but the most economical products should be selected on the basis of meeting the above three points

I. Applicable control accuracy

a. Action time: refers to the time from when the electrical signal is turned on or off to the completion of the main valve action. Only the company's patented multifunctional solenoid valve can adjust the opening and closing time separately, which can not only meet the control accuracy requirements, but also prevent water hammer . b. Ordinary solenoid valve has only two positions, on and off. When high control accuracy is required and parameters are required to be stable, please select a multi-position solenoid valve.

c. Leakage value The leakage value given on the sample is a common economic grade. If it is too high, please make a special order.

Applicable power supply

a. According to the type of power supply, AC and DC solenoid valves are selected. In general, AC power is easy to access.

b. For voltage specifications, AC220V.DC24V is preferred.

c, power supply voltage fluctuations usually choose +% 10% .- 15% for AC, DC allow ±% 10 or so, if it is out of tolerance, you must take voltage stabilization measures or make special orders.

d. The rated current and power consumption should be selected according to the power supply capacity. It should be noted that the VA value is higher when the AC is started. When the capacity is insufficient, the indirect pilot solenoid valve should be preferentially selected.

Applicable environment

a. The maximum and minimum temperature of the environment should be selected within the allowable range, and special orders should be made if there is any excess.

b. Waterproof solenoid valve should be selected in the environment with high relative humidity and water drops and rain.

c. There are often vibration, bumps and shocks in the environment. Special varieties should be selected, such as marine solenoid valves.

d. For use in corrosive or explosive environments, it is preferred to choose corrosion resistance according to safety requirements.

e. If the environmental space is limited, please choose a multi-function solenoid valve because it eliminates the bypass and three manual valves and facilitates online maintenance. Applicable medium:

1. Different types of solenoid valves are used in the gas-liquid or mixed state.

2. Medium temperature products with different specifications, otherwise the coil will burn out and the seals will age, which will seriously affect the service life. The medium temperature should be selected within the allowable range of the solenoid valve.

3. Medium viscosity, usually below 50cSt. If this value is exceeded, a high-viscosity solenoid valve with a diameter of less than 15mm is ordered.

4. When the medium cleanliness is not high, a backwash filter valve should be equipped in front of the solenoid valve. If the medium is in a directional flow, no reverse flow is allowed.

Fourth, the applicable pipeline:

a. Select the valve port and model according to the requirements of the medium flow direction and the pipe connection method.

b. Select the nominal diameter according to the flow rate and the valve Kv value, or choose the same diameter as the pipe.

c. Working pressure difference The minimum working pressure difference above 0.04Mpa is optional with the indirect pilot type; the minimum working pressure difference close to or less than zero must use the direct-acting or step-wise direct type.

If the SMC solenoid valve suddenly has a problem and there are no replacement parts, the following methods can be used for emergency treatment: 1. Turn the solenoid valve connector by hand until you hear a "click", press and hold The connector is then tightly wrapped with adhesive tape, and then the input line plug is pulled out for a one-touch one-off test. If there is a "click, click" action sound, it indicates that it has returned to normal and can continue to be used. Note that the above process should be performed when the ignition switch is turned on.

2. If it is confirmed that the idling solenoid valve is damaged, it is to restore the idling effect. The solenoid valve should be removed and blocked with a suitable screw plug to prevent air leakage. In this way, the solenoid valve loses its function and becomes a carburetor without an idle solenoid valve.

What does the dm * 3 / (S.bar) unit of sound velocity conductance on the SMC solenoid valve mean? Is it a unit of air velocity? There are also known cylinder specifications. Is the solenoid valve selected based on the cylinder bore? It is known that the solenoid valve is 2-position and 5-way according to the action. How to select the solenoid valve and how to select the decompression valve depends on what the solenoid valve is. Decompression valve, what other components do you need to choose? The equipment is operated in a normal environment. The cylinder bores are two 25mm and one 40mm cylinders. What other components are needed, such as air dryer, cold dryer, moisture separator, oil mist? Do you need a separator?

Need to calculate the flow through the cylinder, select the solenoid valve, and then determine the pressure reducing valve. If the compressed air comes directly from the air compressor, you need a dryer, a moisture separator, an oil mist separator, and so on. If the gas quality is good, you can install a triple piece without increasing the cost. Recommended SMC brand, cost-effective, but imported parts are more expensive. I specialize in SMC pneumatic components

1. Switch form:

The smc solenoid valve is driven by the coil and can only be opened or closed. The switching time is short.

The drive of electric valve is generally driven by a motor. It takes a certain amount of time to complete the opening or closing action and can be adjusted.

2. Nature of work:

The solenoid valve generally has a small flow coefficient and a small working pressure difference. For example, a 25-port solenoid valve has a much smaller flow coefficient than a 15-port electric ball valve. The solenoid valve is driven by the electromagnetic coil, which is relatively easy to be damaged by voltage shock. Equivalent to the role of a switch, that is, on and off.

Electric valve is generally driven by a motor, which is more resistant to voltage shock. Solenoid valves are quick-opening and quick-closing. They are generally used in small flows and pressures, where electric switching is required where the switching frequency is high. The opening degree of the electric valve can be controlled, and the states are open, closed, half-open and half-closed. The flow rate of the medium in the pipeline can be controlled, but the solenoid valve cannot meet this requirement.

The solenoid valve can be reset when the power is off. The electric valve needs a reset device for this function.

3. Applicable technology:

The solenoid valve is suitable for some special process requirements, such as leakage, special fluid media, etc., and the price is more expensive.

Electric valves are generally used for regulation, and there are also switching values, such as the end of a fan coil.

As a kind of actuator of the automation instrument, the solenoid valve is used up sharply. This article analyzes the main characteristics of solenoid valves, and focuses on the perspective of application. A brief overview of the development of mature technologies in China is made in the direction of simplification, intelligence, generalization, and specialization. Make some discussions about social factors.

First, product selection points

1. The main control parameters of the solenoid valve are diameter, design nominal pressure, medium temperature range, and interface size.

2. Solenoid valve is used to open and close the valve with an electromagnet. It is usually used in two-position control with a diameter of less than 40mm. It is especially used to connect, cut off or switch the gas and liquid circuits.

3. The sealing performance of the valve is one of the main indicators for evaluating the quality of the valve. The sealing performance of the valve mainly includes two aspects, namely internal leakage and external leakage. End leakage

Development of SMC Solenoid Valve Simplified Direction

The simplest must be the simplest, and only the simple can last long. This is also the permanent pursuit of scientists and engineers. (1) Simplify the control circuit In the past, a large number of actuators used pneumatic and electric control circuits, which increased the complexity of the system. The pilot solenoid valve formed a control circuit using the working medium itself in the valve, and its structure was very simple. In the past, many technical parameters of solenoid valves at home and abroad were still limited. The diameter of domestic solenoid valves has been expanded to 30Omm; the temperature of the medium is as low as --200 and as high as 450 ; the working pressure is from vacuum to 25MPa. Action time is from ten seconds to several milliseconds. The new development of these technologies can completely replace the original two-volume control that is huge and expensive.

Development in the direction of intelligence: This mainly refers to how the solenoid valve can better cooperate with the intelligent instrument to improve the control accuracy and reliability of the system. It is generally believed that it is difficult to achieve very high precision in position adjustment, but in many cases, the appropriate method can be used to achieve the required high precision, which greatly saves costs.

(1) Double combination solenoid valve. This is a combination of different sized solenoid valves. The metering accuracy of the widely used dispensers is as high as 0.02%, and all use double solenoid valves. The large valve is opened, so that the refueling is nearly completed in a short time; then the large valve is closed, and the small valve is supplemented to ensure the flow accuracy. This technology has been used abroad for many years, and its products are manufactured by world famous solenoid valve professional companies. By the way, it is pointed out that the measurement of large flow in domestic oil depots is still introducing or imitating multi-stage shut-off valves with complicated structures and unstable performance in foreign countries. This product is not made by a world-renowned professional company because the market demand has not reached enough to attract their interest. In fact, our oil depot uses domestically produced large-flow dual combination valves, and the effect will be much better. The dual combination valve is also commonly used to control parameters such as temperature, pressure, and liquid level. The large valve guarantees the basic amount, and the small valve provides the compensation amount. In a system with relatively stable parameters, this position control can achieve quite high accuracy. For some systems with large parameter changes, the rate of change is still restricted to a certain extent. For example, temperature control systems are still affected by thermal inertia. Therefore, the proper use of the dual combination valve can meet the control requirements with respect to

1. The smc solenoid valve does not work after being energized. [1] Check whether the power wiring is bad rewire and connect the connector. Different types of solenoid valves (34 photos) check whether the power supply voltage is within the ± working range- adjust the normal position range coil Whether to de-solder re-solder the coil short-circuit whether the working pressure difference of the replacement coil is not suitable adjust the pressure difference or replace the proportional solenoid valve fluid temperature is too high replace the proportional solenoid valve has impurities that make the main valve core and moving iron of the solenoid valve The core is stuck clean, if the seal is damaged, replace the seal and install the filter. The liquid viscosity is too high, the frequency is too high and the life has expired Replace the product 2. The solenoid valve cannot close the main spool or the iron core seal Damage Replace the seal fluid temperature or viscosity is too high Replace the counterpart solenoid valve with impurities entering the solenoid valve core or moving iron core Perform cleaning spring life has expired or deformed Replace the throttle hole balance hole blocked Clean in time The working frequency is too high or the service life has expired change the product or update the product 3. In other cases, the internal leakage check whether the seal is damaged, whether the spring is badly assembled and the external leakage The connection is loose or the seal is broken Tighten the screws or replace the seal. There is noise when the power is turned on. The voltage fluctuation is not within the allowable range. Adjust the voltage. Impurities or unevenness on the iron core suction surface, clean or replace in time.