How to choose high quality solenoid valve--Solenoid valve factory, solenoid valve introduction

Reliability and repeatability

When the instrument design engineer chooses the micro solenoid valve, it is often desirable that the solenoid valve can operate very reliably, especially to ensure long-term stability and repeatability. It is best to hope that there will be no running fluctuations and exceptions for a long time. It is often the first element in screening precision solenoid valves.

Solenoid valve and medium contact material

In particular, the design of the solenoid valve directly affects the reliability of the device itself. Therefore, when designing and using the sealing material of the solenoid valve, it is necessary to do more mathematical analysis for all the applied materials, not simply anti-corrosion and acid and alkali resistance.

Solenoid valves are in direct contact with sample reproducts, but most miniature isolation valves have an internal rubber material that can swell when exposed to sample reproducts. If you do not consider any design pre-compensation, then the rubber material will change the parameters and performance of the valve after a long time of use, and even affect the component to work properly, resulting in the problem that the entire instrument can not work.

Solenoid valve switching reaction time

The solenoid valve switch reaction time, which directly affects the authenticity of the mathematical analysis results of each group of experiments. Often this data is one of the most important parameter parameters that many engineers in the industry can easily ignore, and it is also one of the important indicators for distinguishing low-level solenoid valves from high-quality solenoid valves, because the solenoid valve switching reaction time has the coil, spring and internal structure of the solenoid valve. If it is determined by components, it is impossible to obtain accurate values without extensive application research experiments as the basis for design.

Ensure a longer service life

Continuous service life is the first parameter that solenoid valves should consider in most applications, especially in some applications where longer continuous service life is required. For example, in medical equipment and high-running instruments, the equipment requires continuous operation, requiring that the number of failures of the solenoid valve be minimal or even zero, even if it is used for a long time. Frequent maintenance and replacement of solenoid valves is best avoided. The continuous high service life also means that the components have better reliability in complex and varied applications.

In fact, the high reliability life guarantee is difficult to achieve. Experts with experience in solenoid valve design have mentioned that the most troublesome for high service life is the coil, spring, seal, that is, the design of the coil. Whenever the solenoid valve is working, the electromagnetic excitation will pull the plunger up, repeating several million times, which will cause the freewheeling of the coil and the heating of the coil in a short time. If the coil does not have the freewheeling function, the coil will burn. Bad, of course, if the temperature rise of the coil is too high, the coil will burn out. What is more important is that the temperature rise of the coil will conduct heat to the medium, causing distortion of the entire experimental data; the seal of the plunger is simultaneously with the end face of the passage. After the reciprocating motion, it will be worn out and leaks. This will happen in most valves. Some manufacturers solve it by replacing the spring or sealing material design, but the actual effect will not be too good.

Ensure that the design is lighter

Almost every improved instrument needs to be lighter, smaller, and more energy efficient than the original instrument, so each instrument design engineer needs to consider the size of each component at design time. In some precision, portable equipment, online monitoring equipment, it is especially necessary to reduce the volume of the solenoid valve. The reduction of the volume of the solenoid valve can better accommodate non-valve components such as circuit boards and container bottles. The compact valve body mechanism also reduces the inconvenience of carrying and transporting.

Ensure that the application’s traffic is met

As long as the instrument's compactness trend is maintained, every design engineer will need the same performance but smaller components. Increasing the flow rate is a critical parameter for miniature solenoid valves. However, parameters that affect the flow rate, such as energy consumption, pressure, and flow rate, are mutually constrained. The Cv (flow coefficient) value is related to the internal channel design of the valve itself. The flow coefficient can reflect the flow design level of the valve itself in one aspect. The Cv of each valve may be the same, but the volume is different; while the volume looks like a similar valve, but the Cv may be far apart.

When higher flow rates are required, the overall energy and pressure design must be within the user's requirements.

Experienced instrument design engineers know that even small flow increases can affect a variety of applications.

Aperture problems often increase the difficulty of valve selection.

Ensure more energy efficient devices

Energy saving is a very important factor for devices that are compact or portable with solenoid valves. A good miniature solenoid valve needs to optimize the use of electrical energy, while also reducing the weight of the valve body, making full use of the energy per ampere generated by the battery or power supply.

But in fact many products on the market are still very power-hungry. The control of the solenoid valve can be added to the PWM circuit to save energy in many cases. The switching power supply generally adopts pulse width modulation (PWM) technology, which is characterized by high frequency, high efficiency, high power density and high reliability. This type of circuit reduces the overall power but can also operate with a hold voltage, but the cost is higher. Valve design engineers are often concerned with finding low-energy, more efficient coils, which also require energy savings for the valve, which can increase the space on the instrument and the overall instrument performance.

Other selection reference factors:

First, applicability

Media characteristics

1. Different types of solenoid valves are selected for the gas, liquid or mixed state.

2, the medium temperature is different, the specification products also need to match, otherwise the coil will burn off, the seals will age, seriously affecting the life

3. The medium temperature should be selected within the allowable range of the solenoid valve.

Pipeline parameter

1. Select the valve port and model according to the medium flow direction requirement and pipe connection mode.

2. According to the flow rate and valve Kv value, the nominal diameter is selected.

3. The minimum working pressure difference is above 0.04Mpa, which is optional indirect pilot type; the minimum working pressure difference is close to or less than zero, you must use direct-acting or step-by-step direct-acting

Environmental conditions

1. The highest and lowest temperatures of the environment should be selected within the allowable range.

2. In the case of corrosive or explosive environment, corrosion resistance should be preferred according to safety requirements.

Power supply condition

1. According to the type of power supply, select AC and DC solenoid valves respectively.

2. Use the AC220V or DC24V as much as possible for the voltage specification.

  control precision

1. Ordinary solenoid valve can only open and close two positions. When the control precision is high and the parameter requirements are stable, please use multiple solenoid valves.

Second, reliability

  life span

This item is not included in the factory test project and is a type test project. In order to ensure quality, we should choose the famous brand products of regular manufacturers.

Working system

It is divided into long-term work system, repeated short-time work system and short-term work system.

  working frequency

When the operating frequency requirement is high, the structure should preferably be a direct-acting solenoid valve, and the power supply is preferably exchanged.

Operational reliability

Strictly speaking, this test has not been officially listed in China's professional standards for solenoid valves. In order to ensure quality, we should select the famous brand products of regular manufacturers. In some occasions, there are not many movements, but the reliability requirements are very high, such as fire protection, emergency protection, etc., should not be taken lightly. It is especially important to take two dual insurances.

Third, security

Corrosive medium

Plastic King solenoid valve and all stainless steel should be used; for strong corrosive media, isolation diaphragm must be used.

Explosive environment

The corresponding explosion-proof grade products must be selected. For outdoor installation or dusty occasions, waterproof and dustproof varieties should be used.

  Precautions

Economics is also a factor to consider, but compared to the three points above, economics is less important.

  to sum up

The choice of miniature solenoid valve needs to be measured according to the actual application conditions and the instrument itself. It needs to consider reliability, durability, shape, leakage, explosion safety, switching reaction time, weight and effective flow rate, low power consumption and professionalism under certain pressure. Match components and other factors. In all kinds of medium and high-end instruments, the solenoid valves that need to be used tend to be higher quality electronic components.