Solenoid valve selection guide

Before choosing a type of solenoid valve, sufficient information about the application must be gathered. This guide describes the key parameters for solenoid valves.

Important Information

These are the most important guidelines when selecting a solenoid valve. Keep these guidelines in mind before choosing a valve.

• Solenoid valves are very sensitive to dirt and only work with clean liquids or air.

• Note that indirectly controlled solenoid valves require a permanent pressure differential of around 0.5 bar to function properly. Therefore, you can not use indirect operated valves in a closed circuit or systems with a low inlet pressure. Direct and semi-direct operated valves operate with a pressure differential from 0 bar.

• Make sure that the used medium and temperature are compatible with the materials of the valve, such as body and the seal materials.

• Solenoid valves open and close fast (between around 10 and 1000 ms). Improper use can cause pressure transients in the system (water hammer).

Principle of operation

There are different types of solenoid valves, each with different principles of operation:

• Direct operated (operating from 0 bar)

• Semi-direct operated (operating from 0 bar)

• Indirect operated (pressure differential required, normally at least 0.5 bar)

It is important to choose the right operation principle. Direct operated valves operate from 0 bar. In the valve there is a small orifice which is sealed off by a plunger with a polymer gasket. If the solenoid (electromagnet) is electrically energized, the plunger is lifted by the electromagnetic force and the valve opens. This principle is often used for small valves and is suitable for small flow rates. For larger flow rates, a semi-direct or indirect operated valve is recommended. Both make use of the medium pressure to open and close the valve. Semi-direct operated valves operate from 0 bar and often have a more powerful coil than indirect operated valves. Indirect operated valves need a permanent pressure differential of around 0.5 bar for proper operation. The advantage of indirectly operated valves is that they usually can control large flows with a relatively small coil and thereby have a reduced energy consumption.

Check if there is a permanent pressure differential over the valve of at least 0.5 bar. In this is the case, an indirect operated valve may be chosen (a semi-direct valve is of course also allowed in this case). If this is not the case (low inlet pressure, closed circuit, ..), choose a (semi-)direct operated solenoid valve.

from Internet

In order to further implement the security work and improve the emergency handling capacity of the company’s production staff, At  4 PM on May 21, BLCH Pneumatic Technology Co., Ltd. carried out fire emergency drill and training, and invited Yueqing Antong Safety Technology Service Co., Ltd. to participate in the on-site guidance.

Urgent notice: “the company first floor waste warehouse fire!”As the fire control room alarm sounded, the fire drill officially began.

The security team quickly closed the fire surrounding, and call 119 for support; The evacuation team guided the personnel to immediately implement the fire fighting, and finally the fire was under control, and the on-site personnel  were transferred in time. During the exercise, each teams responded positively, their responsibilities were clear, and the exercise procedure was well organized and orderly.

After the fire drill, we organized to learn the early fire fighting knowledge evacuation and escape knowledge and fire extinguishers and other fire equipment  correct operation method on the site.

The fire emergency exercise fully enhanced the awareness of fire safety of all the staff of the company, strengthened the knowledge of fire safety and the actual combat skills of the correct use of equipment.

Select the correct cylinder according to the following conditions:

1. According to the type of cylinder:

Choose the type of cylinder according to the working requirements and conditions.  Use a heat-resistant cylinder in a high temperature environment.  In a corrosive environment, the use of corrosion – resistant cylinder.  Install a dust cover on the protruding end of the piston rod in harsh environments such as dust.  When no pollution is required, the cylinder without oil or oil lubrication should be selected.

2, according to the size of the force:

According to the size of the load force to determine the cylinder output thrust and tension.  In general, the acting force of the cylinder required by the theoretical equilibrium condition of uniform external load is multiplied by the coefficient 1.5~2.0, so that the output force of the cylinder is slightly surplus.  The cylinder diameter is too small, the output force is not enough, but the cylinder diameter is too large, so that the equipment is cumbersome, the cost increases, and increases the consumption of gas, waste energy.  In the fixture design, should try to use the expansion mechanism, in order to reduce the cylinder size.

3. According to the stroke of the piston:

And the use of the occasion and the stroke of the mechanism, but generally do not choose full stroke, to prevent the piston and cylinder head collision.  If used for clamping machine structure, it should increase the allowance of 10~20mm according to the calculation required stroke.  It should be selected as standard trip as far as possible to ensure the supply speed and reduce the cost.

4. According to the movement speed of the piston:

Mainly depends on the cylinder input compressed air flow, cylinder inlet and exhaust port size and pipe diameter.  High speed motion is required.  The cylinder movement speed is generally 50~1000mm/s.  For high-speed motion of the cylinder, the intake pipe of large internal passage should be selected;  For the load changes, in order to get slow and steady speed, can choose with throttle device or gas-liquid damping cylinder, it is easier to achieve speed control.  When selecting throttle valve to control the cylinder speed, note that: when the horizontally installed cylinder pushes the load, it is recommended to use exhaust throttle speed regulation;  When vertically installed cylinders lift loads, it is recommended to use intake throttle speed regulation;  When the stroke is required to move smoothly to avoid impact, the cylinder with buffer device should be selected.