What types of cylinder control valves are there? How does the cylinder control valve work?

What types of cylinder control valves are there?


The solenoid head converts electrical energy into mechanical energy. It is composed of a static iron core, a coil, and a moving iron core (armature). It is divided into AC solenoid head and DC solenoid head according to the power supply used. According to the different structures, the cylinder control valve is divided into T-shaped and I-shaped solenoid heads. head:






T-shaped solenoid head
Suitable for AC armatures with large strokes. The armature is made of silicon steel sheets stacked into a T shape to prevent hysteresis eddy current losses and reduce iron consumption and heat generation.

I-shaped electromagnetic head
It is suitable for DC armatures (no hysteresis eddy current loss) and AC armatures with small strokes. The armature is a whole piece of ferromagnetic material.
· Because the suction force of the AC solenoid head changes at a frequency of 50Hz, the armature vibrates and makes a buzzing sound. A magnetic ring is set up on the suction surface of the armature to cause a time difference in the magnetic flux, reducing vibration and buzzing sound.


· There is no buzzing phenomenon in the DC solenoid head



The suction characteristics of AC solenoid heads and DC solenoid heads are similar
The smaller the stroke, the greater the suction power
Increase the voltage and the suction force becomes larger;decrease the voltage and the suction force becomes smaller.

· The starting current of the AC solenoid head is the largest
As the stroke of the moving iron core decreases, the current value becomes smaller, and the current value remains constant during pull-in (holding current)

· The current value of the DC solenoid head has nothing to do with the stroke and remains unchanged.
The electromagnetic head is continuously energized after being attracted, and usually will not burn out due to heat.
Impurities are stuck in the solenoid valve body (valve core, etc.), the solenoid head cannot be closed, the coil current is too large, and the heat is increased and burned out.
AC solenoid heads with high voltage and large stroke are more likely to burn out;AC solenoid heads with low voltage and small stroke are less likely to burn out.
DC solenoid coils generally do not burn out





Working principle of cylinder control valve


When the electromagnetic head coil is energized, it generates heat, and the temperature rises accordingly. When the heating and heat dissipation reach a balance, the coil temperature remains at a constant value (temperature rise value). The temperature rise value uses the resistance method to measure the internal temperature of the coil. JIS Z8704 Electrical measurement of temperature Method, use a thermometer to measure the surface temperature of the coil on site, which is about 20°C lower than the internal temperature. The allowable temperature rise depends on the insulation type of the coil. For cylinder control valves, the commonly used insulation types of solenoid heads are B or E. For special purposes, There are F types and H types for high temperature applications.





Insulation type Allowable temperature rise °C (JIS B8375) Maximum operating temperature °C (JIS C4003)
Category A Under 65 105
Type E Under 80 120
Type B below 90 130
F type below 115 155
H type below 140 180

Insulation resistance
JIS stipulates that a 500V insulation resistance meter is used to measure the resistance between the coil terminal and the ground. The insulation resistance value should be above 1MΩ.

Withstand voltage test
Between the coil terminal and the ground, apply 1500V sine wave of approximately 50 or 60Hz and test for 1 minute to see if the solenoid valve is damaged, cracked, or has external leakage. During mass production, use 1800V for 1 second.



Except for long-term continuous energization type products, the valve needs to be continuously energized for a long time (the energized time is longer than the non-energized time), so special attention is required.
When the double solenoid valve is operated by instantaneous energization, please ensure that the energization time is more than 0.1 seconds. Except for valves that must be supplied with oil, they can be used without oil lubrication due to pre-lubrication.
Valves that must be supplied with oil:
VP4□50, VP4□70, VP31□5, VPA4□50, VPA4□70, VPA31□5

When supplying oil and lubrication, 1# turbine oil (no additives) ISO VG32 should be used. The oil supply must be continued. Since the pre-added grease has been lost, stopping the oil supply midway will cause malfunction.