Application of Cartridge Valve in Hydraulic System

Application of Cartridge Valve in Hydraulic System

Cartridge valve is a general term for another type of hydraulic control valve. The basic core component is a two-way hydraulic resistance unit with a hydraulic control type and single control port installed in the main stage of the oil circuit (so it is also called a two-way cartridge valve). One or several plug-in components are combined in different ways and equipped with corresponding pilot control stages to form various control function units of the cartridge valve. Such as direction control function unit, pressure control unit, flow control unit, compound control function unit.

Cartridge valve has the following characteristics: small internal resistance, suitable for large flow work; most of the valve ports are sealed with cones, so the leakage is small, and it is also suitable for low-viscosity working media such as emulsions, simple structure, reliable work, and high degree of standardization; For large flow, high pressure, and more complex hydraulic systems, the size and weight can be significantly reduced. Its structure is as follows:

It is composed of three parts: insert element, control cover, and channel block. The insert element consists of a valve core, a valve sleeve, a spring and a seal; the control cover plate is equipped with corresponding pilot control level elements according to the different control functions of the cartridge valve; the channel block is the basis for inserting the insert element and installing the control cover plate The valve body is the connecting body of the main oil circuit and the control oil circuit. Among them, A and B are the main oil passages, and C is the control oil passage. The pressure and acting area of A, B, C ports are PA, PB, PC and A1, A2, A3 respectively, A3=A1+A2, Fs is the spring force.

Figure 2 is the hydraulic schematic diagram of the main cylinder part of the hydraulic system of the solid tire vulcanizing unit (partial system schematic diagram, incomplete schematic diagram).

It can be seen from the figure that this system is all controlled by cartridge valves, which require different hydraulic valves. According to the characteristics of the machine itself and the main technical parameters: the upward speed of the cylinder is required to reach 20mm/s, the downward speed to reach 25mm/s, the cylinder diameter/rod diameter Φ600mm/Φ540mm, the flow rate Q=A*V can be used to obtain the oil cylinder into the oil cavity. The flow rate is 339L/min, and the required flow rate is relatively large. Moreover, the main engine system has higher requirements for mechanical motion sensitivity and the hydraulic system has strict requirements on sealing. Therefore, the cartridge valve is selected as the oil circuit control element due to comprehensive consideration.

 

Two-way cartridge valve constitutes various combination valves

1 Cartridge valve constitutes a pressure control valve

According to the working principle of the cartridge valve, when PAA1+PBA2>PCA3+FS, the spool opens and the oil circuits A and B are connected. As shown in Figure 2, the cartridge valve C14, when the solenoid valve YV9 is energized, the C port of C14 is directly connected to the oil tank, and the C port pressure is zero. It can be seen that the oil circuits A and B are connected. When the pressure of the A port is greater than the spring force, the system pressure oil returns to the oil tank, so this cartridge valve acts as a relief valve to control the oil port pressure of the cylinder diameter.

Look at the following example, the cartridge valve in Figure 3 is used as a relief valve.

The B port of the cartridge valve C8 is directly connected to the oil tank, and the C port is connected to the overflow valve. The pressure of both is zero. It can be seen that when the pressure of the A port is greater than the spring force, the oil circuits A and B are connected, and the pressure oil passes through B port returns to the oil tank, at this time the cartridge valve acts as an overflow valve to control the system pressure.

2 Cartridge valve constitutes direction control

Looking at Figure 2 again, it can be seen from the hydraulic action schedule that the solenoid valves YV7A and YV7B are energized at the same time to control the upward movement of the main cylinder. When the two are energized at the same time, the C port of the cartridge valve C11 and C13 is connected to the oil tank, and when PA>FS, the A and B ports are directly connected, and the oil can flow from A to B; when only YV7B is energized, the main cylinder Downward movement. Among them, the PA of C13 is less than PB, the valve core is opened, and the oil can flow from B to A. In these two places, the cartridge valve functions as a one-way valve.

Look at another picture, Figure 4 two-position three-way valve.

This cartridge valve is used as a two-position two-way valve. When the two-position three-way solenoid valve is de-energized, the spool is opened, and A and B are connected; when the solenoid valve is energized, the spool is closed, and A and B are blocked.

3 Cartridge valve constitutes flow control valve

It can be seen from C14 in Figure 2 that there is a spool raising limit device on the top cover of the valve. By adjusting the position of the limit device, the size of the flow section of the valve port can be adjusted, thereby adjusting the flow rate. By adjusting the flow rate, the downward speed of the main cylinder can be adjusted. This cartridge valve serves as a throttle valve.

summary

Through more complex combinations, more hydraulic valve functions can be achieved. Through the combination, the cartridge valve can be used as a pressure control valve (sequence valve, pressure reducing valve), flow control valve (one-way throttle valve, throttle valve), directional control valve (speed control valve, hydraulic control one-way valve, two Two-way reversing valve, etc.) and compound valve.

At present, the cartridge valve has the following series: K series cartridge valve, L series cartridge valve, TJ series cartridge valve, Z series cartridge valve. Several series models are different, and manufacturers can design and manufacture integrated channel blocks according to user requirements. Cartridge valves are widely used in hydraulic systems according to their own characteristics.