Views: 0 Author: Site Editor Publish Time: 2025-12-19 Origin: Site
There are significant differences in functions, structures, application scenarios and installation methods between superimposed hydraulically controlled check valves and hydraulic locks. The specific differences are as follows:
1. Function positioning
Superimposed hydraulic controlled check valve
Core function: Adding a hydraulic control function to the one-way valve, allowing oil to flow freely in the forward direction, and in the reverse direction, it can be actively opened through external control of oil pressure to achieve two-way flow.
Additional features:
Hydraulic cylinder support: prevent the vertical hydraulic cylinder from sliding down due to slide valve leakage.
Pressure maintenance: The tightness of the poppet valve is used to maintain pressure for a long time and make up for the gap leakage problem of the slide valve type reversing valve.
Locking: When the reversing valve is in the neutral position, the hydraulic cylinder oil is sealed in both directions to prevent external force from moving the piston.
Large flow oil discharge: When the hydraulic cylinder retreats, the oil pressure is controlled to open the hydraulic control check valve to avoid the throttling restriction of the small flow slide valve.
Oil filling: When the vertical hydraulic cylinder descends at high speed, it acts as an oil filling valve to replenish oil to prevent air suction and negative pressure.
Combined reversing: Two hydraulically controlled one-way valves are connected in parallel with the one-way valve to simulate the function of a three-position three-way reversing valve.
hydraulic lock
Core function: Through the combination of two-way hydraulic control check valves, the hydraulic circuit can be locked in two directions to prevent the actuator (such as a hydraulic cylinder) from unexpected movement due to the weight of the load or external force (such as a 'falling leg' or 'soft leg' of a crane leg).
Additional features:
Interlock: When the slide valve is in the neutral position, the two-way hydraulic cylinder is stationary; when the slide valve changes direction, the corresponding one-way valve is opened by controlling the oil circuit to achieve oil circuit connectivity.
Safety protection: In the load-bearing hydraulic system, the one-way valve is forced to open to connect the oil circuit, and remains locked when the oil supply is stopped.
2. Structural composition
Superimposed hydraulic controlled check valve
Structural features: Adopting a superimposed design, it can be directly superimposed on the hydraulic valve block or other valves, with high integration and space saving.
Key components:
Valve body: There is an oil passage inside with mounting holes for superimposed installation.
Port A, Port B: the working oil port connecting the actuator (cylinder or motor).
Control oil port (X/Y): Introduce control pressure oil to achieve reverse opening.
Oil drain port (L): Specially designed for external leakage, it leads the leakage oil from the control piston cavity back to the oil tank to prevent back pressure from affecting the opening.
Valve core: poppet valve core or slide valve core, realizing one-way function.
Spring: Provides preload force to keep the valve core closed when there is no control pressure.
Control piston: Under the action of control oil pressure, the valve core is pushed to open.
hydraulic lock
Structural features: It is composed of two hydraulically controlled one-way valves. It uses each other's oil line pressure as the pilot control oil to achieve two-way locking.
Key components:
Shared valve body: integrated with two hydraulically controlled one-way valves.
Control piston: similar to the superimposed hydraulic control check valve, but needs to coordinate the actions of the two valve cores.
Poppet valve core: The two poppet valve cores respectively control the two-way oil circuit. When pressure oil is introduced into any oil inlet, the two valves can be opened at the same time to achieve two-way communication.
III. Application scenarios
Superimposed hydraulic controlled check valve
Typical applications:
Engineering machinery: crane leg cylinders, excavator arm/bucket cylinders, loader arm cylinders.
Injection molding machine: clamping cylinder maintains pressure.
Press: the main cylinder maintains pressure.
Metallurgical equipment: rolling mill reduction device.
Ship deck machinery: winches, cranes.
General scenario: Any situation where it is necessary to prevent the cylinder from sliding down due to the weight of the load or the motor from reversing.
hydraulic lock
Typical applications:
Crane outrigger locking oil circuit: prevent vertical outrigger hydraulic cylinder from 'falling off' or 'soft leg'.
Telescopic cylinder of tunnel boring machine: keeps the actuator stationary in the load-bearing hydraulic system.
Reversal control of tilting plow cylinder motion: Precise control is achieved through two-way locking.
Truck-mounted crane hydraulic system: prevents the load from sliding down and improves safety.
4. Installation method
Superimposed hydraulic controlled check valve
Installation features: It is installed on the working oil port of the directional control valve (such as a reversing valve) in the form of a superimposed plate, without the need for separate pipeline connections. It has high integration and facilitates system design and installation.
hydraulic lock
Installation characteristics: Usually installed in the hydraulic system as an independent component, it needs to connect the two-way oil circuit and the control oil circuit. The installation flexibility is low, but the function is highly targeted.
