As the most common and easiest to understand hydraulic valve in the hydraulic industry, the hydraulic check valve is widely used in hydraulic systems and occupies a vital position. It is a mature component in hydraulic systems. However, even so, it still has some problems in certain specific application scenarios, especially in the application of tightened able check valves in aluminum valve blocks, there is still room for optimization and improvement.
Traditional screw-in check valves have some problems in some applications with relatively high requirements as follows:
1. Occasionally, cartridge valves may loosen and fall off the valve block on their own.
This is mainly due to a combination of vibration and different temperatures and expansion coefficients between the cartridge valve and the valve block, which weakens the screw connection. In applications with structural loads, deformation of the hydraulic valve block may cause the screw connection to unscrew itself during operation. Since hydraulic check valves use axial preload seals, even a slight unscrewing can lead to a loss or weakening of the seal, which in turn has serious consequences for the hydraulic system and application.
2. There have been failures related to seal damage
Especially with the lower Shore hardness O-rings commonly used in low-temperature applications. The complex installation position at the bottom of the hole plus the torque required to preload the O-ring poses some risks. In some cases, the O-ring will be cut off during installation, as shown in the following figure:
3. Contamination of aluminum block internal thread fragments
Solid matter contamination in hydraulic oil is a common cause of hydraulic failures and machine downtime during commissioning and continuous operation. Wearing in the form of aluminum block internal thread fragments is a serious challenge when using steel threaded valves with aluminum valve blocks. In addition to causing damage to seals, valves and other system components, thread fragments may also block the check valve, resulting in the screw-in torque being reached before the required screw-in depth of the valve is reached. Therefore, during commissioning, a complex flushing process is usually required to remove the debris from the system.
A company called WEBER-HYDRAULIK has developed a completely new form of RVH series non-return valve, as shown in the figure below. The RVH series valve has a radial seal and is fixed in the valve hole by a round wire clamp ring. Due to the preload of the clamp ring and the action of the valve contact surface and the clamp ring, the force on the clamp ring is decomposed into the material of the valve block at a 45° angle. In the aluminum block burst test, the valve can withstand a pressure of more than 1000 bar. The RVH series valve adopts a prefabricated structure design with a conical spring contained in the retainer.
Three sizes of check valves: maximum diameter 10mm/14mm/22mm. 20/50/120 L/min
① Despite its compact design, the valve still achieves a large opening stroke;
②The pressure drop generated is lower than that of similar valves with traditional designs, which can save energy for the system;
③Since the weight of the moving parts is relatively light, soft springs can be used, allowing extremely low opening pressure;
④Due to the relatively low mass of the sealing plate, the valve’s ability to resist shock and vibration is significantly enhanced.
Due to these characteristics, the RVH series valve is particularly suitable for challenging applications, low temperature applications, applications with high vibration and shock loads and structural loads, and systems with high energy requirements. In addition to a wide range of application possibilities, this valve is easy to install compared to traditional screw-in check valves, so a lot of time can be saved during installation. Customers do not need to machine threads in the valve block, and there is no need to tighten the bolts, which also reduces the possibility of possible thread debris contamination when screwing in.