The DYFJ-C400 valve testing bench is the fourth generation pressure testing and detection equipment independently developed by Duojia Hydraulics on the basis of many years of production experience, in accordance with national standards and specifications.

The DYFJ-C400 valve test bench integrates mechanical and electrical systems, hydraulic systems, pressure testing, and storage and recycling of liquid mediums. It boasts comprehensive functions, stable performance, and high automation. It is widely used for leakage testing of sealing surfaces and shell strength (sands) on various high, medium, and low-pressure valves with nominal diameters of 200-400mm, in direct-connection flange designs. Test mediums include water, air, and oil.

The equipment is driven and controlled by hydraulic power and electrical systems, exerting no additional external forces on valves that could affect test results. This significantly enhances work efficiency and reduces labor intensity, making it an ideal new generation pressure testing and inspection equipment for valve manufacturing companies, users, and maintenance units.

DYFJ-C400 Type Valve Test Bench Working Principle and Structure

The DYFJ-C400 valve test bench operates by positioning the valve flange and clamping the back of the flange with movable claws, ensuring no external force affects the test results, thereby meeting the national standard requirements for valve testing.

The equipment is roughly divided into hydraulic pressure supply systems, electrical control systems, water circulation systems, and various operating devices.

The equipment features a diving double flip design, with each workbench equipped with a sealed blind plate. The left workbench is fitted with an in/out mechanism, directly driven by a hydraulic cylinder for even force distribution on the valve sealing surface and reliable clamping. Both left and right workbenches can be flipped 90 degrees, allowing the entire workbench surface to submerge into the external water tank. This enables the entire test valve to be fully immersed in water, facilitating the inspection of gas-tightness tests and observation of the valve sealing surface. It boasts good performance and a simple, compact structure.

Operation Instructions

1. Valve Mounting Method

Select a valve with a nominal diameter that matches the equipment model, turn on the power, and start the hydraulic system. Move the left carriage back to a position longer than the test valve. Radially move the clamping jaws to a size larger than the outer diameter of the test valve flange, and extend the clamping jaws axially to exceed the thickness of the valve flange. Place the valve flange face against the left workbench test blind plate, aligning with the center opening. Radially move the clamping jaws close to the valve flange, and axially move the clamping jaws to ensure the jaws are flush with the back of the valve flange. At this point, the valve should be securely clamped and held by the left-side clamping system to prevent it from falling off.

The sliding bracket moves to the right fixed workbench, the other end of the tested valve is tightly sealed against the right test blind flange, aligned with the central opening. Radially move the clamping jaws close to the valve flange. Axially move the clamping jaws to make them tightly adhere to the back of the valve flange. At this point, the valve should be securely held and fixed by the right-side clamping system, with the entire valve in a horizontal position.

2. Water Pressure Testing Methods (Bi-directional Inflow, Drainage)

After the valve bracket is installed, refer to the "Clamping Cylinder Pressure Comparison Table" to increase the hydraulic clamp's gripping force to the required pressure. Adjust the electrical contact pressure gauge (for a 25 kg valve, adjust the gauge needle to 2.5 MPa). Open the main water inlet, left and right water inlet valves, close the air inlet, drain water, and vent valves. Start the low-pressure water pump, observe the movement of the water pressure gauge needle. When the needle stops rising, it indicates that the valve cavity is full of water. Start the high-pressure water pump, and the pump will automatically stop when the water pressure reaches the set pressure on the electrical contact pressure gauge. The equipment then enters the water pressure maintenance state.

Upon reaching the pressure-holding time, the valve shows no issues. It should be first opened to release the water pressure inside the valve chamber, and then the valve can be removed.

3. Pressure Testing Methods (Bidirectional Intake, Venting)

The equipment does not come with its own gas source. The user must provide a separate gas source. Please consult the manufacturer before using high-pressure gases.

After the valve mounting is complete (for example, using compressed air, usually not exceeding 10 kg), open the water and air inlet valves, and close the water and air exhaust valves. Close the water and air inlet valves when the pressure gauge reaches the maximum pressure, and the equipment is in a pressure-holding state.

Upon reaching the pressure-holding time, the valve is free of any issues. It should first be opened to release the pressure inside the valve chamber before removing the valve.

Handling Precautions and Requirements

1. Align the equipment horizontally during installation or secure the base slot steel with concrete.

2. Use 46-grade anti-wear hydraulic oil (use anti-freeze 46-grade anti-wear hydraulic oil below 0℃), ensuring the oil level does not fall below the indicator. Regularly check the oil level and hydraulic oil. After one year of use, clean the oil tank and replace the hydraulic oil.

3. Add rust inhibitor to the recirculating water; replace the water promptly when the water quality deteriorates.

4. The equipment work surface should be kept clean, and there should be no debris between the test valve flange and the pressure test blank.

5. All moving parts of the test bench should be lubricated and kept clean for smooth operation.

6. Operators must undergo professional training before taking their posts, adhere to standardized procedures, and prioritize safety.