The DYFJ-A400 type valve testing bench is a fourth-generation pressure testing and inspection device independently developed by Duojia Hydraulics on the basis of many years of production experience, in accordance with national standard specifications.

The DYFJ-A400 valve testing bench integrates mechanical, hydraulic systems, pressure testing, and the storage and recycling of liquid mediums. It features comprehensive functions, stable performance, and high automation. It is widely used for sealing surface leakage tests and shell strength (pinhole) tests on various high, medium, and low-pressure valves with nominal diameters of 200-400mm, in the form of straight-through flanges. Test mediums: water, gas, oil.

The equipment is fully powered by hydraulic drive and electric control, with no external force affecting the valve test results, significantly enhancing work efficiency and reducing labor intensity. It is an ideal new pressure testing and inspection equipment for valve manufacturing companies, users, and maintenance units.

DYFJ-A400 Type Valve Test Bench Working Principle and Structure

The DYFJ-A400 valve test bench operates by positioning the valve flange and clamping the back of the flange with movable claws, ensuring no external forces that could affect the test results. It meets the national standard requirements for valve testing.

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

The equipment features a horizontal clamping design with each side of the workbench equipped with a sealed blind plate. The left workbench is fitted with an in/out mechanism directly driven by a hydraulic cylinder, ensuring even force distribution on the valve sealing surface and reliable tightness. (Left) The right workbench can be flipped 90 degrees for easy inspection of gas-tightness tests and observation of the valve sealing surface, boasting good performance and a simple, compact structure.

Operation Instructions

Valve Mounting Method

Select a valve with a nominal bore size that matches the equipment model, turn on the power, and start the hydraulic system. Move the left-hand carriage back to a position longer than the valve being tested. Radially move the adjustable clamp to exceed the outer diameter of the valve flange. Extend the clamp axially to exceed the thickness of the valve flange. Place the valve flange face tightly against the left-hand workbench test blind plate, aligning with the center opening. Radially move the clamp close to the valve flange, and axially move the clamp to ensure it is tightly against the back of the valve flange. At this point, the valve should be securely held and fixed by the left-hand clamping system, ensuring the valve does not come loose.

The left-hand moving bracket advances to the right-hand fixed workbench, the other end of the valve being tightly pressed against the right-hand pressure test blank flange, aligned with the center empty space. Radially move the clamping jaws close to the valve flange; axially move the clamping jaws to make the jaws tightly adhere to the back of the valve flange. At this point, the valve should be securely clamped and fixed by the right-hand clamping system, with the valve in an overall horizontal position.

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

After the valve clamp is installed, refer to the "Clamping Cylinder Pressure Chart" 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 pointer to 2.5 MPa). Open the main water inlet, left and right water inlet valves, close the air inlet, drain, and vent valves. Start the low-pressure water pump, observe the movement of the water pressure gauge pointer. When the pointer stops rising, it indicates that the valve cavity is fully filled with water. Start the high-pressure water pump; 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 is free of any issues. First, open the water valve to relieve the pressure inside the valve chamber, and then remove the valve.

3. Pressure Testing Methods (Bi-directional Intake and Exhaust)

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

After the valve fixture is completed (for example, using pressurized air, generally not exceeding 10 kg), open the inlet and air inlet valves, and close the drain and air release valves. Close the inlet 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, there should be no issues with the valve. First, open the vent valve to release the pressure inside the valve chamber, and then remove the valve.

Handling Instructions and Requirements

Ensure the equipment is level during installation or secure the base channel steel with concrete.

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

3. Add rust prevention powder to the recirculating water, and change the water promptly when the water quality deteriorates.

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

5. Add lubricant to all moving parts of the test bench to ensure clean and smooth operation.

6. Operators must undergo professional training before assuming their positions, adhere to standard procedures, and prioritize safety.