Valve knowledge: Valve testing, installation, and common faults

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Testing, installation of valves and common faults – Testing and adjustment: 1. All components of this product, whether manual, pneumatic, hydraulic, or electric, are carefully adjusted before leaving the factory. When checking the sealing performance, the user should connect the components according to the connection method shown in Figure 1 and follow the direction indicated by the flow arrows; the inlet and outlet sides should be securely fixed. The disc valve should then be closed, pressure applied to the inlet side, and any leaks checked at the outlet side. Before conducting strength tests on the pipeline, the disc should be opened to prevent damage to the sealing surfaces. http://www.fspv.com/imge/shi_2.gif2. Although our products undergo strict inspection and testing before leaving the factory, there are still individual cases where the screws shift during transportation, requiring re-adjustment using pneumatic or hydraulic methods; please refer to the instructions for the accompanying drive units. 3. The (electric actuated disc valve) has its control mechanism’s opening and closing stroke adjusted at the time of leaving the factory. To prevent the wrong direction when powering on, after turning on the power for the first time, the user should first move the manual control to the half-open position, and then press the electric switch to verify that the direction indicated on the dial matches the direction in which the valve opens and closes. Common faults and solutions: 1. Before installation, verify that the performance of the product manufactured by our factory as well as the direction indicated by the flow arrows match the operating conditions. Clean the interior of the valve thoroughly; it is not allowed for any impurities or foreign objects to remain on the seal rings and the butterfly disc. The butterfly disc must not be closed until the interior has been cleaned, to avoid damaging the seal rings. 2. It is recommended to use flanges specifically designed for disc valves for the installation of disc plates, namely the HGJ54-91 type socket-welded steel flanges, as shown in Figure 3. 3. Regarding the position of installation within the pipeline, the optimal option is vertical installation; however, inverted installation is not allowed. 4. Flow rate needs to be adjusted during use, controlled by a worm gear box. 5. For butterfly valves that are opened and closed frequently, the worm gear box cover should be opened every about two months to check whether the grease is in good condition; an appropriate amount of grease should be maintained. 6. Check that all connection points are properly tightened, which ensures the compactness of the packing and also guarantees smooth rotation of the valve stem. 7. Metal-sealed butterfly valve products are not suitable for installation at the end of a pipeline. If installation at the pipeline end is necessary, an outlet flange must be used to prevent the sealing ring from being compressed or displaced. 8. During the installation and use of the valve stem, it is necessary to regularly check the performance of the valve and address any faults that arise promptly. 9. Possible faults and their remediation methods:
Seal surface leakage:
1. Debris trapped between the butterfly plate and the seal surface.
2. The butterfly plate and the seal surface are not aligned properly when closed.
3. Uneven force on the flange bolts on the outlet side, or they are not installed as specified in Figure 1.
4. Pressure application is not carried out in accordance with the requirements of Figure 1.
Remediation:
1. Remove debris and clean the interior of the valve.
2. Adjust the adjustment screws of the worm gear or electric actuator to ensure the valve closes in the correct position.
3. Check the flat surfaces of the flanges and ensure that the bolts apply even pressure.
4. Apply pressure in the direction indicated by the seal.

Leakage at both ends of the valve:
1. The sealing gaskets on both sides are damaged.
2. The flanges are not tightened evenly or not tightened at all.
3. The upper and lower sealing gaskets of the seal ring are damaged.
Remediation:
1. Replace the sealing gaskets.
2. Tighten the flange bolts evenly.
3. Remove the retaining rings from the valve, replace the seal ring, and replace any damaged gaskets