Analysis of the cause of leakage on the joint surface of the Ball Valve body

The Ball Valve consists of a main valve, a pilot valve, a relief valve, a joint and a conduit. It is a Universal Valve that relies on the discharge of the medium from the pilot valve to drive or control the main valve. The Ball Valve is an important accessory of the boiler, and is commonly installed on high-pressure power station boilers. Before installing the Ball Valve on the equipment, it is necessary to check whether the set pressure on the Universal Valve plate meets the system requirements, whether it has been calibrated, and whether the lead seals are intact. The Ball Valve must be installed vertically on the equipment or pipeline. The internal quality requirements of the Ball Valve are relatively high. Often due to factors such as internal materials, sealing surfaces, and bolt preload, after the Ball Valve is installed on the equipment, leakage is found on the joint surface of the valve body. Regarding this leakage topic, the following three major reasons and improvement methods are analyzed.

1. The flatness of the valve body joint surface is too poor or it is padded by hard impurities, causing sealing failure. For the leakage of the valve body joint surface caused by the poor flatness of the valve body joint surface, the method to eliminate it is to disassemble the Universal Valve and re-grind the joint surface until it meets the quality standards. If the seal fails due to impurities, the joint surface should be carefully cleaned during the assembly of the Universal Valve to prevent impurities from falling in.

2. The toothed seal gasket on the joint surface of the valve body does not meet the standards. For example, the toothed seal gasket has slight radial grooves, poor parallelism, and defects such as too sharp or too sloped teeth, which will cause the seal to fail. This will cause leakage on the joint surface of the valve body. During maintenance, the quality of spare parts should be strictly controlled, and the use of standard toothed seal gaskets can avoid this phenomenon.

3. The bolt tightening force on the joint surface is insufficient or biased, resulting in poor sealing of the joint surface. The elimination method is to adjust the bolt tightening force. When tightening the bolts, it must be tightened diagonally. It is best to measure the gaps at various locations while tightening, tighten the bolts until they can no longer be tightened, and make the gaps at various locations on the joint surface consistent.