밸브는 화학 기업에서 가장 일반적인 장비입니다. 밸브 설치는 쉬워 보이지만, 관련 기술기준에 맞지 않게 설치하면 안전사고로 이어질 수 있습니다. 오늘은 밸브 설치에 관한 경험과 지식을 여러분과 공유하고 싶습니다.

I. 동절기 공사 중 음수온도에서 수압시험을 실시한다.

• 결과: 수압시험 중 배관 내부의 급속한 동결로 인해 배관이 동결되어 손상됩니다.
• 조치: 겨울 공사 전에 수압 테스트를 실시하고 테스트 후 물을 불어내십시오. 특히 밸브 내부의 물을 완전히 제거해야 합니다. 그렇지 않으면 밸브가 녹슬거나 얼거나 갈라질 수 있습니다. 겨울철 수압 테스트를 실시할 경우 실내 온도가 양호한 상태에서 프로젝트를 수행해야 하며 테스트 후에는 물을 불어내야 합니다.

II. 파이프라인 시스템은 완료되기 전에 주의 깊게 세척되지 않으며 흐름과 속도가 파이프라인 세척 요구 사항을 충족할 수 없습니다.

• 결과: 수질은 파이프라인 시스템의 운영 요구 사항을 충족할 수 없으며 종종 파이프라인 단면이 줄어들거나 막히는 결과를 낳습니다.
• 조치: 세척은 시스템의 최대 설계 유량 또는 3m/s 이상의 물 유량으로 수행되어야 합니다. 배출구의 물색과 투명도가 유입구의 물색과 투명도와 시각적으로 일치하는 경우 자격을 갖춘 것으로 간주됩니다.

III. 하수관, 빗물관, 응축관 등은 폐쇄수검사를 거치지 않고 숨겨집니다.

• 결과: 누수로 인해 사용자에게 손실이 발생할 수 있습니다.
• 조치: 폐쇄수역 시험작업은 사양에 따라 엄격하게 검사하고 승인해야 합니다. 지하 매설물, 천정, 배관 사이에 하수관, 빗물관, 응축관 등을 은폐 설치하여 누수가 없도록 하여야 한다.

IV 파이프라인 시스템의 수압 강도 테스트 및 기밀 테스트 중 누출 검사가 충분하지 않습니다.

• 결과: 파이프라인 시스템이 실행된 후에 누출이 발생하여 정상적인 사용에 영향을 미칩니다.
• 조치: 설계 요구 사항 및 건설 사양에 따라 파이프라인 시스템을 테스트할 때 지정된 시간 내에 압력 값이나 수위 변화를 기록하는 것 외에도 누출 문제를 주의 깊게 확인하는 것이 특히 중요합니다.

V. 버터 플라이 밸브의 플랜지 플레이트는 일반 밸브 플랜지 플레이트로 만들어집니다.

• 결과: 버터플라이 밸브와 일반 밸브의 플랜지 플레이트 치수가 다릅니다. 일부 플랜지는 내경이 작은 반면, 버터플라이 밸브의 디스크는 크기 때문에 열리지 않거나 강제로 열려 밸브가 손상될 수 있습니다.
• Measures: The flange plate should be processed according to the actual size of the butterfly valve flange.

VI. The valve installation method is incorrect.

For example, the water (steam) flow direction of the stop valve or check valve is opposite to the mark, the valve stem is installed downward, the horizontally installed check valve is installed vertically, the handle of the open-stem gate valve or butterfly valve has no space for opening and closing, and the valve stem of the concealed valve does not face the inspection door.

• Consequences: Valve malfunction, difficulty in switch maintenance, and often water leakage caused by the valve stem pointing downwards.
• Measures: Install the valve strictly according to the installation instructions. For the rising stem gate valve, leave enough space for the valve stem to extend and open. For the butterfly valve, fully consider the space for rotating the handle. The valve stem should not be lower than the horizontal position, and it should not be downward. For concealed valves, not only should there be an inspection door that meets the needs of opening and closing the valve, but also the valve stem should face the inspection door.

VII. The specifications and models of the installed valves do not meet the design requirements.

For example, the nominal pressure of the valve is less than the system test pressure; gate valves are used for water supply branch pipes with diameters less than or equal to 50mm; stop valves are used for hot water heating dry and vertical pipes; and butterfly valves are used for fire pump suction pipes.

• Consequences: It affects the normal opening and closing of the valve and the adjustment of resistance and pressure. It may even cause damage to the valve during system operation and necessitate repairs.
• Measures: Familiarize yourself with the application scope of various valves, and select the specifications and models of valves according to the design requirements. The nominal pressure of the valve should meet the requirements of the system test pressure. According to the construction specifications, when the diameter of the water supply branch pipe is less than or equal to 50mm, a globe valve should be used; when the diameter is greater than 50mm, a gate valve should be used. The hot water heating dry and riser pipes should use gate valves, and the suction pipe of the fire pump should not use butterfly valves.

VIII. The necessary quality inspection is not conducted according to the regulations before the installation of the valve.

• Consequences: The valve switch is not flexible during system operation, resulting in poor closure and leakage (steam) phenomena, causing rework and repair, and even affecting normal water (steam) supply.
• Measures: Before the installation of valves, pressure strength and tightness tests should be conducted. The tests should be conducted on 10% of each batch (of the same brand, same specification, and same model) and no less than one. For closed-circuit valves installed on the main pipe to cut off, strength and tightness tests should be conducted one by one. The pressure for valve strength and tightness tests should comply with the provisions of the Code for Acceptance of Construction Quality of Water Supply Drainage and Heating Works (GB 50242-2002).

IX. Improper installation of valves in high temperature environment.

• Consequence: leakage accident
• Measures: For high temperature valves over 200℃, they are at normal temperature during installation, but after normal use, the temperature rises, the bolts expand due to heating, and the gap increases, so they must be tightened again, which is called "hot tightening". Operators should pay attention to this work, otherwise leakage is likely to occur.

X. Valve flip-chip

• Consequences: Valves such as stop valves, throttle valves, pressure reducing valves, and check valves all have directionality. If installed upside down, the throttle valve will affect the effectiveness and lifespan of the valve; the pressure reducing valve will not work at all, and the check valve may even pose a danger.
• Measures: General valves have directional signs on the valve body; if not, they should be correctly identified based on the working principle of the valve. The valve cavity of the globe valve is asymmetric left and right, and the fluid should be allowed to pass through the valve port from bottom to top, which reduces fluid resistance (determined by shape) and saves effort when opening (due to the upward pressure of the medium). After closing, the medium does not press on the packing, which is convenient for maintenance. This is why the globe valve cannot be installed backwards. Gate valves should not be installed upside down (i.e., with the handwheel facing down), otherwise the medium will remain in the valve cover space for a long time, which can easily corrode the valve stem and is also prohibited for certain process requirements. At the same time, it is extremely inconvenient to replace the packing. For rising stem gate valves, do not install them underground, otherwise the exposed valve stem will be corroded due to moisture. For lift check valves, ensure that their valve discs are vertical during installation to facilitate flexible lifting. For swing check valves, ensure that their pin shafts are horizontal during installation to facilitate flexible swinging. Pressure reducing valves should be installed upright on horizontal pipelines, and should not be tilted in any direction.