Today, Xiaobian will learn with you some taboos and solutions when installing Xi valves (above)

Taboo 1: The main materials, equipment and products used in construction lack technical quality appraisal documents or product certificates that meet the current standards issued by the state or the ministry.

Consequences: The quality of the project is unqualified, there are potential accidents, it cannot be delivered on time, and it must be reworked and repaired; As a result, the construction period is delayed, and the labor and material input increases.

Measures: The main materials, equipment and products used in water supply and drainage and heating and sanitation projects shall have technical quality appraisal documents or product certificates that meet the current standards issued by the state or the ministry; The product name, model, specification, national quality standard code, factory date, manufacturer name and location, factory product inspection certificate or code should be indicated.

Taboo 2: The necessary quality inspection is not carried out according to the regulations before the valve is installed.

Consequences: During the operation of the system, the valve switch is not flexible, the closure is not strict and the phenomenon of water leakage (steam) occurs, resulting in rework and repair, and even affecting the normal water supply (steam).

Measures: Before the valve is installed, the compressive strength and tightness test should be done. The test should be 10% of the quantity of each batch (same brand, same specification, same model), and not less than one. For the closed-circuit valves installed on the main pipe to play a shut-off role, the strength and tightness test should be carried out one by one. The strength and tightness test pressure of the valve shall comply with the provisions of the Code for Construction Quality Acceptance of Building Water Supply and Drainage and Heating Engineering (GB 50242-2002).

Taboo 3: 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; When the diameter of the water supply branch pipe is less than or equal to 50mm, the gate valve is used; The dry and riser pipes of hot water heating adopt shut-off valves; The suction pipe of the fire pump adopts a butterfly valve.

Consequence: Affect the normal opening and closing of the valve and adjust the resistance, pressure and other functions. Even caused the system to operate, the valve was damaged and had to be repaired.

Measures: Be familiar with the application range of various valves, and select the specifications and models of valves according to the requirements of the design. The nominal pressure of the valve should meet the requirements of the system test pressure. According to the requirements of the construction specification: the diameter of the water supply branch pipe is less than or equal to 50mm, and the shut-off valve should be used; When the pipe diameter is greater than 50mm, the gate valve should be used. Gate valves should be used for hot water heating dry and vertical control valves, and butterfly valves should not be used for fire pump suction pipes.

Taboo 4: Wrong valve installation method. For example, the flow direction of water (steam) of the globe 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 rod gate valve or butterfly valve has no opening and closing space, and the stem of the concealed valve is not facing the inspection door.

Consequences: Valve failure, difficult switch maintenance, and water leakage often caused by the valve stem facing down.

Measures: Install in strict accordance with the valve installation instructions, leave enough valve stem elongation opening height for open rod gate valve, fully consider the handle rotation space for butterfly valve, and various valve rods can not be lower than the horizontal position, let alone down. The concealed valve should not only be equipped with an inspection door that meets the needs of valve opening and closing, but also the valve stem should be facing the inspection door.

Taboo 5: Butterfly valve flange with ordinary valve flange.

Consequences: The size of the butterfly valve flange is different from that of the ordinary valve flange, and some of the flanges have a small inner diameter, while the butterfly valve disc is large, resulting in damage to the valve due to the inability to open or hard opening.

Measures: The flange should be machined according to the actual size of the butterfly valve flange.

Taboo 6: There are no reserved holes and embedded parts in the construction of the building structure, or the size of the reserved holes is too small and the embedded parts are not marked.

Consequences: During the construction of the heating and sanitation project, the building structure is chiseled, and even the stressed steel bar is cut off, which affects the safety performance of the building.

Measures: Carefully familiar with the construction drawings of the heating and sanitation project, according to the needs of the installation of pipelines and hangers, take the initiative to seriously cooperate with the reserved holes and embedded parts in the construction of the building structure, and refer to the design requirements and construction specifications.

Taboo 7: When the pipeline is welded, the wrong mouth of the pipe is not on a center line after the counterpart, the counterpart does not leave a gap, the thick-walled pipe does not shovel the groove, and the width and height of the weld do not meet the requirements of the construction specification.

Consequences: The misalignment of the pipe is not in the center line, which directly affects the welding quality and the appearance quality. There is no gap between the counterpart, the thick-walled pipe does not shovel the groove, and the width and height of the weld do not meet the requirements when the welding cannot meet the requirements of strength.

Measures: After welding the pipeline, the pipe can not be wrong, it should be on a center line, the gap should be left on the counterpart, the thick-walled pipe should be grooved, and the width and height of the weld should be welded in accordance with the requirements of the specification.