1. Hydrstatic test at negative temperature during construction in winter.
Consequences: because the tube freezes quickly during the hydraulic test, the tube is frozen.
Measures: try to carry out hydraulic test before winter application, and after the pressure test to blow the water, especially the water in the valve must be removed in the net, otherwise the valve is light rust, heavy frozen crack. The project must be carried out in winter, under the indoor positive temperature, and the water should be blown clean after the pressure test.
2. The valve installation method is wrong.
For example, the check valve flow direction is opposite to the mark, the stem is installed down, the horizontally installed check valve is installed vertically, there is no open or closed space, and the stem of the hidden valve is not facing the inspection door.
Consequences: the valve failure, the switch maintenance is difficult, and the valve shaft facing down often causes water leakage.
Measures: strictly according to the valve installation instructions for installation, open rod gate valve to keep the valve stem elongation opening height, butterfly valve fully consider the handle rotation space, all kinds of valve rod can not be below the horizontal position, let alone down. The concealed valve should not only set the inspection door to meet the opening and closing of the valve, but the valve stem should be facing the inspection door.
3. The specifications and models of the installed valve do not meet the design requirements.
For example, the nominal pressure of the valve is less than the system test pressure; the gate valve for the feed water branch pipe when the pipe diameter is less than or equal to 50mm; the dry and risers for hot water heating; and the fire pump suction pipe adopts butterfly valve.
Consequences: affect the normal opening and closing of the valve and adjust the resistance, pressure and other functions. Even cause the system operation, the valve damage is forced to repair.
Measures: Be familiar 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 shall meet the requirements of the system test pressure. According to the construction code: stop valve shall be used when the pipe diameter is less than or equal to 50mm; gate valve shall be used when the pipe diameter is greater than 50mm. Hot water heating dry, vertical control valve should be used gate valve, fire water pump suction pipe should not use butterfly valve.
4. Improper installation of valves in high temperature environment.
Consequences: cause a leakage accident
Measures: the high temperature valve above 200℃, because the installation is at normal temperature, and after normal use, the temperature rises, the bolt is heat expansion, the gap is increased, so it must be tightened again, called “hot tight”, operators should pay attention to this work, otherwise it is easy to leak.
Tianjin Tanggu Water Seal Valve Co., Ltd. is a technologically advanced elastic seat valve supporting enterprises, the products are elastic seat wafer butterfly valve, lug butterfly valve, double flange concentric butterfly valve, double flange eccentric butterfly valve, balance valve, wafer dual plate check valve, Y-Strainer and so on. At Tianjin Tanggu Water Seal Valve Co., Ltd., we pride ourselves on providing first-class products that meet the highest industry standards. With our wide range of valves and fittings, you can trust us to provide the perfect solution for your water system.
Post time: Feb-29-2024