The core operation of a gate valve is as follows: clockwise to close, counterclockwise to open, and handwheel rotation to control water flow.
After understanding the operating logic, first identify the valve type. For common rising stem gate valves, the opening/closing state can be determined by observing the rise and fall of the valve stem: downward movement indicates closed, upward movement indicates open. For non-rising stem gate valves, the number of handwheel rotations is required; typically, 4-6 rotations are needed to fully open.
When dealing with rusty valves, WD-40 rust inhibitor can be sprayed onto the valve stem threads and left to stand for 10 minutes before operation. Under pressure in the pipeline, it is recommended to open the bypass valve first to balance the pressure before operating the main valve to avoid wear on the sealing surface.
Video tutorials can be found by searching keywords such as "gate valve operation" and "household valve repair" on Douyin/Kuaishou's lifestyle skills channels or Bilibili's industrial science popularization section.
Household cast steel gate valves and industrial bronze gate valves have different torque requirements; the former requires the use of an F-wrench for auxiliary rotation. Bellows gate valves used in chemical pipelines have a double sealing structure; an additional 15 degrees rotation is required when opening and closing to ensure complete sealing surface contact. Special valves such as those used in gas pipelines must be operated by certified personnel.
