2.4 The center of the valve handwheel is 750~1500mm from the operating surface, and the most appropriate height is 1200mm. The installation height of the valve that does not need frequent operation can reach 1500~1800mm. When the installation height cannot be lowered and frequent operation is required, the operating platform or step shall be set during design. The valves on pipelines and equipment of hazardous media shall not be set within the height range of human head.
2.5 When the center of the valve handwheel is more than 1800mm from the operating surface, the chain wheel should be set for operation, and the chain of the sprocket should be about 800mm from the ground, and the chain hook should be set up. The lower end of the chain should be hung on the nearby wall or column to avoid affecting the passage of the channel.
2.6 For the valve set in the pipe trench, when the trench cover plate is opened for operation, the hand wheel of the valve shall not be 300 mm below the trench cover plate; when it is less than 300 mm, the valve extension rod shall be set to make its hand wheel within 100 mm below the trench cover plate.
2.7 When the valve set in the pipe trench needs to be operated on the ground, or the valve installed below the upper floor (platform), the valve extension rod can be set to extend it to the trench cover, floor and platform for operation. The hand wheel of the extension rod should be 1200mm from the operating surface. The valve with nominal diameter less than or equal to DN40 and threaded connection shall not be operated with chain wheel or extension rod to avoid damaging the valve. In general, the use of sprockets or extension rods to operate the valve should be minimized.
2.8 The distance between the valve handwheel arranged around the platform and the platform edge should not be more than 450mm. When the valve stem and hand wheel stretch into the upper part of the platform and the height is less than 2000mm, it shall not affect the operation and passage of the operator, so as to avoid personal injury.
Unfinished (to be continued) ……
Post time: Nov-21-2022