Valve on the hand wheel, the handle is normal human design, therefore, the use of the provisions of the valve does not allow the operator to use the lever and long wrench to open or close the valve. Handwheels, handwheels with a diameter (length) of <320 mm, only for personal operation, handwheels> 320 mm in diameter, allowing the two to operate together or allowing one person to operate the valve by means of a suitable lever, typically not more than 0.5 m long. But the diaphragm valve, pinch valve, non-metallic valve is prohibited to use the lever or long wrench operation, nor allowed to close the valve too. Valve such as gate valve and stop valve, closed or open to the end (ie, bottom dead center or top dead center) to be rotated 1/4 ~ 1/2 laps, so that the thread is better close together, the operation is advantageous, so as not to overstress, Damage to the valve. Some operators are accustomed to using the lever and long wrench operation, that the greater the closing force the better, in fact not the case. This will cause premature valve damage, and even lead to accidents.