1. The trapezoidal thread of the valve stem of the rising stem gate valve is placed outside the oil circuit board, and is located on the upper end of the valve stem. By turning the valve stem nut, the valve stem pushes the gate plate to rise and fall synchronously to achieve the opening and closing of the gate valve, so it is very easy Identify the opening and closing of the gate valve to prevent operational errors. Because the valve stem nut is outside the renal tube, it is beneficial for lubrication, and at the same time the opening and closing conditions are clearly visualized, so it has a wide range of uses. However, in harsh environments, the exposed threads of the valve stem are easily damaged and corroded, and even affect the actual operation. Its main disadvantage is that the height of the gate valve is large after it is opened. Usually, a stroke arrangement needs to be added on the premise of the original relative height of the gate valve, so a very large lifting space is required.
2. The rising stem gate valve, also known as the rotary stem gate valve (also known as the rising stem wedge gate valve), is placed on the internal structure of the oil circuit board and is in contact with the material, and is often fixed on the gate plate. According to the rotation of the valve stem of the rising stem gate valve, the stem nut pushes the gate plate to make an adjustment movement to complete the opening and closing. Usually, there is a trapezoidal thread at the bottom of the stem of the rising stem gate valve. According to the thread at the bottom of the rising stem gate valve and the chute in the piston valve, the rotary motion is changed into a uniform linear motion. In fact, the actual operating torque is changed into the actual Operational driving force. Because the trapezoidal thread used in the transmission system is located in the internal structure of the oil circuit board, it will be corroded by substances and cannot be lubricated. The opening level cannot be directly observed, and an additional marking device is required. However, the valve stem of its rising stem gate valve does not perform adjustment movements, and requires a small lifting space, so the applicable parts are relatively limited and places where pipelines are concentrated.
