NKZ41H Flanged Vacuum Butterfly Valve Introduction:

NKZ41H flanged vacuum gate valves are suitable for piping systems with working temperatures ≤ 425°C and working media such as water, steam, or air, serving as an opening and closing device; particularly for thermal power plant turbine condensation and vacuum negative pressure systems, providing vacuum isolation and sealing. These vacuum gate valves are an improved version of standard manual gate valves, distinguished by an additional vacuum sealing ring at the stuffing box, which has an automatic self-tightening function. They offer better gas-tight performance compared to standard gate valves.

NKZ41H Flanged Vacuum Gate Valve Structural Features:

The vacuum gate valve's closing element is a gate plate, which moves perpendicular to the fluid direction. The gate valve can only be fully open or fully closed, not for regulation or throttling. The gate plate has two sealing surfaces. The two sealing surfaces of the commonly used pattern gate plate valve form a wedge shape, with the wedge angle varying with the valve parameters, usually 5°, and 2°52 when the medium temperature is not high.The gate disk of a wedge gate valve can be made as a single unit, known as a rigid disk; or as a disk capable of slight deformation to enhance its processability and compensate for the angle deviations that occur during machining, which is called an elastic disk. This valve is typically installed horizontally.

When the vacuum gate valve is closed, the sealing surface can be sealed solely by the medium pressure, i.e., the medium pressure pushes the sealing surface of the gate plate against the opposite valve seat to ensure the sealing of the surface, which is known as self-sealing. Most gate valves use forced sealing, meaning that when the valve is closed, external force is needed to forcibly press the gate plate against the valve seat to ensure the sealing integrity of the sealing surface.

The gate of a vacuum globe valve moves in a straight line along with the valve rod, known as a lifting rod globe valve (also known as a top-lug globe valve). Typically, there is a trapezoidal thread on the lifting rod, which converts rotational motion into linear motion through the nut at the top of the valve and the guide slots on the valve body, thereby transforming the operating torque into an operating thrust.

When opening the valve, the fluid passage is fully open when the gate lifting height is equal to the valve's bore diameter (1:1 ratio). However, this position is unmonitored during operation. In actual use, the top of the valve rod is used as a reference, marking the fully open position where it cannot be opened further. To account for locking due to temperature changes, it is typically adjusted by reversing 1/2 to 1 turn from the top position, establishing the fully open valve position. Therefore, the fully open position of the valve is determined by the gate's position (i.e., stroke >).

Some gate valves have the valve stem nut mounted on the gate plate. When the handwheel is turned, it drives the valve stem to rotate, lifting the gate. Such valves are known as rotating stem gate valves or blind stem gate valves.

NKZ41H Flanged Vacuum Gate Valve Product Ordering Instructions:

1. Once the customer has confirmed the type and model of the valve (especially non-standard models), they should accurately describe the meaning and requirements of the model.

2. Customers should order based on the product models listed in the sample. If there are any special requirements for the product items, please specify them in the order.

1) Structural Length 2) Flange Standard 3) Valve Structural Design: such as full bore or reduced bore passage, body and cover connection type 4) Valve internal parts and other material requirements 5) Pressure Test, Inspection Standards, Marking, and Other Requirements

3. When the application of the valve is crucial or the environment is complex, please provide design drawings and detailed specifications. Our experts will review and ensure quality control for you.

4. Our company can customize electric devices, pneumatic drives, and turbine units according to specific customer requirements.

5. Our valves of various types meet all requirements specified in the order. Each product undergoes rigorous inspections and tests in accordance with the relevant standards prior to shipment.

6. All products of Zhong Zhi Valves come with a warranty period of 12 months from the date of customer's formal installation and use or 18 months from the date of product manufacture.