A manual knife gate valve is a valve device that achieves full opening and full closing through the vertical movement of a gate in the direction of the fluid. It cannot be used for flow regulation or throttling. It is mainly used in mining slag removal, wastewater treatment, petrochemical, food, and pharmaceutical industries. Its gate features a knife-edge design with a beveled cut at the bottom, capable of cutting media containing fibers and particles, and is equipped with a shearing function to remove impurities from the sealing surface.
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manual knife gate valve Technical parameters
Size Range:2″ to 24″ (DN50-DN600)
Connection Options:Flanged, Threaded (NPT, BSP), Butt Weld, Socket Weld
Working Pressure:PN10/PN16
Working Temperature:-29°C to 425°C
Sealing Options:Metal-to-Metal, Resilient Seat, Graphite, PTFE
Manufacturing Method:Cast, Forged, Machined
Applicable Medium:Water, Oil, Gas, Steam, Chemical Fluids
manual knife gate valve Main Performance Specifications
Nominal Pressure PN (MPa) |
Test Pressure (MPa) | Working Temperature (℃) |
Applicable Medium |
|
|---|---|---|---|---|
| Shell | Seal | |||
| 1.0 | 1.5 | 1.1 | ≤100℃ (rubber) | Slag, pulp, sewage, cinder, ash, mud, oil |
| 1.6 | 2.4 | 1.8 | H / Y ≤ 425℃ | |
manual knife gate valve Main Material Specifications
| Body, Cover | Gate | Stem | Sealing Surface |
|---|---|---|---|
| Stainless steel, carbon steel, gray cast iron | Carbon steel, stainless steel | Stainless steel | Rubber, PTFE, stainless steel, hard alloy |
manual knife gate valve Structural Features
- Gate Design: The gate typically employs a blade-like design, providing shearing capabilities to cut through fibers, pulp, and other impurities in the medium, preventing valve blockage and ensuring unobstructed pipeline flow.
- Sealing Surface: The gate has two sealing surfaces, most commonly forming a wedge shape. The wedge angle varies depending on the valve parameters, but is typically 50°. The gate of a wedge-type knife gate valve can be made as a single piece (rigid gate) or as a gate capable of slight deformation (elastic gate) to improve manufacturability and compensate for deviations in the sealing surface angle during processing.
- Valve Body Structure: The valve body features a rational design, simple and compact structure, smooth flow path, and low flow resistance, minimizing energy loss during medium flow.
manual knife gate valve Working Principle
- Closed Process: The drive unit moves the valve stem downwards, the gate descends along the guide rail, and the sealing surface tightly contacts the valve seat, cutting off the flow of media.
- Opened Process: The drive unit moves the valve stem upwards, the gate moves away from the valve seat, and the media flows through the valve.
- Sealing Mechanism: Some valves rely on media pressure to achieve self-sealing (one-way), while most use forced sealing (requiring external force to press the gate).
manual knife gate valve Performance Advantages
- Reliable Sealing: The manual knife gate valve boasts excellent sealing performance, primarily relying on the medium pressure to press the gate's sealing surface against the valve seat on the other side to ensure a tight seal. In the closed state, external force can be used to forcibly press the gate against the valve seat, further enhancing the sealing effect.
- Easy Operation: Manual operation makes opening and closing the valve simple and quick, requiring no additional power source.
- Wear and Corrosion Resistance: The gate and valve seat are typically made of wear-resistant and corrosion-resistant alloy steel, stainless steel, or special coating materials to withstand various harsh working environments.
- Low Maintenance Costs: The manual knife gate valve has a simple structure, is easy to manufacture, install, and maintain, reducing operating costs.
manual knife gate valve Applicables
Manual knife gate valves have a wide range of applications, including but not limited to the following:
- Paper Industry: Used for handling media such as pulp and fibers, cutting off impurities in the media and ensuring unobstructed pipeline flow.
- Wastewater Treatment: Used in urban wastewater treatment plants and industrial wastewater treatment systems to remove suspended solids, fibers, and other impurities from wastewater.
- Mining Industry: Used in coal preparation and slag removal operations in mines, handling media containing impurities such as coal gangue and ore particles.
- Food Industry: Used to control the transport of fluid materials in food processing, such as in the production of milk, juice, and beer, allowing for the cutting off and conduction of these materials in pipelines.
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