What Is The Purpose Of A Stop Valve?

The cut-off valve is a valve that controls fluid flow and regulates flow by rotating the stem so that the disc is tightly fastened to the seat. It's very versatile, very critical. Here's a breakdown:
1.Core Purpose: Cutting and regulating fluids
Cut off fluid flow
Function:"the"on/off"control piping pipeline system the complete sealing of valve disc and seat to prevent flow (liquid, gas, steam, etc.).
Application scenario:
Home water supply: When the faucet is turned off, the stop valve cuts off the flow.
Industrial piping: Shut off the stop valve and isolate the medium before repairing the equipment.
Fire system: Cutting off water or gas supplies in an emergency.
Regulate fluid flow
Function: To adjust the flow rate by partially opening the disc and changing the cross section volume of the fluid channel.
Application scenario:
Boiler feed water system: Accurate control of water level to prevent dry burning or overflow.
Chemical production: adjust feed speed of reactor, control reaction conditions.
Air conditioning System: Adjusts the flow of cooling water and controls the temperature of the room.
2. Key features: Sealability and pressure resistance
High sealing
Design principle: Disc and valve seat are conical or flat sealing, valve stem pressure is used to close, leakage rate is extremely low.
Advantages: Suitable for high pressure gas pipeline, toxic media transportation, etc.
High pressure, high temperature resistance;
Material selection: The body is usually made of cast, stainless steel or alloy steel, and the disc and valve seat can be made of hard alloy or surface abrasionresistant material.
Application scenarios:
Steam pipe: high temperature, high pressure steam, to ensure long-term stable operation.
Petrochemicals: When conveying corrosive media, corrosion-resistant materials can extend the valve's service life.
3. Typical application scenarios
1. Industrial sector
Oil and gas:
wellhead device: controls fluid flow during oil and gas extraction.
Oil pipeline: Adjust flow rate to prevent media backflow.
Electricity industry:
Boiler feed water system: accurate control of water level to ensure the efficiency of power generation.
Steam piping: Adjusts steam flow to meet the needs of different equipment.
Chemical production:
Reactor feed: adjust feedstock feed speed, control reaction process.
Storage tank emissions: safe discharge medium to avoid the risk of overpressure.
2. Civil and public facilities
Water supply system:
Domestic faucet: control water flow switch, adjust water volume.
Municipal pipeline network: When water supply is divided, different areas are separated by cut-off valves.
Heating system:
Radiator control: Adjust hot water flow and control indoor temperature.
Boiler room: Control the start and stop of circulation pump, maintain system pressure.
Gas pipelines:
Domestic gas meter front valve: cut off gas supply in an emergency.
Market gas pressure regulation station: adjust gas pressure to ensure transportation safety.
3. Special circumstances
Nuclear power plant:
Cooling water system: control the flow of reactor coolant to prevent overheating.
Emergency response system: in an emergency, quickly cut off the medium, to prevent the accident from expanding.
Aerospace:
Rocket propellant Pipeline: Precise control of propellant flow to ensure launch safety.
Aircraft hydraulic system: regulating the flow of hydraulic oil and controlling the movement of the rudder.
4. Comparison of cut-off valves with other valves
Characteristics Stop valve Gate valve Ball valve
Structured disc moves gate along valve seat axis vertically moves ball around axis
High seal height High (conical/flat seal) (large contact area of contact between gate and valve seat) High (soft seal or metal seal)
Large (fluid needs to be redirected) Small (straight-through flow channel) Very small (full-bore design)
Adjustment performance Excellent (precision controlled opening) poor adjustment (full opening/full closing only) poor adjustment (full opening/full closing only)
Slow on and off (multiple spins required) Fast (linear motion) Fast (90° rotation)
Fast opening and closing of largecaliber, low flow resistance or low flow resistance for situations requiring flow adjustment or high high-pressure sealing
V. Selection and maintenance points
1. Selection basis
Moderate characteristics:
Corrosive media: use stainless steel or corrosion resistant alloy valves.
Medium containing particles: Avoid the use of soft sealing valves to prevent abrasion and leakage.
Pressure and temperature:
High pressure system: select forged valve body to ensure strength.
High temperature system: choose high temperature resistant material (such as chrome-molybdenum steel).
Flow regulation requirements:
Precise regulation is required: select stop valve with linear flow characteristics.
Switch only: Select Quick stop valve.
2. Requirements for maintenance
Periodic inspection:
Check the valve disc and valve seat sealing surface for wear and tear and replace seals in a timely manner.
Remove impurities from the valve body to prevent blockage or stagnation.
Lubrication and maintenance:
Grease stem threads to reduce wear and tear.
When not in use for a long time, close the valve and drain the medium to prevent corrosion.
Fault management:
Leak: Check for the sealing surface damage, adjust valve stem pressure or replace seal.
Difficulties in opening and closing: cleaning the valve stem of impurities, checking whether the transmission mechanism is jammed.
VI. INTRODUCTION Abstracts
The cut-off valve realizes the core functions of fluid opening and closing and flow regulation through the sealing design of the disc and valve seat. It has Its high sealing, pressure resistance and regulation performance, and is an indispensable component of industrial and civil systems. From domestic water supply to cooling of nuclear power plants, from chemical production to aerospace, stop-valves play a crucial role in ensuring safe and stable operation of systems. Proper selection and regular maintenance are key to ensuring its long-term reliability.