What type of valve should be used for a shut off on a main steam line? Due to above specified challenges, ball valves are mostly used in shutoff applications. Ball valves are commonly used in steam, water, oil, gas, air, corrosive fluids. They can handle slurries and dusty dry fluids.
Which type of valves is best used with steam? By far the most widely used valve type for the automatic control of steam processes and applications is the globe valve. It is relatively easy to actuate, it is versatile, and has inherent characteristics well suited to the automatic control needs of steam.
How do you choose a valve type? Determine the pressure and temperature requirements. Find out both the temperature and pressure ranges where the valve will be installed. Metal valves tend to withstand higher temperatures and pressures than plastic valves. Metal valves are also usually best for pressurized gases.
Can butterfly valves be used for steam? Butterfly valve is not recommended to be used in steam pipeline, because the high pressure inside the valve, it’s difficult to switch and the sealing surface is easy to damage, so it cannot be frequently switched, so the butterfly valve does not put up good performance as the gate valve; However, if the pipeline
What type of valve should be used for a shut off on a main steam line? – Related Questions
How do I choose a steam valve?
Proportional control valves should be sized using a pressure drop through the valve of 80% gauge inlet pressure (PSIG) for low pressure steam systems. (Low pressure is generally defined as systems carrying 15 PSIG of less.) For steam pressures over 15#, recommended pressure drop is 50% of inlet gauge pressure.
Why Ball valves are not used in steam service?
Limitations or Ball Valves
Ball valves, like all valves, are generally rated at a lower pressure for steam service than for liquid or dry gaseous service. Wet steam is damaging to all valve parts at the moment of opening and closing, or when throttling.
Which valves are used in very high pressure and temperature services?
Globe valves are linear motion valves with rounded bodies, from which their name is derived. They are widely used in industry to regulate fluid flow in both on/off and throttling service. Advantages include precise throttling and control, as well as high-pressure limits.
How do I choose a valve size?
When sizing a control valve, the rule of thumb is to size it so that it operates somewhere between 20-80% open at maximum required flow rate and whenever possible, not much less than 20% open at the minimum required flow rate.
How do I calculate valve size?
The volume flow rate for liquids can be calculated by multiplying the fluid velocity times the flow area. Thus, Cv is numerically equal to the number of U.S. gallons of water at 60°F that will flow through the valve in one minute when the pressure differential across the valve is one pound per square inch.
Is globe a valve?
A globe valve, different from ball valve, is a type of valve used for regulating flow in a pipeline, consisting of a movable plug or disc element and a stationary ring seat in a generally spherical body. This has an opening that forms a seat onto which a movable plug can be screwed in to close (or shut) the valve.
What is the best valve to use on a steam header?
For steam service, parallel slide valves are the preferred option in which high temperature swings occur after valve closure. Wedge gate valves may be used as an alternative for general isolation duty or if good, low pressure leak tightness is required.
What valves are used for steam?
The following article will cover the general mechanism and function of the most typical of these valves used in steam systems, such as ball valves, butterfly valves, globe valves, gate valves, and diaphragm valves.
Can a butterfly valve be used for isolation?
Butterfly valves offer true isolation and control capabilities in a single product. Designed for accurate flow and pressure control, they are ideal in applications where positive isolation is required.
Which type of valves is best used for abrasive scaling and aggressive media?
Pinch valve: ideal for abrasive slurry
Good slurry valve selection for processes which include abrasive, corrosive and scaling slurries is a high-quality pinch valve. The reason pinch valves are ideal is that they are one of the only self-cleaning valves.
What is main steam valve?
Main Steam Isolation Valve – usually an air operated or motor operated valve used to isolate the steam source from the turbine. Power Operated Relief Valves – large air or motor operated valves that usually lift at a setpoint lower than the safety valves – in order to keep the steam pressure from getting too high.
What is steam stop valve?
A main steam stop valve is a valve usually connected directly to the boiler for the purpose of shutting off the steam from the main steam line.
Can you use ball valve steam line?
Ball valves are commonly used in steam, water, oil, gas, air, corrosive fluids. They can handle slurries and dusty dry fluids. Ball valves are not used with abrasive and fibrous materials as it poses risk of damage to the seat and plug surface.
Why do we use ball valves?
Ball valves are shutoff valves that use a ball to stop or start the flow of fluid downstream of the valve. This allows fluid flow to pass through the valve. When the ball is rotated so that the hole is perpendicular to the flow path, the flow stops.
What valve should be used if the fluid passing through is very thick or corrosive?
Diaphragm valves are ideal for handling corrosive, erosive, and dirty services. There are many advantages to using diaphragm valves: they are extremely clean, feature a leak-proof seal, have a tight shut-off, are easy to maintain, and reduce leakage to the environment.
Which type of valve is best for controlling the flow?
Globe valves are considered the industry standard for control valves because they are good at regulating flow, whereas ball valves are better for on/off control without pressure drop.
What valves are used for throttling?
The two main types of valves that we offer for throttling applications are our globe valves and our needle valves. In both these types of valves a stem is raised and lowered into the flow path and can be stopped at any point and left in that position.
What is CV in control valve sizing?
Valve Flow Coefficient (Cv) is the flow capability of a control valve at fully open conditions relative to the pressure drop across the valve. It is defined as the volume of water (GPM in the US) at 60°F that will flow through a fully open valve with a pressure differential of 1 psi across the valve.
How do you calculate valve CV?
Cv by definition is the number of gallons per minute (GPM) a valve will flow with a 1 psi pressure drop across the valve. For example a valve with a Cv of 10 will flow 10 GPM with a 1 psi pressure drop. The formula used to select the valve Cv with the specified differential pressure is: Cv=GPM/((SQ RT(∆P)).
How do I know if my globe valve is open?
If the handle on top is parallel to the valve, it’s open. Likewise, if the handle is perpendicular to the top, the valve is closed.
Are globe valves expensive?
Globe valves generally seal better than gate valves and last longer. They are more expensive than similarly sized gate valves, but may be worth the extra expense in situations where throttling is needed.