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Pinch Valve Advantage and Disadvantage

Pinch Valve Advantage and Disadvantage

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Pinch Valve Advantage and Disadvantage

Pinch Valve is made using a metal frame that houses a rubber wear sleeve and a shut-off mechanism. The rubber sleeve is the only part that comes in contact with the flowing media; this significantly minimizes the chances of contamination within the system.

Depending on the application, the rubber sleeve is hand-built with different kinds of rubber compounds to make it suitable for the required application. Pinch valves have a full bore design with no mechanical parts and quick closing mechanism. They require little to no maintenance, additionally changing the rubber sleeve is very easy.

Relatively inexpensive linear motion pinch valve consists of a flexible tube (rubber tubing) that is mechanically pinched from the outside of the valve body.

Pinch valves are suitable for on-off and throttling services. However, the effective throttling range is usually between 10% and 95% of the rated flow capacity. Pinch valves are ideally suited for the handling of slurries, liquids with large amounts of suspended solids, and systems that convey solids pneumatically.

Because the operating mechanism of the valve is completely isolated from the fluid, these valves also find application where corrosion or metal contamination of the fluid might be a problem.

Pinch valves benefits

Some of the benefits of pinch valves are:

  • Minimal turbulence
  • Low maintenance
  • Excellent drainage
  • Very Clean
  • Low weight
  • Inexpensive
  • Low airborne contaminants

Pinch valves are preferred over other types of valves because of their low cost, easy maintenance, and full bore design offering zero leakage. They can be used in a diverse range of applications.

Advantages of Pinch Valve

  • It can be used for application where corrosion or metal contamination of the fluid might be a problem. Flow from the valve is straight without any obstruction.
  • There are no internal moving parts in contact with the fluid hence, low maintenance cost.
  • Inexpensive due to simple construction

Disadvantages of Pinch Valve

  • It cannot be used in high temperature-pressure applications and gas media.

Application of Pinch Valve

  • Gauge protection: Install directly in the fluid line or put a tee in the line and attach the valve to the leg of the tee.
  • Motion control: Hold rods and shafts in a fixed position. Use for linear or rotational motion control.
  • Pneumatic conveying: Control fluidized dry material.
  • Pressure relief: Use actuation pressure to close the valve at “normal” operation pressures for the system.
  • Surge protection: Modulate surges in pressure or flow rate in a piping system.
  • Throttling: Valves can maintain a lower actuation/controlled material pressure differential that is required for complete closure.
  • Vacuum receiver: Can eliminate the need for the periodic shutdown of the system to empty a receiver.
Butterfly Valve

Butterfly Valve Advantages and Disadvantages

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Butterfly Valve Advantages and Disadvantages

A Butterfly Valve is a shut-off valve with a relatively simple construction. In a closed position, the disc blocks the valve bore while in an open position, the disc turn allows flow. A quarter turn takes the valve from fully open to a fully closed position or the opposite, and thus the butterfly valve allows for quick opening and closure.

Butterfly valves can be used for a broad range of applications within water supply, wastewater treatment, fire protection, and gas supply, in the chemical and oil industries, in fuel handling systems, power generation etc. Some of the advantages for this type of valve are the simple construction not taking up too much space, and the lightweight and lower cost compared to other valve designs.

The valves can be operated by handles, gears or actuators according to any specific need.

Types of Butterfly Valves

Butterfly valves have been around for a long time, and are used for a variety of applications. They made their first appearance during the 1930s, and have been utilized by several industries ever since.

Often made out of cast iron, butterfly valve’s name is based on the functionality of its disc. There are a few different types of butterfly valves, however, they fall into two basic types – Lug and Wafer valves.

LUG BUTTERFLY VALVE

The lug version of the butterfly valve’s design is similar to a 3-piece ball valve in that one end of the line can be taken off without having an effect on the opposing side. This can be executed by using threaded inserts, flanges, along with two sets of lugs (bolts) that don’t utilize nuts since each flange features its own bolts. It’s also important to note that you don’t need to shut down the entire system in order to clean, inspect, repair, or replace a lug butterfly valve (you would need to with a wafer butter valve).

WAFER BUTTERFLY VALVE

A wafer butterfly valve’s function is to retain a seal to protect against dual-directional pressure differential in the flow of fluid. In other words, the wafer version of butterfly valves was designed to hold a tight seal, safeguarding against bi-directional pressure differential in order to avoid any backflow in systems that have been manufactured for uni-directional flow.

This is accomplished by using a tightly fitted seal, such as an O-ring, gasket, precision machined, along with a flat valve face on the downstream and upstream sections of the valve.

Both lug and wafer butterfly valves are used in a number of applications for industrial sectors that include food processing, pharmaceutical, chemical, oil, water as well as wastewater management.

Butterfly valves, for the most part, have replaced ball valves in a lot of industries. This is especially the case for those dealing with petroleum because they are less expensive and easy to install. It’s important to note that pipelines that contain butterfly valves can’t be ‘pigged’ for cleaning. “Pigging” is the process of making use of devices referred to as “pigs” to carry out a variety of maintenance operations.

BUTTERFLY VALVE APPLICATIONS

  • Cooling water, air, gases, fire protection.
    • Slurry and similar services.
    • Vacuum service.
    • High-pressure and high-temperature water and steam services.
    • Compressed air or gas applications.

Advantages of a Butterfly Valve

  • The compact design requires considerably less space, compared to gate, globe, or other valves.
  • Light in weight.
  • Quick acting; as a quarter-turn valve, it requires less time to open or close.
  • Butterfly Valve is available in large sizes, ranging from NPS 1¹⁄₂ (DN 40) to over NPS 200 (DN 5000).
  • They have low-pressure drop and high-pressure recovery.
  • Provide bubble-tight service.

Disadvantages of a Butterfly Valve

  • Butterfly Valve Throttling service limited to low differential pressure.
  • Cavitation and choked flow are two potential concerns.
  • Butterfly Valve disc movement guides and affects by flow turbulence

 

Ball Valve

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Ball Valve

A Ball Valve is a device with a spherical closure unit that provides on/off control of flow. The sphere has a port, also known as a bore, through the center.

When the valve is positioned such that the bore is aligned in the same direction as the pipeline, it is in open position and fluid can flow through it. When rotated 90 degrees, the bore becomes perpendicular to the flow path, meaning the valve is closed and the fluid cannot pass through.

Valve ultilize for control/flow/stop the fluid (water/air/gas) in piping, and there are many kind of valves. These valves generally classified kind of valves depend on application and purpose of using.

There are 4 kind of concepts “Pushing” “Rotating” “Sliding” “Squeezing” for valve’s action. And Ball Valve is classified concept “Rotating” by sealing style.

For strong(merit) points are resistance of fluid is quite little because the port size is same with piping line, and operation is easy and able to do for short time operation by quarter turn operation style.

As the name suggests, ball valves are valves that use a ball to control the flow of substances from one opening to the next. These valves work by allowing the hole to be open, blocked, or open partially to regulate the flow of gas/liquid.

Ball valves are the ideal choice for using with gases as they are able to offer better sealing. They are very versatile as they support pressures up to 700 bars and temperatures up to 200°C and sizes typically range from 0.5 cm to 30 cm. They are easy to operate and repair as they contain a simple structure.

They are designed with special measures that permit only a 90-degree rotation which is required for the opening and closing of ball valves. These valves are a notable industrial choice because of their reliable and air-tight sealing when in the closed position.

Advantages

  • They contain a compact and low-maintenance design that requires no lubrication
  • They are cost-effective among all of the valves
  • The biggest advantage of ball valves is that they have poor throttling characteristics that can cause the seat of a ball valve to easily erode.
  • They provide leak-proof service.
  • They open and close quickly.
  • Ball valves have multi-way design flexibility.

Disadvantages

  • Ball valves are not suitable for permanent throttling.
  • In residual fluids, the particles in the fluid collide with the surfaces and stick to them. This may cause leakage, abrasion, and other problems.

Applications

  • Ball Valves are used for flow and pressure control and shut off for corrosive fluids, slurries, normal liquid and gases.
  • They are used in the oil and natural gas industry, but also find a place in many manufacturing sectors, chemical storage, and even residential uses.

Ball Valve

Types of Ball Valves

There are five general body styles of ball valves: single body, three-piece body, split body, top entry, and welded.

The difference is based on how the pieces of the valve—especially the casing that contains the ball itself—are manufactured and assembled. The valve operation is the same in each case. In addition, there are different styles related to the bore of the ball mechanism itself.

What is a full port or full bore ball valve?

  • Has a straight flow path
  • Offers little or no resistance to flow
  • The flow path through the valve does not become narrower on the inside

The inner diameter of the pipe coming into a full bore valve is the same diameter as the flow path through the valve body and out through the other side of the valve. Most full bore valves are two-way, quarter-turn ball valves.

What is a standard port or standard bore ball valve?

  • Has a straight flow path
  • Flow restriction produces a pressure drop
  • The flow path through the valve becomes narrower on the inside

A standard bore valve body is about the same diameter as the pipe or tube coming into and exiting it. The working part of the valve is the ball inside the valve body. Since the working part of the valve fits inside the valve body, the bore through the valve ball is smaller than the diameter of the valve’s connecting pipe or tube.

 

gate valve

Gate Valve Type, Advantage and Disadvantage, Applications

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Gate Valve, Type, Advantage and Disadvantage, Applications

Gate valves are widely used for all types of applications and are suitable for both above-ground and underground installation. Not least for underground installations, it is paramount to choose the right type of valve to avoid high replacement costs.

Gate valves are designed for fully open or fully closed service. They are installed in pipelines as isolating valves, and should not be used as a control or regulating valves.

Operation of a gate valve is performed doing an either clockwise to close (CTC) or clockwise to open (CTO) rotating motion of the stem. When operating the valve stem, the gate moves up- or downwards on the threaded part of the stem.

gate valveHistory of a gate valve

The term Gate Valve originated from the words gatan, gap, gasse and gat, and implies a passage with a barrier, which can be hinged on one side, allowing it to be OPENED and CLOSED.

Some of the first known gate valves were used by the Egyptians, Greeks, and Romans when irrigating fields with water. These were simple wooden barriers, but they were well-suited for the requirements of the task.

In the 19th century, intensive development of gate valves moved quickly forward due to their increasing use in industrial operations. Over time the materials involved in their manufacture were improved and modified to suit different applications.

In addition, there were significant improvements in the efficiency of both internal and external sealing methods.

Type of Gate Valve

There is a different type of gate valve, such as:

  • Standard
  • Wedge Types
  • Solid Tapered Wedge
  • Solid Pliable Wedge
  • Double Disc type
  • Bellow Design
  • Cryogenic Design
  • Knife Plate
  • Hulk Plate

Advantages of Gate Valves

  • The closing feature is very good.
  • These valves can be used both ways in the circuit
  • They provide laminar flow, the pressure loss is minimum

Disadvantages of Gate Valves

  • They cannot be opened and closed quickly.  To fully open or closed wheel or gearbox actuators, the shaft should be rotated as many as the full open revolution number.  The full open revolution number is equal to the pitch
  • Assembly, start-up, and maintenance require large space.
  • In the fully closed position, the slow movement of the slide causes high flow speed.  Due to vibration and collision, abrasion and deformation occur in the seating surfaces and the surface gets damaged from friction.
  • In systems where high-temperature changes irregularly, due to the load in the pipe at the valve end, leakages in gate valves occur.
  • At the place of operation, repair and maintenance of seating surfaces are difficult.

Application of Gate valve

  • Socket or butt-welding end-gate valves in air, fuel gas, feedwater, steam, lube oil, and other systems are typical applications. Threaded-end gate valves may be used in air, gaseous, or liquid systems.
  • Concern for leakage from threaded connection can be addressed by seal welding the threaded connection or by using thread sealants, as appropriate. In low-pressure and low-temperature systems such as fire protection systems’ water piping or water distribution pipelines, flanged gate valves are commonly used.

Refrences:

https://www.avkvalves.eu

http://www.schuf.de

http://www.pipingguide.net

https://www.ksb.com

 

What is a Globe Valve?

What is a Globe Valve?

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What is a Globe Valve?

A globe valve is a linear motion valve used to stop, start, and regulate the fluid flow. The globe valve disk can be removed entirely from the flow path, or it can completely close the flow path. During opening and closing of globe valve, disc moves perpendicularly to the seat.

The globe valve is used for throttling flow control.  Shut off is accomplished by moving the disc against the flow stream rather than across it as in the case with a gate valve.  The flow pattern through a globe valve involves changes in direction, resulting in greater resistance to flow, causing a high-pressure drop.

Advantages and disadvantages of Globe valves

ADVANTAGES:

  • Good shutoff capability
  • Moderate to good throttling capability
  • Shorter stroke (compared to a gate valve)
  • Available in tee, wye, and angle patterns, each offering unique capabilities
  • Easy to machine or resurface the seats
  • With disc not attached to the stem, the valve can be used as a stop-check valve

DISADVANTAGES:

  • Higher pressure drop (compared to a gate valve)
  • Requires greater force or a larger actuator to seat the valve (with pressure under the seat)
  • Throttling flow under the seat and shutoff flow over the seat

GLOBE VALVE APPLICATIONS

The following are some of the typical applications of globe valves:

  • Cooling water systems.
  • Fuel oil systems.
  • Feedwater or chemical feed systems.
  • Boiler and main steam vents and drains.
  • Turbine lube oil system and others.

Types of Globe Valve

There is three common type of valve.

Z-body type valve

This is the simplest and most commonly used design of globe valves, favorable for applications involving water flow. The name Z-shaped is derived from the Z shaped diaphragm or partition in the bulbous shaped body. The stem and the disc move at right angle to the valve body, aligning with the horizontally arranged seat. The stem passes through the bonnet attached to a wide opening at the top.

Z globe valve

Y-body type valve

The Y-body type valve design is a solution to the problem of pressure drop which is commonly found in globe valves. In this design, the valve seat and stem are angled at approximately 45° to the valve axis. This results in a much straighter path for the fluid flow, providing a more pressure resistant environment inside the valve.

The Y-body valves are mainly suited for high-pressure applications wherein problems related to pressure drop are common. However, in the case of throttling purpose, the pressure resistance might not work effectively, especially if the valve is smaller in size. This is also because, in smaller valves, the flow passage is not as carefully streamlined as that in larger vessels.

Y type globe valve

Angle Valve design

The angle globe valve is a modification of the design of the basic Z-shaped glove valve. The inlet and outlet ends are placed at right angles and the diaphragm is generally a simple flat plate. The fluid flows through the valve body in a right-angled flow path and gets discharged downwards in a more symmetrical manner. These characteristics are extremely important in applications involving high pressure. However, in moderate conditions, the valve functions more or less similar to the Z Shaped Valve.

Angle globe valve

Refrences:

https://medium.com

https://www.bmengineering.co.uk

http://www.ladishvalves.com

http://www.ladishvalves.com

https://www.emerson.com

Types of Valves

Types of Valves

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Types of Valves

In the industry, we have different Types of Valves , each with a specific application. In this article, we introduce the most widely used valves.

BALL VALVES

A ball valve is a shut-off valve that controls the flow of a liquid or gas by means of a rotary ball having a bore. By rotating the ball a quarter turn (90 degrees) around its axis, the medium can flow through or is blocked.

Floating Ball Valve

In floating ball valve, the ball is held in the position by the compression of the two elastomeric seats against the ball. The ball is free to float inside the valve body.  See the highlighted portion in the image and remember as you will see the difference when I will explain you about trunnion mounted ball valve.

ball valve

Trunnion Mounted Ball Valve

Trunnion mounted ball valve is a solution to the problem of excessive torque required by floating ball valve in high-pressure service. A short shaft like an extension that called trunnion set in the body. You can see this in the image.  In this design steam and ball work as a single unit. The ball is supported by two floating or spring-loaded seats that remain in constant contact with the ball.

Ball Valve

Gate Valve

Gate valves are widely used for all types of applications and are suitable for both above ground and underground installation. Not least for underground installations it is paramount to choose the right type of valve to avoid high replacement costs.

Gate valves are often used when minimum pressure loss and a free bore is needed. When fully open, a typical gate valve has no obstruction in the flow path resulting in a very low pressure loss, and this design makes it possible to use a pipe-cleaning pig. A gate valve is a multiturn valve meaning that the operation of the valve is done by means of a threaded stem. As the valve has to turn multiple times to go from open to closed position, the slow operation also prevents water hammer effects.

Globe Valve

A globe valve is a linear motion valve used to stop, start, and regulate the fluid flow. The globe valve disk can be removed entirely from the flow path, or it can completely close the flow path. During opening and closing of globe valve, disc moves perpendicularly to the seat.

This movement creates the annular space between the disk and seat ring that gradually close as the valve closed. This characteristic provides the globe valve good throttling ability required for regulating the flow.

Leakage from globe valve seat is less as compared to the gate valve, mainly due to right angle contact between the disk and seat ring, which allows tighter seal between seat the disk.

CHECK VALVES

Leak-free, tight sealing, protection against reverse flow and minimal flow direction changes are at the core of Flowserve check valve designs. A broad range of configurations that includes piston, tilting disc, spring-loaded disc and dual-plate models meets the critical, high-temperature/pressure demands of the world’s major industries. Customers can carefully match application requirements through myriad valve body, seat and disc options.

 

 

https://hardhatengineer.com/ball-valve-floating-trunnion-mounted-ball-valves/

https://hardhatengineer.com/globe-valve-types-angle-parts/

https://www.flowserve.com/en/products/valves/check-valves