Valve Manifold

Valve Manifold

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Valve Manifold

The Valve Manifold used to protect the DP transmitter and pressure gauge from a higher range. This device isolates the transmitter from fluid pressure for calibration and for maintenance purposes.

The manifold is a combination of valves in a single body. Each valve will have separate openings ad controls. The manifolds commonly use the ball, bleed, needle, and vent valves.

3-valve manifold

The 3-valve manifold consists of two shut-off valves and one pressure compensating valve. The shut-off valves separate the process from the differential pressure measuring instrument. The pressure compensating valve enables the compensation between ⊕ side and ⊖ side to avoid one-sided overpressure during commissioning and operation.

5-valve manifold

Compared to the 3-valve manifold, the 5-valve manifolds equipped with two additional vent valves. One vent valve per pressure side allows operators the targeted venting of one or both pressure sides of the measuring arrangement.

Through the non-rotating spindle tip, the wear of the sealing elements is reduced. This results, particularly with frequent opening and closing, in a noticeable increase in the service life of the valve manifold.

Advantages of a manifold valve

Manifold valves are used in a number of different applications, ranging from mobile machinery to heavy industrial equipment.

When included in fluid control and/or regulation system, valve manifolds have shown to improve efficiency as well as reduce energy costs. Other advantages include:

  • Shorter path flows which reduces pressure drop and heat fluctuations, improving the overall energy efficiency of the system
  • Reduction in installation costs as well as fluid connections because of a simpler, more compact design
  • Minimum chances of oil leak due to less number of connections, further reducing the need for upkeep against fatigue, wear and  lose joints
  • Improved layout due to fewer hoses and connections
  • Small, compact cartridge sizes which suits confined spaces

Applications

  • Shut off and vent pressure measuring instruments
  • For gaseous and liquid aggressive media that are not highly viscous or crystallizing, also in aggressive environments
  • Process industry: Oil & gas, petrochemical, chemical industries, power generation, water, and wastewater

 

 

Valve Actuator

Types and structure of Valve Actuator

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Types and structure of Valve Actuator

A Valve Actuator is a mechanical device that uses a power source to operate a valve. This power source can be electric, pneumatic (compressed air), or hydraulic (the flow of oil). There are two main types of actuators, one for each of the two main types of valves that require them.

Selection of the best actuator type for any application is dependent on many factors including:

  • Valve type
  • Power sources available
  • Environment of installation
  • Operational functions and characteristics
  • Cost

Types of Valve Operation

There are two primary types of valve actuators. Understanding how a valve operates is the first step in choosing the appropriate actuator.

  • Rotary Valve Actuators
    As the name implies, rotary valve actuators produce the rotational motion needed to operate roatary valves such as ball, plug, and butterfly valves. Rotary actuators are available in many different styles, each with its own benefits.
  • Linear Valve Actuators
    Linear valves such as a globe, gate, and pinch valves – due to their distinctly different operation – require actuators that are drastically different from the rotary type. These actuators must produce linear motion to operate the valve. They are also available in many styles.

Types of Valve Actuator

electric valve actuator1-Electric Valves Actuators

This type of actuator is motor-driven or what the name implies is powered by electricity. They come in various designs and sizes to match different valve applications.

Depending on the design, the power will either be direct current (DC) or alternating current (AC). This electricity will supply the necessary torque to open or close the valve. Since electric actuators rely on electricity, it would fail to operate when there is a power outage.

This is a disadvantage especially at critical times when the valve is in the vital process of opening or closing and got interrupted. There are cases when valves are hard to turn because they are seldom used or handling sticky or abrasive materials. When this happens, the operators will have to specify electric actuators with extra torque so they can turn the valve with ease.

For added assurance that the valve will be controlled anytime it is needed to, it is recommended to attach manual control wheels or handles.

It can also prevent motors from burn out or overheat because of much energy exerted from turning sticking valves. In order to protect the motor, there are various ways that can be employed such as electric current limiting sensors, motor overheats or over-torque. No matter what the type and the design of actuators; overload protection should be attached on it to prevent malfunction due to a stuck valve.

2-Hydraulic Valves ActuatorsHydraulic valve actuator

In contrast to electric actuators that rely on electricity to work, hydraulic actuators move mechanisms through water pressure or other fluid. They are commonly used in butterfly valves since it does not require a large opening within the pipe to control the flow of fluid. This type of actuator is not recommended to use in places which temperature reaches below freezing as when the water solidified, it will stop providing hydraulic energy needed for the operation.

 

 

3-Pneumatic Valves Actuators

This device, on the other hand, takes energy from a change of air pressure to produce motion. There are various types of pneumatic valves actuators such as rotary actuators, single or double acting pneumatic cylinders and diaphragm actuators. They produce various motions that are capable of moving the valve in the required direction.

  • Manual actuators are the most common type of valve actuators. Manual actuators include handwheels attached to the valve stem directly and handwheels attached through gears to provide a mechanical advantage.
  • Electric motor actuators consist of reversible electric motors connected to the valve stem through a gear train that reduces rotational speed and increases torque.
  • Pneumatic actuators use air pressure on either one or both sides of a diaphragm to provide the force to position the valve.
  • Hydraulic actuators use a pressurized liquid on one or both sides of a piston to provide the force required to position the valve.
  • Solenoid actuators have a magnetic slug attached to the valve stem. The force to position the valve comes from the magnetic attraction between the slug on the valve stem and the coil of the electromagnet in the valve actuator.

 

Valve Symbol

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Valve Symbol

A valve regulates, directs, or controls the flow of a fluid by opening, closing, or partially obstructing passageways in a piping system. This category includes rotameters, orifices, and other types of valves.

Piping and instrumentation diagrams, or P&IDs, are used to create important documentation for process industry facilities. The shapes in this legend are representative of the functional relationship between piping, instrumentation, and system equipment units.

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.

Globe Valve

Ball Valve

Ball valves are quarter-turn, straight-through valves that have around closure element with matching rounded seats that permit uniform sealing stress. The valve gets its name from the ball that rotates to open and close the valve. Ball valves are used in situations where tight shut-off is required. They are wide duty valves, able to transfer gases, liquids, and liquids with suspended solids (slurries).

ball valve

Plug Valve

A plug valve is shaped like a cylinder or cone and can be rotated inside the valve body to control flow of fluids. Plug valves have one or more hollow passageways often placed horizontally to allow ease of flow through the valve when open. The most common type of plug valve is the 2 port model with an open and closed position. The two ports are usually located on opposite sides of the valve with one passageway leading from inbound to outbound and the stem and handle located on the top. A plug valve also uses a quarter turn valve, which is useful where the quick and frequent operation is essential. The valve ends can be flanged, hub type, or butt weld.

plug valve

 

Check Valve

The valve that used to prevent backflow in a piping system is known as a check valve. It is also known as a non-return valve or NRV. The pressure of the fluid passing through a pipeline opens the valve, while any reversal of flow will close the valve. It allows full unobstructed flow and automatically shuts as pressure decreases. The exact operation will vary depending on the mechanism of the valve.

Check Valve

Needle Valve

A needle valve is a manual valve that used where continuous throttling of flow is required for regulation. Needle valves are similar to the globe valve in design with the biggest difference is the sharp needle like a disk.

Needle valves are designed to give very accurate control of flow in small diameter piping systems. They get their name from their sharp-pointed conical disc and matching seat.

Needle Valve

Pinch Valve

A Pinch Valve is an economical piece of equipment that works like a tap. It has an on/off function, to shut off, allow or control the flow of any media passing through it. The Pinch Valve is made up of three parts: Body / Housing, Internal rubber sleeve, End connections.

The rubber sleeve inside the body of the valve is the part that closes it. When in the open position, the Pinch Valve has a full and true bore. To close the valve, air pressure is supplied into an air nipple on the outer body, which then travels through into the internal part of the valve, pushing down onto the rubber sleeve which fully collapses and closes tightly.

Butterfly Valve

A butterfly valve is a flow regulating disc valve. A butterfly valve consists of a circular disc or plate built with a stem through the middle or attached offset. When opened, the disc pivots 90 degrees in the valve bore, aligning with the flow, creating a nearly unrestricted flow path. Butterfly valves operate similarly to ball valves in their 90-degree rotation and allow for quick shutoff.

butterfly valve

Gate Valve

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 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.

Gate Valve

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.
Types of Air Compressor

Types of Air Compressor

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Types of Air Compressor

A compressor increases the pressure of a gas. It reduces the volume of the gas and increases its density without turning that gas into a liquid. Compressors can do this in a number of ways.

However, the commonality between all compressors is the fact that they all use some sort of fuel, such as gasoline or electricity, to power whatever compression method they use.

Also, because the compressor increases the pressure on the gas, it increases the temperature of the gas. Many other types of compressors are used for various chemicals and fuels that require compression.

There are three popular Types Air Compressor :

  1. Reciprocating compressor
  2. Screw compressor
  3. Centrifugal compressor

They are often some of the most critical and expensive systems at a production facility and deserve special attention. Gas transmission pipelines, petrochemical plants, refineries, and many other industries all depend on this type of equipment.

Due to many factors, including but not limited to the quality of the initial specification/design, adequacy of maintenance practices and operational factors, industrial facilities can expect widely varying lifecycle costs and reliability from their own installations.

Various compressors are found in almost every industrial facility. Types of gases compressed include the following:

  • Air for compressed tool and instrument air systems
  • Hydrogen, oxygen, etc. for chemical processing
  • Light hydrocarbon fractions in refining
  • Various gases for storage or transmission
  • Other applications

There are two primary classifications of industrial compressors: intermittent flow (positive displacement), including reciprocating and rotary types; and continuous flow, including centrifugal and axial flow types.

Reciprocating compressor

A reciprocating compressor is a positive-displacement machine that uses a piston to compress a gas and deliver it at high pressure.

Reciprocating compressors are typically used where high compression ratios (ratio of discharge to suction pressures) are required per stage without high flow rates, and the process fluid is relatively dry.

Wet gas compressors tend to be centrifugal types. High flow, low compression ratio applications are best served by axial flow compressors. Rotary types are primarily specified in compressed air applications, though other types of compressors are also found in air service.

 

 

Screw Compressor

A screw compressor is a type of gas compressor that works on a rotary-type positive-displacement mechanism. A rotary screw compressor is commonly used to replace piston compressors wherein a large volume of high-pressure air is needed, either in large industries or to operate high power air tools. Oil-injected screw compressors are ideal for various industries and assembly production. With a capacity ranging from 7.5 KW to 37 KW, Mark Compressors provide you the best range of compressors. They have a simple LCD display control system, user-friendly design, uncompromised quality, and durability, and they even guarantee lasting performance. An oil-injected screw compressor can be used in the following industries,

  • Wastewater Treatment
  • Rubber and Plastics
  • Automotive
  • Apparel
  • Agriculture
  • Power Generation
  • Petroleum
  • General Manufacturing & many more.

Centrifugal Compressor

A centrifugal compressor is a type of dynamic compressor, or turbocompressor, with a radial design. Unlike displacement compressors that work at a constant flow, dynamic compressors work at constant pressure and the performance is affected by external conditions such as changes in inlet temperatures.

Air is drawn into the center of a rotating impeller with radial blades and is pushed toward the center by centrifugal force. This radial movement of air results in a pressure rise and the generation of kinetic energy. Before the air is led into the center of the impeller, the kinetic energy is also converted into pressure by passing through a diffuser and volute.

Each stage takes up a part of the overall pressure rise of the compressor unit. Depending on the pressure required for the application, a number of stages can be arranged in a series to achieve a higher pressure. This type of multi-stage application is often used in the oil and gas and process industries. Alternately, in wastewater treatment plants, low pressure, single-stage applications are used to achieve the desired pressure ratio.

In modern configurations of centrifugal air compressors, ultra-high speed electric motors are used to drive the impellers. This results in a compact compressor without a gearbox and associated oil-lubrication system, thus making it oil-free and appropriate for applications that require 100 percent oil-free air.

Plug Valves Advantages and Disadvantages

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Plug Valves Advantages and Disadvantages

A Plug Valve is a quarter-turn rotational motion Valve that use a tapered or cylindrical plug to stop or start the flow. In the open position, the plug-passage is in one line with the inlet and outlet ports of the Valve body. If the plug 90° is rotated from the open position, the solid part of the plug blocks the port and stops the flow. Plug valves are similar to Ball valves in operation.

Type of Plug Valve

  • lubricated plug valve
  • non-lubricated plug valve
  • eccentric plug valve
  • lift-type plug valve

Plug Valve Application

Plug valves are a type of flow control valve that allows the user to increase or decrease flow by rotating the handle or other similar operation. The user may have to adjust the valve to the desired flow rate, with the valve able to hold the flow rate consistently and reliably.

Other popular flow control valves include needle and fine metering valves, but they generally have more moving parts than plug valves, which makes them more expensive and harder to maintain.

Plug valves are typically used in applications where flow must be controlled and changed on a regular basis and where the user must have access to the valve.

Plug valves should not be used in applications where a constant, steady flow is required or where the valve does not need to be readily accessible.

Quarter-turn plug valves are the most common and involve a simple quarter turn on a handle to open and close the valve. They are economically priced and are commonly used for applications involving low-pressure throttle.

Advantages of Plug Valve 

  • one-piece valve body, top-loading design, simple structure, convenient maintenance, no leakage, supporting higher-strength pipe system.
  • The medium in the chemical process has strong corrosion resistance. In the chemical field, corroded valve body often can be seen. Therefore, the valve in the application of chemical process must have strong permeability and resistance to intergranular corrosion. The body of plug valve should be high-level casting, with casting quality of class II and precision of grade V.
  • Really simple internals. The plug is completely covered by the bushing. Body and plug have no wear. Replacing simple and economic bushing or top sealing device can complete the maintenance and update of the valve. Plug valve can reach long-term use requirement of 300 ℃, which has a considerable competitive edge compared with a ball valve that belongs to this application.
  • Top surface and flange are all the processing surface of the plug valve. Other parts are all one-time casting molding. The inside of the valve body has no processing. Comparing with the ball valve, it has the advantages of lower machining allowance. Especially, when the material is INCONEL, MONEL, HARTZ alloy, plug valve has the distinct advantage of price.
  • According to the user’s demand, various designs of plug valve can achieve a specific function. Plug valve is the best one of customized products. Plug valve is easy to cater to custom design, can be made into three-way, four-way, five-way and six-way valve; double valve group or valves group; all kinds of jacket requirements, etc.. For example, the six-way distribution valve used in the polyester industry is designed according to the requirements of patent owners, while the ball valve is difficult to make in line with custom design.
  •  Now, no clearance and face sealing is still the unique features of the plug valve. Although it has the design of the clearance like ball valve’s, the clearance just can be reduced to 1 ~ 3 mm at the most, which can’t achieve the application advantages of coated surface sealing. This characteristic of plug valves enables it to deal with a lot of harsh media, such as easy crystal and viscous fluid or those medium containing catalyst particles and deposit.
  • Coated bushing provides the characteristics of face sealing. It can be strictly controlled in accordance with the test requirements of zero leakage of API 598 soft sealing valve seat, achieving or sealing requirements of a stem of TA Luft or ISO 15848.
  • Comprehensive characteristics of plug valve are long service life, high reliability. It is a good choice for a lot of corrosive, abrasive and toxic fluid as well as continuously operated device. It has the application advantages and extensive applicability in the field of chemical industry.

Disadvantages of Plug Valves

  • The design of face sealing improves the requirements for driving torque. In the case of needing to be equipped with pneumatic actuators, compared with ball valve, it will cost much more. Such as the PP process, the main shut-off valve of it is the plug valve, rather than the ball valve, but the high-frequency switching valve is a ball valve. Therefore, basically, the pneumatic plug valves are applied to the key cut-off position. Plug valve is not recommended to apply it to the occasion of adjustment since the high-frequency switching is not the advantage of it. It is the cut-off valve of high reliability.
  •  In some applications, the incorrect choice of bushing material or improper design of the release area of bushing deformation may cause swelling for PTFE bushing materials, leading to the change of driving torque for several times.
  • Though the investment of plug valve is more than ball valve, as its advantages of reliability and the total cost of the life cycle are gradually accepted by users, more and more users will continue to use the plug valve.
Diaphragm Valve

Diaphragm Valves

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Diaphragm Valves

Diaphragm Valves use a ‘pinching’ method to stop the valve flow using a flexible diaphragm. They are available in two types: weir and straight-way. The most commonly seen of the two is the weir-type. This is because the straight-way type requires additional stretching of the diaphragm, which can shorten the diaphragm’s life-span.

One of the major advantages of using diaphragm valves is that the valve components can be isolated from the process fluid. Similarly, this construction helps prevent leakage of the fluid without the use of a gland seal (packing) as seen in other types of valves.

On the other hand, the diaphragm becomes worn more easily and regular maintenance is necessary if the valve is used on a regular basis. These types of valves are generally not suited for very high-temperature fluids and are mainly used on liquid systems.

Diaphragm valves are used on shut-off and throttling service for liquids, slurries and vacuum/gas.

The seal is achieved by a flexible membrane, usually elastomer, and possibly reinforced with a metal part. The membrane is tensed by the effect of a stem/compressor with linear movement until contact is made against the seal of the body.

The operating parts of the diaphragm valve are isolated from the flow. This makes this valve suitable for viscous flows and also hazardous, abrasive and corrosive flows as its sealing system avoids any contamination towards or from the environment.

Diaphragm valves are available in a wide variety of metals, solid plastics, plastic, rubber and glass linings. They are well suited to the handling of multiple chemical applications both clear fluids as well as slurries.

The diaphragm valve has an extended use for applications at low pressures and slurry fluid where most other kinds of valves corrode or become obstructed.

There are two types of diaphragm valves:

1- Weir

  • The Weir Diaphragm valve can be used for either off/on and throttling services

 

 

 

 

2-Straightway

  • named also Straight-Thru is only used for on/off services.

Advantages of Diaphragm Valve

  • Can be used as on-off and throttling service valves.
  • Offer good chemical resistance due to a variety of linings available.
  • Stem leakage is eliminated.
  • Provides bubble-tight service.
  • Does not have pockets to trap solids, slurries, and other impurities. It is suitable for slurries and viscous fluids.
  • These valves are particularly suitable for hazardous chemicals and radioactive fluids.
  • These valves do not permit contamination of flow medium, thus they are used extensively in food processing, pharmaceutical, brewing, and other applications which cannot tolerate any contamination.

Disadvantages of Diaphragm Valve

  • The weir may prevent full drainage of piping.
  • Working temperatures and pressures are limited by the diaphragm material. Generally, the pressures are limited to 200 psi (1380 kPa) and temperatures up to 400 F (204 C).
  • The diaphragm may also limit the hydrostatic pressure.
  • The diaphragm may experience erosion when used extensively in severe throttling service containing impurities.
  • Diaphragm valves are available in limited sizes, usually NPS ¹⁄₂ to 12 (DN 15 to 300).

Typical Application of Diaphragm Valves

  • Clean or dirty water and air service applications
  • De-mineralized water systems
  • Corrosive applications
  • Radwaste systems in nuclear facilities
  • Vacuum service
  • Food processing, pharmaceutical, and brewing systems