Ball Valves Types, Construction, Applications and Advantages

The ball valve (Fig. 1) is a quarter-turn valve suitable for clean gas, compressed air, and liquid service. They also can be used for slurry service, but provisions for prevention of crud buildup must be made. The use of soft-seat materials such as nylon, delrin, synthetic rubbers, and fluorinated polymers imparts excellent sealing ability. 

Fig. 1: Ball valve in closed position

With fluorinated polymer seats, ball valves can be used for service temperatures ranging from 450 to 500 F ( 270 to 260 C); with graphite seats, service temperatures to 1000 F (538 C) or even higher are possible. Also, with metal backing seats, the valves can be used in fire-safe services. Ball valves are similar to plug valves in operation. They are nonbinding and provide leak-tight closure. The valves exhibit negligible resistance to flow because of their smooth body and port.

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Jobs in Haji Mawarid International Petrochemical Dhahran, Saudi Arabia

JOB REF: HMIPRSA 966/21003

Client/employer: Haji Mawarid International Petrochemical  Dhahran, Saudi Arabia.

Recruitment agency: Haji Mawarid International Petrochemical  appointed Recruiter Mr. Owen Briggs.

At Haji Mawarid International Petrochemical  Dhahran, Saudi Arabia, specialize in all works for professionals engaged in Saudi Arabia interestingly we are recruiting new professional, but are keen to consider the right opportunity for the right people.

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Check Valves Types, Construction, Applications and Advantages

Check valves are designed to pass flow in one direction with minimum resistance and to prevent reverse or back flow with minimal leakage. The principal types of check valves used are the tee-pattern lift check, the swing check, the tilting-disc check, the Wye-pattern lift check, and the ball check, illustrated in Figs. A to E, respectively.

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Globe Valves Types, Construction, Applications and Advantages

Conventional globe valves may be used for isolation and throttling services. Although these valves exhibit slightly higher pressure drops than straight through valves (e.g., gate, plug, ball, etc.), they may be used where the pressure drop through the valve is not a controlling factor. 

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Gate Valve Types, Construction, Applications and Advantages

Gate valves are primarily designed to serve as isolation valves. In service, these valves generally are either fully open or fully closed. When fully open, the fluid or gas flows through the valve in a straight line with very little resistance. Gate valves should not be used in the regulation or throttling of flow because accurate control is not possible. Furthermore, high-flow velocity in partially opened valves may cause erosion of the discs and seating surfaces. Vibration may also result in chattering of the partially opened valve disc. An exception to the above are specially designed gate valves that are used for low-velocity throttling; for example, guillotine gate valves for pulp stock.

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PressFit Piping Systems Installation and Advantages

The Pressfit piping system is an innovative, rigid, self-restrained mechanical joining method for schedule 5 or lighter weight lightweight stainless steel and carbon steel pipe. This proprietary mechanical pipe joint is designed for use in small-bore piping systems, NPS ¹⁄₂ (DN15) to NPS 2 (DN50). The Pressfit system may be applied to any service that is compatible with the piping materials, the gasket material, and the temperature range of the system, unless prohibited by the manufacturer’s instructions.

Typical applications would include building-services piping, potable water, fire protection, heating and cooling, industrial processes, process cooling and heating systems, plant utilities, and vacuum systems.

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PreStressed Concrete Cylinder Pipe (PCCP) Installation Procedure

Pipe Handling and Storage

A crane or backhoe outfitted with a steel cable sling may be used to unload pipe unless the pipe has a special exterior coating that could be damaged by a steel cable sling. In such cases, a fabric sling should be used. Multiple slings are often used in handling large pipe and fittings. Pipe can be stored directly on the ground in nonfreezing conditions. If freezing conditions are expected, the pipe should be set on wooden timbers off the ground to prevent the pipe from becoming frozen to the ground. Rubber gaskets should be stored in a cool place, out of the sun, away from fuel oil, gasoline, electric motors, and any other environment that can damage rubber.

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PreStressed Concrete Cylinder Pipe (PCCP) Joints

Rubber O-ring Bell and Spigot Joint

(a) Lined cylinder pipe (LCP) and (b) embedded cylinder pipe (ECP) profiles

Figures A and B show a cross-section of the typical LCP and ECP bell and spigot joint. As can be seen, an O-ring rubber gasket is compressed into the spigot groove by the bell ring when assembled to form a water-tight seal. Portland cement grout is poured into a fabric band (diaper) by the installer to provide corrosion protection.

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PreStressed Concrete Cylinder Pipe (PCCP) Manufacturing Process

The AWWA standard C3014 provides a comprehensive description of the manufacturing requirements for pipe and fittings. The purchaser should require, in the specifications, that all pipe and fittings be manufactured per the AWWA C301 standard.

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Prestressed Concrete Cylinder Pipe (PCCP) Design

Design Parameters

PreStressed Concrete Cylinder Pipe (PCCP) is designed as a rigid structure to resist the simultaneous application of external loads and internal pressures. External dead loads normally encountered are earth loads, foundation loads, or surcharges applied at the ground surface. External live loads are caused by vehicular traffic, railroads, or construction equipment.

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Prestressed Concrete Cylinder Pipe (PCCP) Types

Prestressed concrete cylinder pipe consists of a structural, high-strength concrete core, a steel cylinder with steel joint rings welded at each end providing water tightness, steel prestressing wire, and a portland cement-rich mortar coating. Two types of PCCP are manufactured: lined cylinder pipe (LCP), which is detailed in Fig. A and embedded cylinder pipe (ECP), which is detailed in Fig. B.

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