List of Valves Which are Use in the Oil & Gas Industry

WHAT IS A VALVE?

Valve types used in the petrochemical industry are suitable for the following applications: We are the leading valve supplier in Morocco.

• Fluids (hydrocarbons, oil, gas, steam, water, acids) can be started or stopped using valves (e.g. gate valves, ball valves, butterfly valves, knife gate valves, and plug valves).
• Control the flow of fluid through the pipeline (example: globe valve)
• Fluid flow can be controlled (control valve)
• A 3-way ball valve, for example, can change the flow direction.
• Reduce the pressure of a process (pressure reducing valve)
• Check valves to prevent back pressures (safety valves) or overpressures (pressure relief valves) in a piping system or device (pump, motor, tank).
• To protect equipment from damage caused by solid parts (y and basket strainers) filters debris flowing through pipelines.

VALVES BY TYPE OF ACTUATION

• MANUAL: lever, wheel, and/or gears are used to operate the valve; The valve is operated by electromechanical devices, or actuators, which may be electric, pneumatic, hydraulic, or gas-over-oil.

VALVE BY DESIGN

• GATE VALVE: This type is the most commonly used for piping and pipelines. A gate valve is a linear motion device used to regulate the flow of a fluid (a shutoff valve). For throttling applications, such as regulating fluid flow, gate valves cannot be used (globe or ball valves should be used instead). Consequently, gate valves can either be fully opened or fully closed (by manual wheels, gears, electric, pneumatic, or hydraulic actuators).
• GLOBAL VALVE: This type of valve throttles (regulates) the flow of fluid. Gate valves are preferred for this function, as globe valves can also shut off the flow. As the fluid passes through a non-linear passageway, a globe valve causes a pressure drop in the pipeline.
• Check valves prevent backflow from damaging downstream apparatus such as pumps, compressors, etc., by preventing backflow in the piping system. Opening the valve when the fluid is at sufficient pressure, prevents unwanted flows by closing it when the fluid returns at a design pressure (reverse flow).
• BALL VALVE: Ball valves are quarter-turn valves used for shut-off applications. By rotating a ball inside the valve body, the valve opens and closes the flow of fluid. The ball valve serves similar purposes to gate valves, but is lighter and more compact, making it the industry standard for on-off applications. There are two main designs: floating and trunnion (side entry or top entry).
• A butterfly valve is a versatile and cost-effective valve for modulating or opening and closing fluid flows. As a result of their simpler construction and lower costs, butterfly valves are becoming more and more competitive with ball valves due to their concentric or eccentric designs (double/triple).
• PUSH VALVES: This type of linear motion valve is used for throttling and shut-off applications in piping systems handling solid materials, slurries, and dense fluids.  The flow of a pinch valve is regulated by a pinch tube.
• PLUG VALVE: A plug valve is a quarter-turn valve used for shutoff systems. Water pipelines were controlled by plug valves introduced by the Romans.
• In piping systems, safety valves protect against dangerous overpressure that may threaten human life or other assets. As soon as a set value is exceeded, a safety valve releases the pressure.
• Petrochemical control valves are used to automate complex processes.
• Although not a valve, Y-strainers filter debris and protect downstream equipment that might otherwise be damaged.

VALVE SIZES

To ensure that valves of various manufacturers are interchangeable, ASME B16.10 specifies the face-to-face dimensions (i.e. the distance between the inlet and outlet of the valve) of the key types of valves.

Also, read “Butterfly Valves: Parts, Advantage, Working Process & Operation”

ASME B16.34: VALVE COMPLIANCE

Oil and gas valves are designed, manufactured, and tested according to ASME valve standard B16.34. This standard is also mentioned in the more general ASME specification ASME B31.1, “Power Piping Design”.

It was modified in 1988 to include threaded-end and weld-end valves alongside flanged-end valves.

For a valve to comply with ASME B16.34, the following conditions must be met:

• Material standards for chemistry and strength for valve bodies & shells are ASME and ASTM
• Heat treatment ensures grain structure, corrosion resistance, and hardness of the body and shell materials.
• ASME B16.34 specifies minimum wall thicknesses for each pressure class for bodies and other pressure-containing components.
• ASME B1.20.1 and ASME B16.11 cover NPT and SW end connections.
• Internally loaded stems prevent blowouts.
• The bolts will be ASTM grade with maximum applied stress controlled by B16.34.
• Shell tests are conducted on each valve at 1,5x the rated pressure for a specific period.
• For a specific test time duration, each valve is tested for seat leakage in both directions.
• The materials of construction, operating limits, and manufacturer’s name are permanently tagged on each valve.

Aira Euro Automation is the leading valve supplier in Morocco. We offer various types of industrial valves like ball valves, butterfly valves, control valves, pressure-reducing valves, and many more.

CONTROL VALVES

According to signals managed by a controller, a control valve regulates the flow rate of fluid along a pipeline or process (as well as related parameters like pressure, temperature, and level).  To ensure the process works as intended and produces the desired output in terms of quantity, quality, and timeline, flow control valves play a crucial role in complex petrochemical processes. 

Due to increasing process automation in most industries, flow control valves using more frequently in recent years.

Water treatment plants, oil and gas plants, power generation, fire prevention systems, and food processing industries use these types of valves to streamline processes and provide greater safety to personnel and equipment.

There are several types of flow control valves in use oil and gas industry, including globe, butterfly, and ball valves. Compared to other types of actuators, air-operated actuators require less ancillary equipment (such as cabling, and switchgear).

A combination of an electronic controller, a positioner, and the actuator of the valve (which can be electric, pneumatic, or hydraulic) opens and closes the valve.

In response to changes in key process parameters, such as pressure, level, temperature, and flow, the actuator opens and closes the control valve.

As a result, the process parameters maintain within the requir target range to make sure the process, as a whole, works as intended and produces the end product in the desired quantity and quality.

FLOW CONTROL VALVE COMPONENTS

The main components of a control valve are:

• Modulating elements contain and operate within the valve body
• The positioner is the element that controls the degree of valve opening and mounts on the valve body
• In valves, actuators use to move the modulating elements, such as the ball (ball valves), the disc (butterfly valves), or the stem (globe valves).
• It controls by.

FLOW CONTROL VALVE ACTUATORS

Actuators selecte base on the thrust required by a rod and the movement of a valve.

Engineers need to determine whether the diagram actuator or piston actuator is the most suitable type. Flow control elements move and position within valve bodies using actuators as the primary energy source.

Pneumatics, electrics, hydraulics, electro-hydraulics, and manuals are all available. In throttling applications, pneumatic actuators most commonly use.

Pneumatic actuators have been the standard for automatic control for more than a century. There are three types: piston, spring-and-diaphragm, and rotary vane. Both the first two can use on both rotary and sliding-stem valves; the latter can only use on rotary valves.

FLOW CONTROL VALVE ACCESSORIES

Positioners, transducers, boosters, solenoid valves, limit switches, handwheels, travel stops, snubbers, regulators, and transmission lines, normally select according engineering specifications.

Material selection heavily influences the cost.

In addition to material costs per pound, fabrication and inspection costs contribute to the uninstalled cost of the valve. In addition to the cost of installation, the installed cost includes the cost of any damage caused by improper installation and the cost of the inspection.

The latter involves analyzing the chemistry of the material, radiographic and surface examinations of castings and welds, and ensuring the valve installed is the correct one and oriented properly.

Choosing the most appropriate or optimal control valve type depends on the particular study of the pipe system and its fluid condition, but the size of the control valve should be such that it drops pressure through it rather than the drop in pressure of the pipe.

ANSI / FCI leakage standards apply to all valves, including steam control valves. There is a relationship between the number of leaks and the permissible internal leakage rate.

Valve Class I has the highest internal leakage rate and is usually the cheapest, while valve Class VI has the lowest internal leakage rate. To maintain a long service life, steam control valves must have a leak rate of at least Class IV.

FLOW CONTROL VALVES TYPES

Depending on how the stem moves, control valves can divide into two main types:

Globes (straight, angle, 3-way), diaphragms, and pinch control valves are linear motion/reciprocating valves

Types of rotary stem valves include ball, butterfly, and plug valves

There are two types of globe control valves: single-seat and double-seat.

CONTROL VALVE SELECTION

Choosing the correct control valve requires consideration of many factors. These are the general criteria to consider for selection:

• Various types of control; varying degrees of control; varying degrees of shutoff.
• The design temperature, the design pressure, and the allowable pressure drop.
• A fluid’s corrosivity, erosion properties, and other characteristics such as fouling or coking.
• A valve’s inherent characteristics include its leakage hazard, its thermal conservation, and its price.

After knowing the design criteria, process engineers can select the correct type of control valve and related equipment, as well as the valve’s material.

A detailed specification (usually drafted by a piping engineer) and a purchase specification describing the valve for suppliers are the next steps.

As a minimum, the specification should contain a description of the type of control valve (rotary, sliding); the bore size and pressure rating; end connections; type of body joints; material specifications for body components, trim, gaskets, and bolts; positioner and controller requirements; and a reference to industry design standards for valve types.

Generally, engineers use a computerized system to determine the most suitable valve and its features based on the parameters of the process.

CONTROL VALVES INSTALLATION

• At least one pipe diameter should add to the discharge steam line piping. It is not uncommon for discharge piping to expand at least two or three pipe diameters. By expanding the pipe, the valve outlet velocities reduce, thus prolonging the valve’s life. Following the control valve, the valve manufacturer will provide the appropriate pipe size. Heat transfer inlet connections should size according to the pipe size.
• Heat transfer inlet connections should be at least ten pipe diameters away from the steam control valve. Before changing flow direction in pressure reduction applications, at least 20 horizontal pipe diameters must be left.
• Whenever possible, the control valve should install horizontally, not vertically.
• In low flow operating conditions, it is more important to select the valve properly than in high flow operating conditions.
• Control valves must install with bypass valves. As a result of a valve failure or maintenance, the facility’s personnel can operate the process without the control valve.
• Real-time line diagnostics are possible by installing pressure gauges before and after the steam control valve. There can be no overstatement of the importance of proper installation. It is common for a control valve to be improperly install causing a troublesome startup. A person with an instrumentation background should supervise the installation and setup of control valves at the very least.