High Temperature Ball Valve
High Temperature Ball Valve
※ Size Range: 1/2″-24″
※ Class Range: 150LB-2500LB
※ Fire Safe Design
※ Anti Static
※ Anti blow-out
※ High Temperature Ball Valve Manufacturer
For the design, construction, and inspection of valves, working temperature is a critical component that should be considered. A high-temperature valve is one that operates at or above 425°C, although it might be challenging to tell the temperature range a high temperature valve operates in .
These valves include high temperature ball valves, globe valves, check valves, butterfly valves, and high temperature gate valves, however, high temperature ball valves are the most popular among these. Electric power, metallurgy, chemical fertilizer, and petrochemical sectors all often employ high temperature ball valves. According to ASME B16.34, the material of the valve body and internal section differs depending on the temperature range. It is important to design and identify the high temp level of the ball valve in order to assure the valve is in line with its corresponding high temp operating circumstances technically and logically.
According to the temperature classification and technical support, some high temperature ball valve manufacturers classify high temperature valves into five groups. Among them, valves for temperatures up to 800° C depend primarily on the selection of suitable materials to ensure their performance, whereas valves for temperatures above 800° C require the adoption of special designs, such as insulation lining or cooling arrangements, in addition to material selection. When designing high-temperature ball valves, it’s important to keep in mind that the material can only be used at temperatures that are no higher than specified limits.
High Temperature Ball valves for use in different operations are discussed in this article along with their design and characteristics. When specifying ball valves, end users can use this knowledge in coordination with manufacturers.
What is a High Temperature Ball Valve?
In several industrial manufacturing systems, ball valves that can resist and function in high-temperature operations are key components. High-temperature ball valves must be precisely developed and thoughtfully constructed, with each component requiring careful material selection, specific treatments, and extensive coatings to obtain the mechanical strength necessary to counteract the negative effects of thermal expansions. High-temperature ball valves can be distinguished by the valve seat sealing ring’s construction, which consists of several stainless steel sheets arranged on each side of a flexible sealing ring. These valves are also known as metal seated valves.
Metal-seated valves are made for corrosive and abrasive environments or for environments where the use of resilient materials is prohibited due to elevated temperatures. Metal-to-metal interaction between the ball and the seat rings produces the sitting mechanism. Hard metals like stainless steel are typically used to make seating faces as mentioned above.
When compared to standard soft seated valves, the fundamental advantage of metal-seated valves is their capacity to tolerate high temperatures and harsh operating conditions. Metal seats are capable of withstanding high temperatures, extreme cavitation levels from operation with abrasive applications, and fluid and hydraulic stress. They could be used in extremely corrosive situations as well. With the use of tungsten carbide, chromium carbide, and ultrasonic coating, metal seats may be toughened. The different design and material options guarantee that each application may meet the required performance criteria.
High temperature ball valves have an ISO-certified direct mounting pad cast on the top in case automation is needed, but they can also be operated manually. These valves can be operated by an electric, pneumatic, or hydraulic controller. The traditional quarter-turn design of these valves provides total control over the process medium flowing through. When fully opened, they offer free flow, and when fully closed, they have no leakage. Whenever applicable, they may also be employed with positioners to modulate, which enables the ball valves to be employed in throttling flow for particular purposes. If the control loop needs an L or T shape, the ball valve can additionally offer a multi-port option, giving the operator the choice of cutting off any or all of the connections.
High temperature ball valves are the highest quality performance control valves that are utilized in a variety of process control operations. The oil, gas, automobile, chemical, treatment, power, pharmaceutical, cosmetic, beverage, and food sectors, to mention a few, all employ these valves.
Working: High Temperature Ball Valve.
A high temperature ball valve is an emergency stop valve that regulates the flow of a liquid or gas using a rotating ball with a bore. The medium can pass through or is stopped by turning the ball 90 degrees around its axis. They are recognized for a longer service life and offer consistent sealing throughout their lifespan, also where the valve is not used for an extended period of time. They are therefore more widely used as a shutoff valve than, say, a gate valve. Many other varieties of industrial valves are less resistant to polluted medium than ball valves.
Ball valves can also be utilized as control valves in specialized variants. Due to the comparatively poor precision of flow rate control compared to other types of control valves, this application is less popular. However, the valve also has certain benefits in this situation. For instance, it still guarantees a trustworthy seal even when the medium is contaminated.
Construction: High Temperature Ball Valve.
A ball valve is constructed from a combination of several valve parts, including a body, bonnet, ball, stem, lever, valve seat, etc. We will attempt to cover those parts that are specialized for high temperature ball valves in this section. Trim elements in the valve assembly need to be strong enough to tolerate extreme temperature & pressure in addition to being compatible with the fluid.
- Stem: The majority of the torque needed to operate a valve is applied to the valve stem, thus it should be constructed of corrosion-resistant material with a high yield point and torsional rigidity even at high temperatures, such as Inconel, stainless steel, or Nitronic.
To reduce stem leaks and increase the comfort of use, the shape and surface quality of the stem is essential. Our valve stem design is ASME B16.34 and API 6D compliant and can withstand at least twice the valve’s normal torque. The stem is created to be “blowout-proof” in order to address a significant safety hazard. At the stem’s base, a specific chamfer is machined so that, in the case of a fire, the stem is forced upward and engages with the valve body on metal-to-metal contact. For low and medium torque loads, as well as for high cycle operations or high torque loads, a variety of stem materials are provided, including austenitic stainless steel, nickel alloys, and titanium.
- Seat: High temperature ball valves can only have a metal-to-metal seal since the ball and seats are in the flow stream. With metal seats, a tight shutdown is more difficult to achieve than with soft seals. The fit of components, surface coatings, and contact stress that delivers the required shutdown without harming the coating must all be under control in order to maintain a leak-free junction between the ball and seats. An excessive amount of seat leakage will happen if the design is unable to meet these standards.
- Bearings: Metal bearings, especially those made of stainless steel, are frequently coated to lessen wear and friction. The contact stress between the stem and bearings should be decreased to help slow down the rate of wear. At high temperatures, some materials, including duplex and precipitation-hardened stainless steels, can become brittle. Due to its exceptional erosion/corrosion endurance and high-temperature strength, ceramic trim and linings may be employed in harsh applications.
- Stem Packing: Designing seals is difficult since most polymers and elastomers cannot be used over 204°C. Despite its drawbacks, graphite has become the standard for the majority of high-temperature seals. Expansion, consolidation, and/or oxidation of graphite stem packing can result in early seal leakage. In oxidizing conditions, the packing set’s temperature should be kept to a maximum of 454°C, while in non-oxidizing services like steam, it should be kept to a maximum of 649°C. The use of bonnet and stem expansions and/or lantern rings, both of which act as insulators, can keep the packing rings below this limit. As a general rule, collaboration with a packing ring supplier should be included for every refining application exceeding 426°C.
Trim Coating: High Temperature Ball Valve.
The useable life of different trim components can be increased by hardening their outside surfaces. Surface coating is the application of a new substance to the body’s exterior layer. Several of the more popular hardening techniques include:
- Chromium Carbide (Cr3C2 ): A 0.3 mm tough outer layer is formed by applying chromium carbide with a nickel-chrome binder using a high-velocity oxygen fuel (HVOF). High-strength steels that have a chromium carbide coating on them have a micro-hardness of up to 68HRC. This coating can withstand high temperatures of up to 815 °C and cryogenic temperatures of -196 °C. This multifunctional wear-resistant coating is widely employed in hot catalyst handling, refining, and power-generating industries. Its corrosive limits are in moist sulfur or chloride conditions when sulfuric acid can develop and damage the coating.
- Tungsten Carbide: Tungsten Carbide with a cobalt binder coating is deposited using HVOF procedures. In order to achieve microhardness that exceeds 72HRC, this coating is primarily applied on 400 series martensitic stainless steel. This coating can withstand high temperatures of 538 °C and cryogenic temperatures of -196 °C.
- Hard Chrome Plating: It is advised to use hard chrome plating at temperatures up to 427°C. It may be applied at high operating temperatures, but as the temperature rises above 427°C, its hardness decreases. According to the results of laboratory experiments, chromium plating begins to lose half of its hardness when the temperature approaches 649°C. For chromium plating, a hardness of around 65 HRC is anticipated.
- Stellite: With exceptional corrosion resistance at temperatures up to 538 °C, a cobalt-based stellite coating also offers outstanding mechanical wear resistance. By using a Plasma Thermal Arc (PTA) technique, the stellite is placed. The majority of stellite alloys are cobalt-based and contain nickel, tungsten, carbon, chromium, and chromium (Ni). Stellite 6 is widely utilized in the pulp and paper sector as well as in refinery operations such as handling catalysts and hydrocrackers.
- Nitriding: It is possible to case-harden metal by nitriding. Contrary to other hardening methods, the base metal is not coated with a substance. With nitriding, the component’s outer surface is hardened, and as one penetrates further into the part, the hardness declines. Parts that have been nitrided may withstand temperatures of up to 816°C.
Note: The stability of the base material and how it is applied have an impact on the coating’s overall quality. As a result, a coating should be tested to determine its performance. Wear testing at different temperature are one approach to do this.
Features: High Temperature Ball Valve.
- Fire Safe: Since flexible graphite is also heat resistant, it is used for gland packing and flange gaskets, which ensure that no portion of the valve will be harmed by extremely hot surroundings. Hard graphite or metal seats are also exceptionally heat resistant. The supply of an anti-static device is also not necessary due to the electric conductivity between the components.
- Easy Maintenance: The valve body’s split body configuration makes maintenance simple and convenient, which is essential when working with slurries and other viscous fluids.
- High Flow Efficiency: As the line flow passes through the valve bore, the full port design delivers a maximum and normalized flow characteristic with the least amount of pressure loss. This is a crucial design requirement, especially for the trouble-free operation of viscous fluids like slurries.
Applications: High Temperature Ball Valve.
The separation of crude oil into refined products and consumable oils during petroleum refining involves several high-temperature procedures. Despite the fact that applications keep moving toward greater temperatures, high-temperature valves are nothing new to the industry. The trunnion and floating high temperature ball valves, on the other hand, are employed more commonly because of their flow efficiency and small form factors.
Additionally, hundreds of condensate drain valves and vents with temperatures above 538 °C may be necessary for a steam power plant in a refinery. In essence, full-port ball valves are preferred for these applications since ASME TDP-1 stipulates that drain valves must have a minimum flow area that is 85% of the surrounding pipe.
Summary: High Temperature Ball Valve.
Engineered ball valves are utilized in many refinery operations because they can operate at high temperatures without the need for elastomers or polymers. When a comprehensive strategy is used in the design phase, including the choice of materials, actuation, and accessories, these valves can function well. Even with careful consideration of these aspects, a developer must test and validate performance because of how serious these applications are.
The knowledge offered in this article could be used by end users to enhance their selection of high temperature ball valves and vendors when they specify and buy these kinds of valves.