Understanding Severe Service Problems.
15% of valves are responsible for 85% of valve problems in any given industrial plant; and using the wrong valve in a severe service application can lead to costly premature failures.
Severe service applications vary in degree of severity, so without over-engineering, Trimteck offers its customers timely, cost-effective products to enhance performance while driving down operating costs.
Our rationale is simple: invest in a reasonably-priced custom-engineered solution and enjoy extended performance combined with a dramatic reduction in operation and maintenance costs caused by failures and untimely shutdowns.
Severe Service
Featured Severe Service Solutions
At Trimteck, we are obsessed with quality.
Browse from our selection of engineered solutions for your Severe Service applications below. Click a product to read full details and documentation.
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Severe ServiceST-1™ Single Stage Anti Cavitation Trim Cartridge
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Severe ServiceST-2™ Multi Stage Trim Anti Cavitation Cartridges
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Severe ServiceST-3™ Noise Abatement Valve Trim
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Severe ServiceST-3D™ Noise Plate
Attenuation Diffuser -
Severe ServiceST-3P™ Diffuser Plate
Noise Abatement Device -
Severe ServiceST-4™ Stacked Disc Valve Trim
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Severe ServiceST-5™ Flashing Valve Seat for Venturi Flashing Service
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Severe ServiceCVD-5B™ Abrasion Resistance Metal Hardening
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Severe ServiceGuardMaster Metal Bellows Seal
Severe Service
Solution Information
What Constitutes a Problem Valve?
In general, there are three major categories of problems that can be predicted and addressed while sizing and specifying a control valve.
1
Cavitation & Flashing
- Excessive Fluid Energy Along Flow Path
- Inadequacies in Actuation System
- Pressure Drop
2
Noise &
Vibration
- Velocity
- Flow Rate
- Trim Selection
- Seat Leakage
- Consistency & Composition of Fluid
- Time of Exposure
3
Corrosion & Erosion
- Consistency & Composition of Fluid
- Incorrect Material Selection
Background: Fluid Flow & Pressure Recovery
Cavitation Explained
Cavitation and flashing in control valves occur only with liquid media, and the principal factors responsible are fluid velocity and pressure drop.
If upstream pressure is just above the vapor pressure, then the pressure may drop below the vapor pressure as the fluid flows through the valve.
Cavitation will occur if the pressure recovers downstream of the valve to a pressure that is once again above the vapor pressure.
Background: Cavitating & Flashing Flow
Cavitation Damage
Cavitation damage is a form of hyper-erosion that can destroy both control valves and piping, which can result in unacceptable process failures.
The vapor bubbles created as a result of a pressure drop will implode – nucleate, grow, collapse, and rebound – as the vapor returns to liquid form.
The implosion of vapor bubbles in the cavitation phenomenon inflicts damage in the form of small pits in the metal, which cumulatively wear away surfaces.
Noise & Vibration Explained
As pressure drop is taken in a control valve, most of the resultant energy is lost as heat and the remainder is converted to noise.
In liquid applications, both cavitation and flashing tend to cause hydrodynamic noise, however, in gaseous applications – gas or steam – a sudden pressure drop and high velocity cause turbulence that results in aerodynamic noise.
Aerodynamic noise is a problem not only because of the noise pollution and possible damage to people within earshot, but because it indicates that there is turbulence and vibration in the valve and the downstream piping, which can cause physical damage to equipment.
Factors Affecting Cavitation and Noise
Cavitation and noise do not always cause damage, but when they do they depend largely on the following factors:
- Pressure Drop: the higher the pressure the drop, the greater the chance of damage as a result of noise and cavitation.
- Time of Exposure: the longer cavitation or noise occurs in an area, the more likely it is to result in damage
- Materials: hardened materials reduce damage and extend the life of the trim and/or valve. For noise, thicker and larger diameter pipelines and valve bodies help in abatement.
- Flow Rate: both cavitation and noise tend to increase with increasing flow rates.
- Valve and Trim Design: Trimteck produces anti-cavitation and anti-noise trim to counteract the effects of cavitation and abate noise.
- Seat Leakage: if leakage occurs through the seat of the valve while it is closed, the fluid escapes from a high-pressure area to a low-pressure area, which can exacerbate cavitation and noise. Trimteck’s Optimux® control valves achieve ANSI Class V metal-to-metal seat leakage, which minimizes seat leakage.
- Fluid: behavior, specific gravity, and viscosity of fluid need to be considered when selecting Trimteck valves and trim.
OpGL® Trim – Flow Characteristics
Each valve has a flow characteristic, which describes the relationship between the valve coefficient (CV) and the valve stroke – as a valve opens, the flow characteristic—which is inherent to the design of the selected valve—allows a certain amount of flow through the valve at a particular percentage of the stroke, which allows the valve to control the flow in a predictable manner.
The three most common types of flow characteristics are equal percentage, linear, and quick-open.
Two rules of thumb for choosing the right flow characteristic:
1. If most of the pressure drop is taken through the valve and the upstream pressure is constant, a linear characteristic will provide better control.
2. If the piping and downstream equipment cause significant resistance to the system, equal percentage will provide better control.
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Trim Materials
Valve parts – body, bonnet, bonnet bolting, plug, ball, disk, wedge, and/or drainage plug – exposed to pressure, process fluid, corrosion, and other effects of the service are required by regulation to be manufactured from approved metals.
In applications requiring elevated material hardness levels and resistance to corrosion and abrasion, Trimteck has pioneered the use of CVD-5B.
Generic Requirements for Valve Selection
The first step in combating severe service applications is selecting the correct valve for the service.
- Valve Coefficient
- Flow Characteristic
- Rangeability
- Shutoff/Leakage Class
- Body Materials & Style
- Trim Materials & Design
- Soft Goods Materials
Specific Requirements for Severe Service Valve Selection
The next steps in combating severe service applications is to control for the following elements:
1
Cavitation & Flashing
- Control Velocity:– Liquids: Inlet shouldn’t exceed 60 ft/s (18 m/s); Outlet shouldn’t exceed 100 ft/s (30 m/s)
– Gases: Trim exit shouldn’t exceed head velocity of 70 psi (480 kPa)
2
Noise & Vibration
- Stage Pressure Reduction
- Reduce Noise to 85 dBa at 3 ft (1m) from the valve (un-insulated)
- Ensure appropriate material selection
3
Corrosion & Erosion
- Examine Fluid Composition
- Ensure appropriate material selection
More Information
Read our full documentation on Severe Service.
What differentiates Trimteck from other manufacturers?
Organizational Differentiators
- Fast/Responsive
- Agile
- Consultative Quoting
- Control Valve Experts
- Experienced
- Robust & Modern Manufacturing Capabilities
- Made in USA
- Engineering Expertise
– Applications
– Design
– Simulation
Product Differentiators
- Reliable
- Robust
- Better/More Precise Control
- Broad Products/Solutions Portfolio
- Specific Technical Attributes for the range of service conditions:
– General
– Special
– Severe
PROUDLY SERVING OUR CUSTOMERS WORLDWIDE
Control Valves
How to order Control Valves for Severe Service from Trimteck
This website provides thorough coverage to assist customers in making informed choices for their facility's process control requirements.
If you need help don't hesitate to reach out to us. Thank you for your interest in our products!
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Contact Trimteck
- Use our Find a Rep to locate a Trimteck authorized distributor
- Or contact Trimteck to speak with a sales engineer 954-753-5545
- Email us:
[email protected]
[email protected]
[email protected]
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Submit your specifications
- Utilize our full Online Valve Specification Form
- Or request access to our Accuvalve Valve Sizing Specification software
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