Some manufacturers provide specifically engineered fluid automation systems where ambient temperatures may reach as low as -40° F (-40° C). These devices are used with process valves in oil and gas, hydrocarbon, energy, refining, industrial heating, food and beverage, electricity, vehicle, and other applications.
Most ordinary models are only rated down to 32° F (0° C) for reliable operation. Fluid automation equipment must function efficiently during the long, chilly months, usually unattended and at remote locations, making repair or replacement more challenging. Refrigerated or cryogenic processing lines offer unique difficulties in terms of material flexibility and sealing integrity, even in warm regions.
Five Key Qualities
There are five essential characteristics to consider when buying valves, cylinders, and other fluid automation equipment for use in low ambient temperatures.
Reliability and Reputation
Dormancy, a lack of resilience/flexibility, and cold temperatures can negatively impact valve performance.
As temperatures drop, flexibility and resilience weaken. It is vital that the elastomer in the valve disc or diaphragm has a firm and resilient consistency in order to seal effectively against the valve seat.Elastomeric polymers shrink as they become colder and go through the glass transition, becoming rigid, brittle, and glass-like. These modifications stop the disc from conforming consistently to the seat, which allows a leak channel to develop.
When valves are used seldom, such as in low-cycling applications, dormancy results. A valve’s O-ring seals can stick against the ridges or flaws in the metal surface of its mating components when they are in continuous contact with the body or main spool for days or months. Then, after being used, it reacts slowly or not at all.
Both of these problems put the valve’s dependable operation in jeopardy. Surface friction can be reduced with simple assembly procedures, such as using high-grade lubricants that stay usable in the cold. High-quality valve suppliers carefully choose elastomers that withstand low temperatures to solve potential issues, and valve seals are designed to be optimal for arctic circumstances. Innovative construction techniques, such as swapping out old O-ring seals for new T-shaped seals with a significantly lower surface area at the point of contact, can almost eliminate dormancy.
Cylinders used in cold environments can experience similar problems to valves. Regarding resilience, cylinder seal elastomers may experience brittleness, shrinkage, and various rates of adjacent materials’ thermal expansion and contraction. This makes it possible for there to be leak paths. Therefore, manufacturers of cylinders minimize gap tolerances in their designs and choose specific cold-tested O-ring and seal materials that can maintain adequate flexibility at low temperatures to reduce these dangers.
Similar dormancy issues that affect valves may also affect cylinders utilized in freezing temperatures. Stick and sliding points may arise for surfaces that come into prolonged contact. Advanced types may be permanently lubricated during assembly with properly chosen low-temperature lubricants to reduce friction and combat dormancy. Additionally, manufacturers may use unique structures like spring-energized lip seals on crucial dynamic parts like rod and piston seals.
Can a specific valve perform at -40° F (-40° C) consistently, safely, and reliably in your application?
The following chart, for instance, displays comparable UL and CSA testing specifications for general-purpose and safety shutdown valves. In addition, both organizations conduct endurance, valve seat, and exterior leakage testing.
After meeting these minimal agency testing requirements, suppliers can undertake additional tests not mandated by the agency. For instance, they might do thousands of different endurance testing cycles. To more accurately imitate real-world operating conditions, further thermal testing may involve cycles at high and low ambient temperatures, as well as in saturated settings when the temperature of the valve and the air media sent through the valve are all kept at -40° F (-40° C) for extended periods.
Breadth and Depth of Offering
Many consumers prefer restricting their supplier choices to businesses that provide the most excellent variety of low-temperature products. As a result, some multinational corporations now specify certain low-ambient-temperature valves from a single source—and use them solely for a given application, even in warmer regions—to combine inventory or to meet global specifications.
Low Temperature and Low Power
The need for valves and other devices that can operate at cold temperatures has been accompanied by a corresponding rise in the demand for low-power devices. Users may value cheaper energy prices. More importantly, traditional valves may need heat tracing or protection in remote locations like oil and gas transmission pipelines or extraction sites. These and other power requirements frequently call for more significant, expensive power sources, including solar panels or battery charging systems. As a result, several providers have produced versions that satisfy low temperatures and power requirements.
In addition to devices that always use the least amount of current feasible, some more recent models use peak-and-hold technology, which typically draws 11 watts (W) immediately upon opening before continuing to operate at 0.5 W or 1 W. Any well-optimized valve for low power may allow customers to specify smaller battery banks, run the valve for extended periods without sunlight, or ensure that backup generators and batteries aren’t overworked.
Service and Support
It’s essential to consider much more than just the hardware when choosing the best source for low-ambient-temperature valves. It can be as crucial to finding a partner who has the availability and support systems you require. Look for straightforward and simple-to-use ordering and catalog materials. OEM designers greatly benefit from the ability of some vendors to download 2D drawings and 3D models directly into their CAD software.
Investigate difficulties with the response, and whenever you can, ask distributors about their connections to particular valve manufacturers.
The first important factor to consider is availability. When you require a specific fluid automation device, you frequently need it immediately. Unfortunately, a lot of users complain that availability has recently deteriorated significantly. Make sure the supplier you choose can offer quick delivery and convenient local stocking, ideally through a quick-shipment program with high on-time delivery rates.
It can be challenging to choose fluid automation equipment for use in low ambient temperatures. Critical aspects such as reliability, testing, compliance, options, low power consumption capability and support must be closely considered by users, designers and other specifiers.However, solutions that provide dependable performance in colder regions of the planet for years to come are the result.