Valves are the gateway to controlling any flow of gas or liquid around a system used in a lot of industries.
Choosing the correct valve and control system for your business may seem like a simple decision that involves purchasing a ready-made solution straight from the shelf. However, there are a lot of mitigating factors which complicate this choice, many of which stem from the unique problems posed by the very industry that you operate in.
Valve Deconstruction
Whether a valve is used to control direction, pressure, the speed of a flow rate or as a method of shutting down a system, the build and design of all valves comprise of the same set of ingredients, which are:
Within these separate components, the internal elements of the valve are the parts which suffer the greatest amount of stress due to the working conditions that they operate under. As moving parts are in regular contact with frictional forces, high-pressure environments and sometimes corrosive materials, they suffer wear and tear at a heightened rate to the other parts which make up a valve.
But it’s not just the main elements within these constructions that need to be carefully observed and maintained. The stem, seat, and plugs inside any valve can all be easily identified and are a primary focus of any routine maintenance schedule within a company, however, these parts are not the only critical components that require due care and attention.
The Unsung Heroes
The supporting cast is just as critical as the main stars when it comes to the world of engineering. Valves are finely-tuned pieces of equipment and as such, everything within them plays a key function in the holistic process and output of the device.
As a result of the many uses, fluids characteristics, operating conditions and environments that a valve can be subjected to operate with, there are many variations to the number of designs which exist today. This, in turn, creates a large number of these lesser, incidental parts which subsist across the whole valve spectrum, but some of the generic elements which are used between multiple designs include:
- Locknuts
- Center Bolt / Studs
- Guide Pins
- Lift Washers
- Springs
- Spring Plates
- Guide Rings
- O-Rings
- Gaskets
These parts play two common roles within the functionality of a valve, to hold the larger internals in place or contribute to their movement, and to seal the internal section of the valve from the exterior and maintain a closed-system environment.
Fixtures and Fittings
The fittings used to hold the valve together are clearly complicit with the structural integrity of a valve’s design. Yet often they’re disregarded as an afterthought when it comes to rebuilding or repairing a valve in a working system.
With the wide range of uses that a valve can serve, manufacturers can find it hard to provide a fully conclusive set of guidelines for each component that they produce, and therefore it is the engineer’s role to ensure that the device and parts thereof are suitable for the task at hand. This includes the type of material that is used, whether that’s a metal, plastic, resin or any other applicable material.
Needing to withstand the pressures temperatures and stresses that will be repeatedly asked of them throughout their lifecycle, much of this will depend upon the specific use that is required of them. Another factor to consider is how often you intend to dismantle the valve as although some fittings allow for removal and reuse, other bolts are designed for a single use which would be inappropriate if your maintenance schedule requires frequent stripping and cleaning of the valve.
Much of this can be pinned on the industry that they’re employed in, as the accuracy levels required as well as the conditions of operation will greatly depend upon the goal of the business itself. Whereas a valve used in the food and beverage industry must be hygienically sound in every aspect, a similar valve part used in a petrochemical application will likely require non-reactive characteristics.
Hermetical Seals
Likewise, the difference between controlling the fluid flowrate of a gas and a liquid presents a similar problem with the seals that are used in the design.
As gas has an inerrant ability to escape any high-pressure system, the valve can often be the weakest link within a system due to the moving parts involved and the bottle-neck of pressure which can build in this area. Meanwhile, liquids are much easier to control in this regard as they’re composed of larger molecules and the signs of a leak are much more visible to visual checks by mechanics.
This difference between hydraulic and pneumatic systems also has a much more nuanced variation between similar liquid types used across different industries. For instance, a valve essentially connects two parts of a system together and due to the nature of the valves role, there could also be a pressure difference between these two sections. A double-block and bleed (DBB) valve is able to seal the pressure from both sides of this connect while a double isolation and bleed (DIB) generally only seals one side from high pressure.
Similar to this, the seals and types of packing used in valves alter across different industries. With many solutions available, from oil seals, to dry and multibarrier seals to complimentary seals, there are many factors to consider when building a design and most of these are industry driven, due to the nature of the operation which dictates the requirements.
Peripheral Valve Internals for You
While engineers and suppliers who specialize in working within your given industry is a good starting point, knowing the demands your operation poses to your equipment is also the most solid first step.
To know the answer to any problem, you must first understand the question and even the smallest of components within a valve can make a huge difference to the final outcome. While the peripheral internals may seem like just that, incidental parts of little consequence in the grander scheme of your business, choosing high-quality products is a must for overall durability and these peripheral internals hold the key to the functionality of a component.
This is especially true within the more high-stress, repetitious tasks, such as an industry which uses PET compressors, but every industry has its own specific demands. By identifying these, you will take a large step towards finding a cost-effective solution that can be tailored to achieve higher performance.