Pneumatic fitting evolution
Historically, the materials used for fittings were brass and stainless steel. With the evolution of new surface treatment techniques and alloys their performance has improved.
For example, it is possible to have variations of 303 or 316L stainless steel to form a fitting; The nickel-plating of brass has made it possible to increase the number of applications where they can be used.
Today, in addition to this traditional offer, ranges of technical polymer fittings have been developed thus expanding the possible fitting solutions.
Seal materials have also developed to satisfy the demands for transporting different fluids (air, water, grease, oil, ...). Ensuring the sealing of the system, the seal must definitely be compatible with the fluid conveyed and the environment of the operating system. The multitude of materials allows, once again, to increase the possibilities of use and performance, especially over time.
Connection with the other elements of the system (mainly tubes) is another important point to consider. Gripping technologies have evolved for retaining the tube, you can now choose between four main techniques:
- Collet or gripping ring for push-in fittings,
- Barb fittings or compression for universal fittings.
Each system has its advantages and limitations dependent on the specific application.
All these developments have made it possible to provide more efficient pneumatic fittings, meeting the more demanding physical requirements and more aggressive environments.
Therefore, the multiplication of possible products has made the selection step essential and strategic in order to optimize the installation. The issue arising now for the system designer is: how to select the best product for their system?
What are the criteria to consider before making your choice?
Each person has their preferences and experiences to help decide which product will be most appropriate to meet their requirement. Nevertheless, certain rules remain universal and inevitable to avoid fundamental errors.
Six points of consideration form a basis for the selection of a low pressure fitting:
- The application environment
By environment, we have to understand the atmospheric conditions in which the fitting is going to be used. But also air quality, room temperature, chemical-splash or contact (cleaning fluids, ...), the risk of shock, particles (sparks, chips, ...), etc.
- Conditions of use & performance
This point concerns what the user expects from the product. What are the requirements in terms of pressure, temperature, flow, vibration and other physical stresses that the fitting must resist during operation? And of course, the sealing performance is an essential parameter to consider.
- Nature of the fluid to be conveyed
Essential for compatibility reasons and because it must not damage the fitting (o-ring, body, ...), the nature of the fluid must be known with precision, especially when it is a liquid, with additives.
- Other components in the system
A fitting is part of a set of components that will build up a circuit. Tubes, valves, couplers, blowguns and others components must meet the same characteristics as the fitting. A component can’t be dissociated from the circuit, both technically and in terms of physical performance.
- Regulations and market specifications
Some areas of application or particular applications are regulated by legal and operating rules (food, medical, ...). These directives and regulations must be taken into consideration.
- Manufacturer quality and services
Do not forget the supplier of the product. Are they the manufacturer? What are his delivery times? Does he work at a national, or international level? What are his options for problem-solving, for the supply of replacement or additional/replacement parts long after the system in manufactured? What quality systems does he have in place (ISO 9001, ISO/TS 16949 etc), What follow-up capabilities can he offer?
The choice of the manufacturer will have a significant impact on the product quality and services.
Choosing your industrial fitting
By taking one by one the criteria as stated above and following them, you will find, for sure, the optimal product for your requirement.
To complete this presentation, we recommend you download our white paper "6 Expert Tips on How to Choose Your Pneumatic Fitting!" in which each criteria is considered and detailed to help you design, install or carry out maintenance of your pneumatic circuit.
This blog post was contributed by Erwann Evin, PMC product data specialist, Parker Hannifin Division Fluid System Connector Europe