For a regulator with a long "economic service life," using the "right" materials is of paramount importance. Now, let's examine how to make the "right" material selections for specific structural parts of the regulator.
B.1. Housing and Covers
The housing and covers that enclose the regulation stages are the parts of the regulator that carry pressure and external mechanical loads, and are also most severely exposed to environmental factors. Therefore, material selection here is crucial. Standards allow the use of many materials. However, for structural and economic reasons, housings and covers are manufactured from aluminum alloys and ZAMAK alloys. Both materials can yield good results with the right use.
However, aluminum requires more corrosion protection than ZAMAK. Therefore, painting aluminum regulators with "electrostatic powder coating" is a factor that increases their "economic life."
On the other hand, if the outer covers are directly exposed to gas pressure, we mentioned the need for extra protection in the corrosion section of our other article. Therefore, protecting regulators with this type of design with "paint" is essential for a long "economic life" and safe use. For pressureless cover designs like the one in the image on the right, this risk does not exist, and therefore extra protection with "paint" will not be necessary.
B.2. Springs
The most important components ensuring the stability of the regulator's outlet pressure and maintaining it throughout its "economic life" are the springs. Therefore, the choice of spring material is crucial for a long "economic life."
Springs made of spring steel can be protected for a certain period by a coating. However, this type of protection can disappear very quickly depending on the quality and thickness of the coating and the environment it is exposed to. Springs exposed to moisture, in particular, lose their coating within a few years, becoming "bare" and "unprotected." As a result, corrosion rapidly reduces their thickness. This prevents the regulator from providing the necessary pressure and flow rate, leading to malfunctions.
For these reasons, for a long "economic life" and stable regulation pressure, springs made of "stainless" material should be used.
B.3. Plastic Parts
For economic reasons, it is possible to make some parts of regulators from plastic. However, the use of plastic parts should be restricted, carefully considering their impact on "safe" use and long "economic lifespan."
It must be taken into account that plastic parts undergo changes in their mechanical properties with temperature. This, especially when combined with high pressure, poses a high risk in terms of "safety" and "service life." Therefore, plastic should "absolutely" not be used in the manufacture of parts involved in regulation and safety. Plastic parts should also not be used in areas exposed to gas or differential pressure. Threads should not be cut into plastic parts. Because micro-cracks formed during this process can cause the part to break or crack over time and lead to leaks.
On the other hand, it should not be forgotten that in the event of a fire in a service box due to an accident, regulators with melted internal parts can cause gas to escape or leak out of the regulator body.
In short, for safe and long-lasting use, plastic parts can be used in a very limited area, for example, as support plates for diaphragms on the atmospheric pressure side. Any other uses will not be "safe" and long-lasting.
B.4. Parts Involved in Closing and Regulation
One of the most important elements of "economic longevity" is ensuring that the "outlet pressure" remains within a certain range. Material selection is crucial here as well. Considering the effects of internal corrosion on materials, essential parts involved in regulation, such as "orifices," "plugs," and "safety plugs," must be made of stainless and wear-resistant materials. MS58 brass is the ideal material for this. While it's possible to make these parts from "ZAMAK" or aluminum for cost advantage, these are not suitable for long-term use. This point is specifically emphasized in many international and national specifications (e.g., IGDAŞ).