The Effects of Design on Service Life
As mentioned in other articles, eliminating all negative factors affecting "economic life" and "safe use" is possible by combining the right materials with a good design.
Now let's examine the effects of two different design philosophies applied to service regulators on "safety" and "economic life." Because "safe" and "economic" use are interconnected concepts.
C.1. Eliminating High Pressure Risks Through Design
As we have discussed in detail in other articles, risks arising from high pressure constitute the most important "safety" and "life" problem for the regulator.
The area of the parts of the regulator exposed to high pressure should be minimized as much as possible through design; if this is not possible, additional measures should be taken to reduce long-term leakage risks. Below are the first-stage designs of 2 different products (Figure 1 and Figure 2).
In the equivalent product design shown in Figure 2, the inlet pressure enters directly into the regulator, acting on the plastic parts and the large SSV surface or the cover surface in its place.
In the Gazkon design shown in Figure 1, however, the inlet pressure is reduced to 300 mbar before entering the regulator, while still inside the inlet connection. As a natural consequence, the risk of "high pressure" transfer to the outlet side is completely eliminated, offering "safe" operation. Furthermore, since no pressure load is applied to the 1st stage cover and screws, it eliminates the need for "service" by preventing leaks and other risks over time. This is the most important factor for a "long economic lifespan".
Another design problem is seen in the pressure balancing system of the 1st stage regulation shaft. As shown in the product below, the 1st stage shaft is balanced by the "inlet" pressure taken behind it. In this system, as the inlet pressure increases, the first stage shaft is pushed in the opening direction. Therefore, especially if it is subjected to the "mains surge pressure" mentioned in section 1.1.2, it risks failing to close properly and transmitting the inlet pressure to the outlet. For this reason, service regulators containing this type of regulation system must be equipped with a "SSV" safety unit (Figure 3). As is commonly the case on the market, using such products without the SSV involves extremely dangerous risks.
Figure 3. Standard product with added SSV unit
On the other hand, Figure 1 shows how this risk is eliminated with "correct" design. Since the 1st stage shaft is balanced by a "lever" system, the inlet pressure is not taken into the regulator. At the same time, since the 1st stage shaft moves with the pressure, the increasing inlet pressure completely locks the regulator inlet, stopping the high line pressure that could cause "network accident pressure" at the regulator inlet. In this system, since the 1st stage regulation does not contain a moving "O-ring", it will not cause any internal leakage and will guarantee a "long economic life".
C.2. Prevention of Corrosion Risks through Design
The effects of external corrosion, mentioned in section 2.1 of this study, can be eliminated with correct design, in addition to the material, to mitigate its impact on "economic life".
In the design below, the Stage 1 cover is also a part that carries the internal pressure. Therefore, it must not corrode. Even a localized thinning or perforation will lead to external leaks.
However, if a Stage 1 cover design that does not come into contact with the gas is used, as in the design in Figure 1, even if the cover corrodes, there is no possibility of any external leakage, etc. This is a factor that will extend the "economic service life".
C.3. Eliminating Internal Leakage Risks Through Design
In addition to the safety risk it creates, internal leakage in the regulator also reduces the "economic service life" by triggering safety equipment, thus requiring "service". Therefore, what is important is not eliminating the internal leakage risk with safety equipment such as an SSV, but completely eliminating the internal leakage risk through design. Thus, since there will be no need for service, a "long economic life" is ensured.
Looking at the two different designs in Figure 1 and Figure 3 from this perspective, it can be seen that the SSV design in Figure 3 has signal channels that can cause pressure to pass to the outlet or movable O-rings that can leak if they malfunction. This is why an SSV unit has been added to eliminate the risk.
On the other hand, in the design shown in Figure 1, there are no signal channels or leaking O-rings, etc., that carry the inlet pressure to the outlet. At the same time, since there is no moving O-ring system, there is no risk of internal leakage. Therefore, there is no need for an SSV. This eliminates the need for servicing, offering the user safe use with a "long economic lifespan."
Recommendations for Users
In summary, from the above explanations, it is clear that for a regulator to be used "safely" and with a "long economic lifespan," it must be designed with the right philosophy and using the right materials, going beyond the usual designs and patterns.
The copycat products we are accustomed to today are not actually very suitable in terms of "safe" and "long-lasting" use. Similarly, the SSV-based regulator approach, which initially sounds correct, is clearly not a "safe" and "long-lasting" economic solution, especially for service regulators.
Our company's most important mission is to utilize the experience we have gained over the past 30 years, understanding the conditions and usage needs of our country, to benefit this sector. Based on this mission, our greatest desire is that this study, prepared with the aim of contributing to our sector, will benefit gas distribution companies and provide an economic gain for our country.