How to Select the Right Pressure Regulator for Your Application

So, when a regulator isn’t operating optimally, that will affect the customer’s end process. It could affect production, the quality of their end product, or purge times. Ultimately, a downstream component could fail due to inconsistent pressures in the system. If a regulator is not functioning correctly, then, in most cases, it will not make the flow the customer needs, or it may make the flow but at a different pressure.

The things that I need to do first when a customer is having an issue with a regulator are to show that we’re here and to respond quickly by having a meeting or discussion with them. The objective of the meeting or discussion is to gather detailed information from customers on exactly what the issue is, what the application is, and what the requirements are, such as inlet pressure, outlet pressure, and flow. I want to get as much information as I can from them, specifically where the regulator is being used, how it’s being used, and what the expected operation of the regulator is. That helps me get a better picture of what potentially is not happening correctly.

The most common issue we see in the field with pressure regulators is creep. What creep means is that, as the regulator is trying to shut off flow and the system is no longer being used, that valve is going to contact the regulator’s seat and try to create a seal. Creep occurs when that seal is not fully created, and there is still some leakage from the high-pressure side of a regulator to the low-pressure side. This can be really problematic and dangerous if the downstream components are not rated for the high pressure that could be creeping across the seat. It’s one of the most common things we see with pressure regulators. Most often, it’s attributed to some sort of debris, dirt, or damage on the seat. Luckily, it’s pretty easy to fix, but we need to make sure that we diagnose that this is what’s going on.

In terms of things that can go wrong, there are typically two primary reasons for a problem with a regulator: either the original regulator hasn’t been properly sized and selected, or, quite often, we see issues with contamination impacting a regulator. That usually, or often, happens when the regulator is first installed and during the commissioning process. Dirt and debris are left in the line, and the regulator functions with this very fine gap between the seat and the poppet. Any debris that gets into that gap can cause the regulator to malfunction. Contamination will cause a seat leak, so gas will flow across the seat when it really should not be flowing and should be closed.

Another common issue we see as customers are using pressure regulators is the supply pressure effect. The supply pressure effect is something you see while a regulator is in operation. It is likely working as it should, but it’s a counterintuitive behavior of pressure regulators. As your inlet pressure falls, as it would very often if you’re feeding from a cylinder and you use that gas, the pressure is going to decrease. As that inlet pressure falls, your outlet pressure will have a tendency to rise, which, for many customers, sends up an alarm bell that there is something wrong with this regulator. In fact, that’s the physics of how regulators work, and it’s normal behavior. There are things that we can do in terms of selecting different properties in the regulator, components, or configurations to minimize the supply pressure effect if it’s required for those applications.

Our field engineers have deep technical knowledge of regulator function and troubleshooting, so they can help customers diagnose just what might be going wrong with those pressure regulators. Ultimately, what’s impactful to a customer, and what the customer doesn’t realize, is that when they are looking for a regulator, it’s more than just a single component. They want it to work fluidly with the rest of their system, and a lot of times, they don’t consider what effect that component will have on the rest of the system, whether it’s a valve, a gauge, or a technician who has to use that system. The regulator is just a piece of that puzzle, and taking a more holistic look at it really allows us to more safely provide them a solution to their need.

Your primary types are pressure-reducing regulators and back-pressure regulators. Those are the main two applications, but there are a lot of other styles that can be fine-tuned based on the application. Pressure-reducing regulators do just as the name says: they reduce a high pressure to a low pressure. This is traditionally what people think about when they think about pressure regulators. A less common but still frequently used type of pressure regulator is a back-pressure regulator. That regulator controls an upstream pressure, so it controls what’s behind it. These regulators are very often used when a minimum upstream pressure needs to be maintained through a system or where very fine overpressure control is needed. Specific to those styles, you have vaporizing regulators and changeover regulators. You can have higher sensitivity by having larger diaphragms, and then, from a loading standpoint, you have dome-loaded versus spring-loaded options.

Swagelok has two main series of regulators: the K Series and the RHPS Series. The K Series is usually used for analytical instrumentation applications, and the RHPS Series is mainly used for process applications. The smaller K Series regulators are typically used in analytical systems and labs. We also have gas distribution panels, which use the smaller K Series regulators. We also have the KEV electrical vaporizing regulator, which is used in labs to vaporize samples.

The other family of regulators that we supply is the RHPS regulators, and those are predominantly used more in process applications. That can be anything from food and drink applications to driving fire suppression systems. We have them in refrigeration systems, really any process that has a flow that needs pressure regulation. We have other regulators for tank blanketing and pharmaceutical applications. We have a lot of interest and use in compressed natural gas around the world. Recently, we’ve certainly seen an uptick in interest in regulators for hydrogen applications, and I suppose that’s part of the move toward sustainable energy.

Regulator selection is really important in order to achieve the performance you want in your system or your process. The whole idea of the regulator is to provide that consistency so the process can function optimally. Our field engineers can help customers find the right configuration, sized properly for their application, so they’ll have the best performance suited to their application.