In this guide we’ll walk you through everything there is to know about high pressure control valves.
From the basics of how it works to step-by-step repairs and troubleshooting, you’ll gain a solid foundation of knowledge on how to operate and maintain Kimray’s high pressure control valves.
Use the table of contents to skip to different sections of the learning path.
A pneumatic High Pressure Control Valve is a versatile device producers use to control a variety of liquids and gasses.
There are four key parts of this control valve that are typically required for it to operate correctly:
Our standard buildup for a High Pressure Control Valve package is going to include all four of these pieces. However, if you are building this package up yourself or repurposing a valve for a different application, you may not need all of these.
If you already have dry supply gas on location that you can pull from another regulator, you may not need a supply gas regulator or drip pot.
If the working pressure of the pilot is higher than the valve's working pressure, you don't need a sense line protector. The potential for the pilot to be over-pressured isn't there because the pressure on the valve itself isn't going to exceed the working pressure of the pilot. Let's look at two examples to explain this:
To speak with an expert about building your High Pressure Control Valve Package, contact your local Kimray store or authorized distributor. We can help you repurpose valves and tell you what components you're going to need for your application.
High Pressure Control Valve trim consists of three basic parts:
These are the operative parts that control the flow of liquid and gas through a valve. They are also the parts most exposed to process elements, and therefore most vulnerable to wear over time.
There are three primary types of control valve trim:
Below, we'll outline the specific operation and typical applications for each control valve type.
A valve trim’s flow characteristic is the relationship between the percentage of flow and the percentage of valve stem travel between 0% and 100%.
Snap Valve Trim opens quickly and is used for on/off service.
Primary applications include liquid dump, pressure relief, and metering. We also offer zirconia seats for erosive applications.
Nominal valve trim is used for throttling liquids, liquid level control, and in applications where water hammering has been an issue.
Equal percentage valve trim is used to control pressure or flow of gases and vapors in throttling applications.
In oil and gas applications with highly abrasive conditions, control valves take a real beating.
Sand, salt, and other abrasive elements wear away the internal trim, packing, and body as it moves through the valve. Sources of valve abrasion include flowback, natural sand in the formation, and saltwater.
Wear and abrasion resistance is critical to optimal performance of oil and gas control valves. The premature wear abrasion causes to standard trim in control valves can cost you thousands in repairs and replacement valves, not to mention downtime. Therefore, choosing the right type of valve trim for your environment is key.
Kimray offers two High Pressure Control Valve trim materials designed to perform well in erosive conditions. These materials are harder than our standard trim and don’t wash out as fast.
Carbide is a hard metal we recommend using for valve trim during flowback. In an ASTM G65 test of material loss, Carbide trim performed 2.5x better than standard D2 Steel trim.
Kimray’s wear-resistant Zirconia Trim is designed specifically for highly abrasive oil and gas applications. Zirconia offers a combination of abrasion and corrosion resistance not found in steels, alloys, or many forms of other ceramics and carbides.
Zirconia is a robust, hard ceramic material. It outperforms metal trim materials in abrasion resistance. This is an ideal solution for high-sand areas like North Texas, Australia, India, and China.
Zirconia is superior to Stellite and other metals for two reasons:
In an ASTM G65 Sand Abrasion Test of material loss, Zirconia outperformed 316 Stainless Steel and Stellite.
The chart above shows the results of this test. It measures material loss based in cubic millimeters (mm3).
Kimray’s Magnesia Stabilized Zirconia valve trim performed 10 times better than Stellite Alloy and nearly 90 times better than 316 Stainless Steel. Kimray Tungsten Carbide also performed better than other metals.
Valve trim performance can be affected by more than just valve abrasion. Extremely high temperatures compromise metals like Stellite. Zirconia Trim is an ideal solution for operation in extreme temperatures.
This trim is designed to perform at temperatures ranging from -200°C to 850°C. Stellite, meanwhile, is only tested for temperatures between 315°C– 600°C. And because Zirconia is not a metal, it’s not subject to NACE.
Kimray’s Zirconia Trim combats valve abrasion more effectively than any choice on the market. That keeps your valves up and running, and your well site reaching its peak performance.
Recently a producer in the Woodford Shale contacted us with a problem.
They had been using Kimray High Pressure Control Valves for years, but had begun to burn through a lot of trim sets in the valves, replacing them more often than expected. We began asking questions.
Q: What have you been ordering?
A: High Pressure Control Valve packages for all new construction
Q: What type of trim are you requesting on these valves?
A: 5/8" equal percentage trim
Q: What are the temperatures and flow rates of your wells?
A: Conditions differ depending on the well
This was a problem we were prepared for.
Conditions are rarely the same well to well in the various locations and applications where Kimray customers operate. Because of this, we offer different types of valve trim designed to handle different temperatures, pressures, flow rates, and process fluids.
In this case, the equal percentage trim this customer was using was designed primarily for gas applications, where precise throttling is ideal.
Their new wells, however, were flowing liquid, and bringing a lot of sand to the surface along with it. Because they were using equal percentage trim, the valve was consistently open, subjecting the trim to the abrasive, sandy flow path. This was the central reason for the premature wear.
We advised the customer that carbide snap trim for these valves would be a better option. This would give them a harder ball and seat, and the snap trim opens and closes quickly, so it would be exposed to the abrasive flow less often and therefore last longer.
We also helped the customer resize their valves accordingly to the appropriate flow rates of the wells. Because our trim can be field converted, they didn’t have to order new valves, just outfit their existing ones with the new, better suited trim.
To speak with an expert about finding the trim set that best fit your flow conditions, contact your local Kimray store or authorized distributor.
Control valves are designed to throttle, but they are also often expected to provide some type of shut-off capability.
A control valve's ability to shut off has to do with many factors: Balanced or unbalanced plug, seat material, actuator thrust, pressure drop, and the type of fluid can all play a part in how well a particular control valve shuts off.
There are actually six different seat leakage classifications as defined by ANSI/FCI 70-2-1976.
But you will likely be concerned with just two of them: Class IV and Class VI.
Class IV is also known as a "Metal-to-Metal" seat classification. It is the kind of leakage rate you can expect from a valve with a metal plug and metal seat.
All Kimray High Pressure Control Valves with metal-to-metal seats are Class IV.
Class VI is known as a "Soft Seat" classification. Soft Seat Valves are those where either the plug or seat or both are made from some kind of composition material such as Nitrile or Polyurethane.
All Kimray valves and regulators with resilient seats are Class VI.
| Leakage Class | Allowable Leakage | Valve Types |
|---|---|---|
| Class IV | 0.01% of rated valve capacity | Intended for single-port valves with metal-to-metal seats |
| Class VI | The test fluid is air or Nitrogen. Pressure is the lesser of 50 psig or operating pressure. The leakage limit depends on valve size and ranges from 0.15 to 4.00 ml. per minute for valve sizes 1 through 6 inches. | Intended for resilient-seated valves |
The chart below shows the calculations of allowable leakage for Class VI valves at port diameters 1"-6" on, using the standard measurements of ml per minute and bubbles per minute.
| Port Diameter | ml per minute | bubbles per minute |
|---|---|---|
| 1 | 0.15 | 1 |
| 2 | 0.45 | 3 |
| 3 | 0.90 | 6 |
| 4 | 1.70 | 11 |
| 6 | 4.00 | 27 |
Correct valve sizing is crucial to proper operation of your oil and gas production site. Today I’ll be discussing tips on valve sizing and sharing 3 symptoms of an improperly sized control valve.
Typically, symptoms of an undersized valve are easy to spot. When you start production, the valve will stand wide open and your safety relief valves will go off due to over pressuring. If you’re in a liquid dump application, your vessels will also begin overfilling with fluid.
Symptoms of an oversized valve are often more subtle. Many of the calls I receive are from customers who did not realize their valve was oversized until a major secondary issue occurred on their site.
Here are 3 symptoms you have an oversized control valve:
If your control valve seems to be unstable or erratic and the valve is opening and closing constantly, a likely cause is that the valve is oversized. This means the valve is trying to find your set point, but because it is too large it is unable to precisely meet your desired flow or pressure set point. Though it continues to try, it can’t help but overcorrect, shutting, then opening, then shutting again.
The second symptom is water hammering. This can happen in oil or gas applications when a control valve is oversized. What you’ll see is the valve closing violently, which can lead to a stretching and eventual compromise of the valve stem. Over time water hammering also stresses the coupling block and valve seat to the point of breaking.
Again, an oversized valve will result in a high stroke count, which over time will wear down your valve trim and packing much faster than it should under normal operation. This can lead to deterioration of the trim, resulting in poor performance and potential environmental issues.
Over time, the conditions and flow characteristic of any well are going to change. This may be due to production slowing on an aging well, fracking of an existing well, or secondary recovery efforts. At this point it is important to reassess your control valve sizing to make sure the valves are sized appropriately for the new flow conditions.
Use these quick tips to make sure your control valves are sized correctly and production is operating at maximum capacity.
Despite how it sounds, "valve failure" does not always mean that the control valve itself has failed. In the event of power or pressure loss, a Kimray High Pressure Control Valve Actuator will cause the control valve to "fail", or stop, in one of two positions:
Today we will look at what these two failure modes mean.
Power to a valve can be interrupted for a number of reasons. Some common reasons include:
The term “power” here refers to the means by which the actuator is moved, be that air pressure, gas pressure, or electric power.
At some point, your well site will experience one of these power-loss events, and if you haven’t planned for them, they can wreak havoc on your production processes and equipment.
In order to prevent this, it is important to carefully consider the fail position of your control valves.
Fail Open (FO) means that when there is a loss of signal, the valve opens.
If you are using your valve in a back pressure application, such as holding pressure on a separator, a fail open valve would allow you to prevent excessive pressure build up on the upstream side of the valve in the event of a failure.
Fail Closed (FC) means that when the signal is lost, the valve closes.
If you are using your valve in a pressure reducing application, such as suction control on an air compressor, a fail-closed valve would help protect any downstream equipment from excessive pressure in the event of a failure.
No matter which failure mode is selected, always ensure your system includes the proper safety valves to prevent overpressure.
It depends on the valve. On a Kimray High Pressure Control Valve, there is a position indicator attached to the stem that shows if the valve is open or closed.
Another way to tell if your control valve is fail open or fail closed is to look at the breather plug.
A threaded valve is secured to piping by threads. It may also be called a screwed-end valve or NPT, which stands for National Pipe Thread. NPT connections are tapered, so as you thread your valve onto the pipe, the connection between valve and pipe gets tighter.
All Kimray threaded valves are NPT, but NPS, or National Pipe Straight, is another end connection type. Be aware that while NPT & NPS threads will engage and seem like they fit, they will not seal properly with each other and result in leaks.
Yes! When making the connection between pipe and valve, thread tape or pipe dope help make a good seal to ensure the process fluid stays inside the valve and piping where it belongs.
Something else to consider is that at some point you will likely have to change the valve or piping.
Over time threads tend to gall and stick together, especially if you’re using stainless-steel threads.
When that time comes, you will be glad you used thread tape, because it resists this metal-to-metal sticking and makes it it much easier to break the connection.
A flange valve connection is a type of connection that uses a gasket between the flanges of a valve and pipe to seal the joint. It is secured with bolts, and if installed correctly, flange connections create a fluid-tight seal.
These connections are straightforward and make it easy to install and remove valve from from any application.
Producers typically use flange valve connections on valves 3" and larger.
Kimray utilizes two categories of flanged valves—raised face (RF) and ring-type Joint (RTJ).
On raised face flanged valves, the gasket surface is raised above the bolting circle face.
This flange face is the most common type in the oil and gas industry and is available in all pressure classes and in most pressure and temperature ratings. This connection uses a semi- or non-metallic gasket.
A ring-type joint flanged valve will have a similar raised gasket face but also with a ring groove machined into the face for a steel or hard metal ring gasket. RTJ flanges are typically used for more severe applications with very high pressures, and/or high temperature systems.
Both flange faces are secured with bolts, and if installed correctly they create a fluid-tight seal. Flanged connections are straightforward and make it easy to install and remove your valve from any application.
All Kimray valves with flanged connections are either RF or RTJ. However, there are other flange faces such as flat face flange (FF), lap joint flange, male-and-female flange (M&F), and tongue-and-groove flange (T&G).
The connection surfaces on flanged valves have a serration to them that is important for holding a gasket in place while the valve is connected to piping and installed, thus minimizing the risk of leakage.
Until recently, Kimray painted this surface along with the rest of the valve body, and customers had to use a wire brush to clean the paint off the connection surface before installing.
The new nylon adhesive rings add value by covering that connection before the valve is painted. Customer can now simply peel off the adhesive ring and install the product.
The adhesive also comes with a VCI anti-corrosion additive that will provide additional protection for this serrated surface of the flanged valve.
It is critical to know the rating of what pressure your valve is for before putting it in line. Using an unfamiliar valve can be dangerous for you, your coworkers, and anyone else who visits the site.
Flanged valve ratings are based on the ANSI Pressure Rating System. ANSI—which stands for American National Standards Institute—is the body that establishes the measurement standards in the United States.
Valves rated at different ANSI classes react differently as the pressure and/or temperature of the process fluid changes.
This chart below converts valve ANSI ratings to PSI:
| Class | Carbon Steel | Stainless Steel |
|---|---|---|
| 150 | 285 psi | 275 psi |
| 300 | 740 psi | 720 psi |
| 600 | 1480 psi | 1440 psi |
| 900 | 2200 psi | 2160 psi |
| 1500 | 3705 psi | 3600 psi |
Should you use threaded or flange valve connection types?
It is usually the size of the valve and cost considerations that dictate this.
Producers typically use threaded valve connections on 1” and 2" valves because they are more cost-effective than flanged valves.
However, threaded valves must also be spun onto the pipe, and the weight of a 3" or larger valve makes this installation difficult.
Some producers use hoists to install larger NPT valves, but often they will choose to use flange connections if the valves are 3" or larger.
