In this guide we’ll walk you through everything there is to know about liquid dump 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 liquid dump valves.
Use the table of contents to skip to different sections of the learning path.
In this video, Product Manager Mike Fick demonstrates the operation of a Lever Operated Liquid Dump Valve. This valve is a reliable, emissions-free product designed to dump liquid from oil and gas production vessels such as separators, treaters, and free water knockouts.
A float inside a production vessel moves up and down based on the liquid level inside. This moves the lever on the Trunnion Assembly. This lever is mechanically linked to a lever on the Dump Valve by a linkage rod.
As the liquid level in the production vessel begins to rise, the float moves upward. This forces the trunnion lever downward. This pushes the valve lever down and opens the valve.
As the liquid level in the vessel begins to fall, the float moves downward, forcing the trunnion lever upward. This pulls the valve lever up and closes the valve.
There are two versions of this product. These are the Diaphragm Balanced and Piston Balanced Throttling. The illustration in the video shows the action of the Diaphragm Balanced version. This is a cost-effective version ideal for use in normal conditions.
The Piston Balanced Throttling model of the Dump Valve is an ideal option if your production conditions are more erosive. In this valve, the trim raises up out of the flow path when it opens. This limits its contact with the process fluid, thereby mitigating deterioration due to erosion.
Control valve damage is common with modern completion processes. Managing erosive production fluid is a constant battle for oil and gas producers, particularly during flowback.
Control valves take a beating from the sand and other particulates in the flow, often causing damage to the valve trim and body. This leads to unwanted downtime as your team has to repair or replace valves regularly.
We have been examining the damage patterns of valves used in erosive conditions and working on innovative solutions, like the Lever Operated PBT Valve, to help producers stay online longer.
We are now excited to introduce a new solution for these conditions: the Low Pressure High Volume Valve.
The Low Pressure High Volume Liquid Dump Valve is for oil and gas producers who want to extend production time through flowback and in erosive applications.
It provides long-lasting, robust control of low pressure applications that allows you to keep your well running longer.
The angle-body design creates a low-contact flow path for the fluid. When the valve is open, more volume can flow through the valve with less contact on the valve body than in the through-body valve design.
The inverted valve trim design means the trim is pulled entirely out of the flow path. This reduces the amount of contact between the erosive production fluid and the trim, limiting the potential for damage.
The open-yoke position indicator on this valve means you don't have to guess whether the valve is open or closed. Just like on our High Pressure Control Valve, you can clearly see the valve's position with a glance.
The Low Pressure High Volume Valve can be powered with pneumatic supply, or you can pair it with one of our electric actuators and reap the two key benefits of electric control: zero-emission operation and remote control.
With the pneumatic version, you can convert the topworks in the field from fail-closed or fail-open operation.
The Low Pressure High Volume valve is ideal for liquid dump applications on your oil and gas separator or free water knockout.
Pneumatically Operated Liquid Dump Valves, also referred to as balanced low pressure control valves, are available in two primary models—diaphragm balanced or piston balanced throttling.
These valves are used to dump liquid from separation vessels such as 2- and 3- phase separators, heater treaters and free water knockouts.
If you’re metering off the fluid, the snap action controls will give you the most accurate meter readings.
Another benefit to pneumatic controls is the ease of adjustment for fluid gravity changes, meaning that you won’t have to weight the float or adjust the lever arm and weights for any changes in the vessel.
This valve operates in conjunction with a pneumatic liquid level controller, such as the new Gen 3,* or a Pneumatic Liquid Level Switch, which senses the level of liquid inside the vessel.
The Gen II is shown in the video. Check out the all-new Gen 3!
When the liquid reaches a desired level, the controller sends a pneumatic signal to the valve.
The Diaphragm Balanced model is a cost-effective version, good for normal conditions.
The signal enters the actuator of the valve. An increase in the diaphragm pressure overcomes the spring force and moves the diaphragm assembly down. This opens the valve, allowing the liquid to be dumped downstream.
This valve is balanced, which means the downstream pressure creates a force from both the top and bottom to eliminate the effect of higher differential pressures.
When the liquid level recedes, the pneumatic signal is vented out through the level controller. This removes the pressure from the actuator, allowing the valve to close.
For erosive conditions, we recommend the Piston Balanced Throttling model. In this valve, the trim raises up out of the flow path to mitigate erosion.
In order to meet their emissions goals many producers are choosing to use compressed air for their pneumatic control valves and equipment.
Kimray has several solutions available to help you meet your company’s ESG goals utilizing compressed air, as well as electric actuators and pilots, non-vent control valves and more.
Lever Operated Liquid Dump Valves can be used on separators and knockouts to dump water or oil.
These valves are paired with our trunnion assemblies. The Trunnion Assembly is what connects with the float and float arm inside the vessel. Outside, the trunnion and the liquid dump valve are mechanically linked with a linkage rod.
Connections for liquid dump valves include threaded as well as flanged. We also have angled and through bodies in both versions, so they can fit a wide variety of connection sizes and types. Here are a couple of pictures of these dump valves in action.
On the left, you see the float going up and down with the liquid level inside a separator. This is just a two-phase separator separating gas from liquid. The float rises and falls with the changing liquid level, pushing the linkage arm up or down, opening and closing the dump valve.
Next we'll discuss interface control and liquid levels in two-phase separation (gas and water); these can also be used in three-phase separation (oil, water, gas).
The interface float must be weighted in a three-phase separator. This is because you want it to sink through the oil but only operate on the water, remaining buoyant in water but sinking through the oil. We have a step-by-step video on this process if you want to know how to weight a float.
The float inside the vessel often determines how much pressure you can put on it. Floats are normally the weakest point of this system other than the dump valve.
Be aware of the float you have and the operating pressure of that float. I've seen cases where floats have collapsed because the operating pressure of the vessel was too high. If a float collapses, it won't be buoyant, causing problems in controlling liquid level in your vessel.
The design on this dump valve below is the older style with the keyway on the shaft. The change was made to the Double D design for more contact area and rigidity, making repair easier. Watch: How the New Designed Hub and Shaft Reduce Rotational Play.
As flow comes into this diaphragm-balanced connection, it rests on the seat. These are balanced valves, meaning the downstream pressure is balanced both underneath the seat and on top of the diaphragm. This balance is communicated through the hollow stem.
Regardless of the pressure drop across the valve, the Lever Operated Liquid Dump valve can open and close more easily. As liquid level rises in the vessel, the linkage connecting the trunnion assembly to the dump valve will push down on the arm, engaging the stem and opening up the seat.
The soft seat design ensures a bubble-tight seal when the valve is closed.
Bubble-tight seal means a Class VI seal, where no bubbles can pass through. Unlike class four seals, such as metal-to-metal seats, which allow a certain amount of allowable leakage.
The soft seat provides a reliable seal, preventing leakage past the valve when closed. The flow is impeded by the seat, and if fighting abrasives, the seat is a point of wear that can wear out quickly.
The Delrin cage is used in the Diaphragm Balanced valve and is intentionally designed not to fit inside the Piston Balanced valve. Metal cages are used in Piston Balanced valves, and they don't have the Delrin material.
If you ever have problems fitting the cage inside the valve body, give us a call, and we can help you ensure you have the right components.
The Piston Balanced valve is similar to the Diaphragm Balanced valve but is rated for higher pressures.
Like the Diaphragm Balanced version, It's a balanced valve, so it's still taking downstream pressure and communicating it up above the piston through the hollow stem. But because it's a metal piston instead of a diaphragm, it can operate at higher pressures.
The flow path is different in the PBT, designed to move abrasives and parts up and out of the way. As liquid level increases in the vessel, the float rises, pushing down on the valve arm through the mechanical linkage. Instead of the seat opening down, the piston is pulled up out of the flow, preventing wear on both the trim and valve body.
This design allows higher volumes and better performance when abrasives are present in your fluid. The PBT has become the most popular option due to the constant presence of sand in most new production.
Trunnion assemblies are available in 6", 8", and 10". They connect directly to the production vessel.
These are flanged options and are rated up to 250 PSI. When choosing your trunnions, ensure they meet the operating pressures of your equipment.
The most popular is the 7x12" float, rated for 600 PSI. The size of the float affects the torque communicated to the valve, influencing its performance. Different floats are available for various needs.
Trying to figure out how much torque you need to close the valve? Good news—we have a torque calculator for that!
To use this calculator, plug in your specific conditions, such as float weight, buoyancy, rod length, lever lengths, and linkage rod placement to get your torque requirements. Proper sizing of valves for each application is crucial to avoid issues and ensure optimal performance.
A common mistake I see people make with these is that they oversize their valves.
Let's say you put a 3" valve on a vessel, but it's really low flow—less than 1,000 barrels a day. I see this all the time—people put 3" valves just about on everything, and they're almost always oversized.
And that leads to a couple of unwanted outcomes:
An oversized valve is going to be opening and closing very quickly. It's not going to be a smooth action, because it's oversized. As soon as that valve opens, the liquid level inside of the vessel is going to drop very quickly and so that valve is going to close immediately then it might open up quickly then close. This action will inevitably lead to premature wear on the valve body.
Large valves require more torque to move. If you see a valve that seems like it's sticking open or maybe sticking closed, you're not generating enough torque to operate that valve.
If you know if it's stuck closed and you go up and you just have to put a little bit of pressure on that arm and then it it springs open and and it won't close, or it springs open and springs shut, that's a a sign that the torque requirement is too great for your setup.
This means you need to adjust the linkage on the outside of the vessel. You can move the linkage on the trunnion side farther away from the fulcrum point or farther away from the vessel, and then on the valve side you'd be moving the linkage arm further away from the valve or closer into the vessel. Make sure to do this incrementally.
The adjusting packing on the Lever Operated Liquid Dump Valve provides an easy way to prevent leaks and make your valve last longer before maintenance is required.
However, it responds best to small adjustments. Typically, just an eighth of a turn can be enough to stop a leak without impeding valve operation.
There are two main types of pneumatically operated liquid dump valves:
Let's take a look at some of the features and troubleshooting tips for each.
The Low Pressure High Volume Valve has replaced the Piston Balanced Throttling version of the pneumatically operated dump valve.
The Diaphragm Balanced Liquid Dump Valve is named because the upstream and downstream pressure are balanced, above and below a diaphragm.
This is not the ideal valve for erosive conditions due to the flow path through the valve itself, which can cause premature wear on the valve seat, the cage, and the valve body. The seat opens down into the flow path, directing the fluid out to the edge of the valve body, which can cause washout around the valve body and the seat.
For standard liquid dump applications in non-erosive environments, as long as the flow requirements match the rated flow rate of the valve, the diaphragm balanced valve will work just fine.
The flow rate of the Low Pressure High Volume Valve (LPHV) is much higher than that of the diaphragm balanced dump valve due to the flow path through the valve.
Upstream pressure flows down through the seat, and when the valve opens, the entire plug assembly moves up and out of the flow path. This design increases flow capacity and reduces wear on the valve body. This makes it ideal for erosive applications, such as when there is sand in the production fluid.
The LPHV is a throttling dump valve. The actuator from our 1" high-pressure control valve, which has a larger surface area, allows for smoother operation and finer control. The ratio plug and flow characteristics of the valve also help with throttling action, allowing a larger volume of fluid to pass through the same 2" connection.
Both the Diaphragm Balanced and the LPHV Liquid Dump Valves can accept an outside pneumatic supply. If you are transitioning from natural gas to compressed air or nitrogen for pneumatic supply to reduce your emissions, these are compatible products.
Liquid Dump Valves Learning Path
Installation, Repairs & Conversions
