What is a Weight-Operated Dump Valve?
The Kimray Weight-Operated Dump Valve (also known as a Treater Valve) is a weight-operated throttling valve designed to hold liquid level in production vessels such as heater treaters, free water knockouts, and saltwater disposal systems.
How the Weight-Operated Dump Valve Works in Liquid Level Control
The Weight-Operated Dump Valve actuates based on the hydrostatic pressure. Production vessels like heater treaters create a column of liquid in the discharge piping, which generates the hydrostatic pressure. Here's how the Weight-Operated Dump Valve works:
- First, a weight and lever push down on the diaphragm assembly. This closes the seat.
- When the liquid rises above the set level, it overcomes the force of the weight.
- The force of the weight lifts the diaphragm assembly against the weight load. This opens the valve.
- Liquid discharges and the column of liquid lowers.
- Lastly, the weight closes the valve.
One of the most beneficial features of the Weight-Operated Dump Valve is the balanced upstream/downstream pressure. This provides security for instances where pressure comes backwards from a tank up into the downstream outlet of the valve.
A Look Inside the Weight-Operated Dump Valve
Here's what's happening inside the valve as it operates:
The Vessel Gas Pressure (Red) inside the Upper Housing acts upwardly on the Balancing Diaphragm to cancel the downward pressure on the Seat.
Downstream Pressure (Blue) acting on the Seat communicates to the top side of the Balancing Diaphragm. This cancels any downstream pressure or vacuum effect on the valve operation.
A weight and lever—through a rotary Teflon-packed stuffing box to a Pivot Stem—is the force that holds the seat close. The Pivot Stem pushes down on the Diaphragm Assembly. When the liquid rises in the discharge piping of the vessel above the set level, it lifts the Diaphragm Assembly against the Weight load to open the valve. As liquid discharges to lower the level, the Weight closes the valve.
Adjusting the Weight-Operated Dump Valve for Liquid Level
You can field adjust the height of the water column by moving the weight on the attached lever in or out. The standard lever is designed to hold between two and four feet of liquid.
You can hold higher liquid levels by using an optional longer lever and adding an additional weight.
Watch this demo video showing how these work:
The Critical Importance of the Equalizing Line
You must install a gas equalizing line in pressurized vessels such as as treaters and free water knockouts. This line equalizes the vessel pressure and valve pressure, ensuring proper operation of the valve.
The gas equalizing line must be taken directly from the vessel. If the equalizing line is not pulled from the vessel but from a volume pot used for other controllers, the Weight-Operated Dump Valve will not hold a steady pressure and operation will be affected.
Likewise, if the equalizing line is shared with any other components, like a pilot, operation will be affected, and the valve may not open or close at the set liquid height.
It is also critical to make sure there are no sags in horizontal runs of the equalizing line, as these sags can fill with condensate or water and adversely affect the valve's operation.
Troubleshooting the Weight-Operated Dump Valve
Experiencing operational issues with your Kimray Weight-Operated Dump Valve? In this video, we explain three possible reasons for this and show you how to correct them.
If your Weight-Operated Dump Valve is opening and closing too quickly or not holding tight level control, this usually indicates an issue with the valve equalizing line.
Here are three things to check:
- If there are sections of your equalizing line tubing that droop, liquids can collect there and affect the accuracy of your equalizing gas to the Weight-Operated Dump Valve. This is especially true in cold weather, when the liquids can freeze. The fix for this is to run your tubing on a consistent decline all the way to the drip pot on the Weight-Operated Dump Valve. This will allow all of the liquids to drain out. Remember to drain the drip pot daily, especially in cold weather.
- Your equalizing line may be tubed up too close to the back pressure valve on your gas line. When the back pressure valve opens to release pressure from the vessel, it creates a slight difference between the actual vessel pressure and what the equalizing line is sensing close to the back pressure valve. The fix for this is to run your Weight-Operated Dump Valve equalizing line to a place on your vessel that isn't as subject to the abrupt pressure change.
- Your burner valve may be pulling gas from the Weight-Operated Dump Valve's equalizing line. When the burner valve opens, it sends gas into the burner to increase temperature. When this happens, it can rob gas from your equalizing line and create a difference between the actual vessel pressure and what the equalizing line is sensing. The fix for this is to tube up your equalizing line to a place where it that is not subject to volume changes when the burner kicks on.
For further questions about the Weight-Operated Dump Valve or any other Kimray product, contact your local Kimray store or authorized distributor.