Waukesha Seat Valve Holding Pressure- Everything you need to know

Have I ever started off one of these blogs not talking about how much we get a kick out of helping our customer’s solve their process challenges? I don’t think so. Today’s a new day, but the theme is the same. Recently, a customer came to us with an issue on their Waukesha W61 T body on/off valve. Their line pressure was running at 80 PSI causing the valve seat to lift and product to leak past. They needed an immediate fix, so they turned to Triplex. How did we help them? Read on to find out.

After getting some basic information about the valve (model and serial number mostly), the first thing we did was consult our trusty copy of Waukesha publication #DS-1201. DS-1201 is the factory document that not only provides a product overview and options, but also includes all the different valve orientations, dimensions, pressure loss data, and actuator holding pressures. This is an actuator holding issue, so we jumped ahead to that part of the document.

The valve in question was a 2” W61 T body valve with 4” air to raise actuator. First, we needed to find the holding pressure of their current valve. We did this by looking at the below table:

We can see that the valve leakage should be expected. P1 on a 2” W61 valve with 4” air to raise actuator will only hold closed against 70 PSI of line pressure.

So what should we do? Well, we have a couple of options. The first thing we could so is consider going to a larger actuator- perhaps a 5” or 6” air to raise actuator. But this valve was in service and the customer wanted to minimize downtime and actuator lead times were 1-2 weeks. What else could we do?

One other option to increase holding pressure on W60 series valves is to use the optional air boost (ports A & B) in the drawing above. We’ll talk more about how to calculate pressure required for air boost in a future post, but for this post just know that you can apply 5.5 PSI to the port A and get another 20 PSI of holding pressure. The drawback here is that you’ll need a precision air regulator to properly supply and vent pressure when the actuator strokes. Again, the customer is down, and we wanted to make this as simple as possible.

So what did we do? The answer was pretty simple. We recommended they go to a 4HAR spring, which has a holding pressure of 99 PSI for a 2” T body valve. The Waukesha W60 series of valve features fully maintainable actuators and contained springs, so swapping the springs out was a piece of cake. And the best part? We had the spring in stock, so they were able to get up and going the very same day!

So the next time you have a leaking seat valve, see if your valve is rated to handle the closing pressure. If it’s not, don’t worry, you have options. Consider going to a heavy-duty spring or upsizing the actuator. In higher pressure applications, consider the air boost. And as always, if you have any questions about sizing your Waukesha W60 series seat valve, contact a Triplex Sales Engineer today!

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