Application Note: Paper Machine Steam Sparging to Heat Water


Steam sparging control valve applications are common in the paper machine area of Pulp & Paper mills. Live steam is dumped into it into a tank or vat of water to heat the water. They typically will have a “sparging” nozzle on the end of the line in the bottom of the tank - basically a pipe with a series of small holes drilled into it to inject the steam into the water in small amounts to reduce vibration and shaking. However, despite the sparger it is still violent interaction as the steam condenses into water. The process generates violent shaking of the piping, and so vibration becomes the main issue needing to be addressed.

The original valve in the picture was a Fisher ED with 667 actuator and 3582 positioner (pneumatic) with a Fisher model 546 IP on the wall to convert the 4-20 ma input signal to a pneumatic 3-15psi signal to the 3582.

The shaking was causing the positioner to be damaged in a short time, and was causing repeated failures of the control valve, which in turn required constant maintenance.

Trimteck’s Solution

The Trimteck representative replaced the Fisher valve with a Trimteck OpGL Globe Control Valve, which is better suited to this application for several reasons:

  1. The OpTK Piston Cylinder Actuator is much smaller and more compact than the Fisher 667 Diaphragm Actuator. The height and width of the actuator being closer to the center of the body of the valve means that as the valve and pipe shakes and moves, there is less cantilevered force applied to the system. The accessories on the Trimteck valve therefore shake less both in terms of amplitude and acceleration.
  2. With the valve oriented on its side, the weight of the effect of side load on the guide bearings and bushings becomes an important factor in the longevity of the valve. The moving parts inside Trimteck’s OpTK Piston Cylinder Actuator weigh significantly less than those in Fisher’s larger spring-diaphragm, which means the guide bearings and bushings in the Trimteck actuator will last longer and hold up better.
  3. The Trimteck representative removed the positioner from the control valve and mounted it remotely to the wall, so that the potentiometer is the only part of the positioner mounted on the control valve. This eliminates the effect of vibration on the positioner, and the potentiometer assembly left on the valve is designed to withstand severe vibration, so the positioner assembly will now last a far longer in service.
  4. As you can see in the photo, these are fairly tight spaces for a control valve installation. With the overall size of the Trimteck OpGL Globe Control Valve being much smaller than the Fisher, it was much easier to install.

So, wherever you find sparging water heater applications, you will likely find a problem you can solve with a Trimteck valve. 

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