Robert L. Fischer, P.E., is a physicist and electrical engineer who spent 25 years in chemical crops and refineries. Fischer is also a part-time school professor. He is the principal reliability marketing consultant for Fischer Technical Services. He could also be reached at bobfischer@fischertechnical.com.
One of Dirty Harry’s well-known quotes was: “A man’s obtained to know his limitations.” This story illustrates why you have to know your management valve’s limitations.
A consumer lately referred to as for help downsizing burners on a thermal oxidizer. Changes within the manufacturing process had resulted in an excessive quantity of warmth from the prevailing burners. All attempts to lower temperatures had resulted in unstable flames, flameouts and shutdowns. The greater temperatures didn’t hurt the product however the burners have been guzzling one hundred ten gallons of propane each hour. Given เกจ์วัดแรงดันลม of propane at that plant, there were, actually, hundreds of thousands of incentives to preserve vitality and cut back prices.
Figure 1. Operation of a cross connected air/gas ratio regulator supplying a nozzle combine burner system. The North American Combustion Practical Pointers book may be discovered online at https://online.flippingbook.com/view/852569. เกจวัดแรงดันco2 , Inc. 4455 East 71st Street, Cleveland, OH 44015. Image courtesy of Fives North American Combustion, Inc.
A capital venture to retrofit smaller burners was being written. One of the plant’s engineers referred to as for a worth estimate to change burner controls. As we mentioned their efforts to reduce fuel utilization, we realized smaller burners might not be required to solve the issue.
Oxidizer temperature is principally decided by the place of a “combustion air” management valve. Figure 1 reveals how opening that valve increases stress in the combustion air piping. Higher strain forces extra air through the burners. An “impulse line” transmits the air pressure to 1 side of a diaphragm in the “gas management valve” actuator. As air strain on the diaphragm will increase, the diaphragm moves to open the valve.
The gas valve is automatically “slaved” to the combustion air being equipped to the burner. Diaphragm spring rigidity is adjusted to ship the 10-to-1 air-to-gas ratio required for steady flame.
The plant was unable to maintain up flame stability at significantly decrease gasoline flows because there is a limited range over which any given diaphragm spring actuator can provide correct control of valve place. This usable management vary is named the “turndown ratio” of the valve.
In this case, the plant operators now not needed to totally open the fuel valve. They wanted finer decision of valve position with much lower combustion air flows. The diaphragm actuator needed to have the ability to crack open after which control the valve using considerably lower pressures being delivered by the impulse line. Fortunately, altering the spring was all that was required to allow recalibration of the gas valve actuator — utilizing the present burners.
Dirty Harry would undoubtedly approve of this cost-effective change to the valve’s low-flow “limitations.” No capital venture. No burner replacements. No significant downtime. Only a couple of inexpensive parts and minor rewiring were required to save heaps of “a fistful of dollars.”
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