Robert L. Fischer, P.E., is a physicist and electrical engineer who spent 25 years in chemical vegetation and refineries. Fischer can additionally be a part-time college professor. He is the principal reliability advisor for Fischer Technical Services. He may be reached at bobfischer@fischertechnical.com.
One of Dirty Harry’s famous quotes was: “A man’s obtained to know his limitations.” This story illustrates why you want to know your control valve’s limitations.
A shopper recently known as for assist downsizing burners on a thermal oxidizer. Changes in the manufacturing process had resulted in too much heat from the existing burners. All attempts to decrease temperatures had ended in unstable flames, flameouts and shutdowns. The higher temperatures didn’t harm the product however the burners had been guzzling one hundred ten gallons of propane every hour. Given the high cost of propane at that plant, there have been, literally, tens of millions of incentives to preserve energy and scale 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 could be discovered on-line at https://online.flippingbook.com/view/852569. Fives North American Combustion, Inc. 4455 East 71st Street, Cleveland, OH 44015. Image courtesy of Fives North American Combustion, Inc.
เกจวัดแรงดันแก๊สหุงต้ม to retrofit smaller burners was being written. One of the plant’s engineers known as for a value estimate to change burner controls. As we discussed their efforts to cut back gas usage, we realized smaller burners won’t be required to unravel the issue.
pressure gauge 4 นิ้ว ราคา is principally decided by the place of a “combustion air” control valve. Figure 1 reveals how opening that valve will increase stress in the combustion air piping. Higher stress forces more air via the burners. An “impulse line” transmits the air strain to one aspect of a diaphragm within the “gas control valve” actuator. As air stress on the diaphragm increases, the diaphragm strikes to open the valve.
The fuel valve is mechanically “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 stable flame.
The plant was unable to take care of flame stability at considerably decrease fuel flows as a result of there’s a restricted range over which any given diaphragm spring actuator can provide accurate management of valve place. This usable management range is identified as the “turndown ratio” of the valve.
In this case, the plant operators now not needed to completely open the fuel valve. They needed finer resolution of valve position with much decrease combustion air flows. The diaphragm actuator wanted to have the ability to crack open and then management the valve using significantly lower pressures being delivered by the impulse line. Fortunately, changing the spring was all that was required to permit recalibration of the gasoline valve actuator — utilizing the existing burners.
Dirty Harry would positively approve of this cost-effective change to the valve’s low-flow “limitations.” No capital challenge. No burner replacements. No vital downtime. Only a couple of cheap elements and minor rewiring were required to avoid wasting “a fistful of dollars.”
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