ไดอะแฟรม LOGO.png

Robert L. Fischer, P.E., is a physicist and electrical engineer who spent 25 years in chemical plants and refineries. Fischer can additionally be a part-time college professor. He is the principal reliability marketing consultant for Fischer Technical Services. He could additionally 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 have to know your management valve’s limitations.
A client just lately called for help downsizing burners on a thermal oxidizer. เกจแรงดันสูง within the manufacturing process had resulted in too much heat from the present burners. All attempts to lower temperatures had led to unstable flames, flameouts and shutdowns. The higher temperatures didn’t hurt the product however the burners had been guzzling 110 gallons of propane each hour. Given the excessive price of propane at that plant, there have been, actually, millions of incentives to conserve energy and scale back costs.
Figure 1. Operation of a cross related air/gas ratio regulator supplying a nozzle combine burner system. The North American Combustion Practical Pointers e-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.
A capital project to retrofit smaller burners was being written. One of the plant’s engineers known as for a price estimate to alter burner controls. As we mentioned their efforts to cut back gasoline usage, we realized smaller burners won’t be required to unravel the problem.
Oxidizer temperature is mainly determined by the place of a “combustion air” control valve. Figure 1 shows how opening that valve will increase strain in the combustion air piping. Higher stress forces more air via the burners. An “impulse line” transmits the air strain to 1 facet of a diaphragm within the “gas control valve” actuator. As air strain on the diaphragm increases, the diaphragm moves to open the valve.
The fuel valve is routinely “slaved” to the combustion air being provided to the burner. Diaphragm spring tension 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 lower gasoline flows as a result of there is a restricted vary over which any given diaphragm spring actuator can provide accurate management of valve position. This usable management range is called the “turndown ratio” of the valve.
In this case, the plant operators now not needed to completely open the fuel valve. They wanted finer decision of valve place with much decrease combustion air flows. The diaphragm actuator wanted to be able to crack open and then management the valve using significantly decrease pressures being delivered by the impulse line. Fortunately, altering the spring was all that was required to allow recalibration of the gasoline valve actuator — using the present burners.
Dirty Harry would definitely approve of this cost-effective change to the valve’s low-flow “limitations.” เกจวัดแรงดันnuovafima . No burner replacements. No vital downtime. Only a quantity of cheap components and minor rewiring have been required to avoid wasting “a fistful of dollars.”
Share