Compressor Valves

Avoiding Incorrect Assembly Plants should be designed so that incorrec t assembly is difficult or impossible. For example, compressor valves should be designed so that inlet and exit valves cannot be interchanged. 

If refrigerant temperature Is high and 3. Compressor valve failure. 

Davis, H., Effects of Reciprocating Compressor Valve Design on Performance and Reliability, Presented at Mechanical Engineers, London, England, October 13, 1970 (Reprint, Worthington Corp., Buffalo, NY). 

White, K. H., Prediction and Measurement of Compressor Valve Loss, ASME 72-PET-4, New York, NY American Society of Mechanical Engi neers, 1972. 

Several steps can be taken to maximize the run time for the reciprocating compressor. Since wear is a function of rubbing speed, the piston speed can be kept to a minimum. Chapter 3 made recommendations for piston speed. Reliability problems due to valves are reputed to account tor 40% of the maintenance cost of the compressor. Valves are the single largest cause for unplanned shutdowns. Basically, valve life can he increased by keeping the speed of the compressor as low as practical. At 360 rpm, the valves are operated six times a second. At 1,200 rpm, ihc valves operate 20 times a second or 1,728,000 times in a day. It is not difficult to understand why the valves are considered critical. To keep the reliability in mind, valve type, material selection and application considerations such as volume ratio, gas corrosiveness, and gas cleanliness need attention by the experts. One final note is that while lubrication is an asset to the rubbing parts, it is not necessarily good for valve reliability. 

The best compressor valves for any service selected from the unmatched Dresser-Rand line, including famous gas-cushioned Channel Valves. 

In reciprocating compressors the compressor valves themselves act as k valves, preventing backflow from high-pressure stages to lower... 

End view showing male and female rotors and slide valve on an 85-ton intermediate compressor. The robust design of the Series R compressor can ingest amounts of liquid refrigerant that would severely damage reciprocating compressor valves, piston rods, and cylinders. (Used by permission Cat. RLC-DS-2, Aug. 1995. The Trane Company.)... 

Figure 12-6G. AJAX APV-1000, high-efficiency compressor valve. Suction and discharge losses are 4-8% compared to conventional valves with losses of 6-20% as a percentage of the total indicated horsepower. (Used by permission Bui. 2-214. Cooper-...

Figure 13-5. Compressor valve diagnostics and optimization procedure (A) compressor discharge valve flutter and (B) properly operating discharge valve. (Used by permission Southern Gas Association s Gas Machinery Research Council.)...

Compressor valves are placed in each cylinder to permit one-way flow of gas, either into or out of the cylinder. There must be one or more valve(s) for inlet and discharge in each compression chamber. 

Using this easy technique, we can guide the maintenance effort as to which reciprocating compressor valves must be overhauled, and which valves are working correctly. 

The MTBFs for all equipments are obtained from Center for Chemical Process Safety (1989) and the maintenance time is obtained from Bloch and Geitner (2006) (for pumps, compressors, valves) or estimated if the information is not available (for other equipments). Our example shows the results when the PM time intervals are optimized. Other variables are fixed ten employees, keeping inventory for all spare parts and reasonable numbers for the PM starting time. The maintenance model and the GA are implemented in Fortran running on a 2.8 GHz CPU, 1028 MB RAM PC. The final results for the fraction a (PM time interval = o MTBF) are shown in table 3. 

Temperature chiller. If refrigerant temperature is high and approach temperature on chiller is normal, check 1. Chiller pressure. bypass. 3. Compressor valve failure. 4. Compressor suction pressure restriction. 5. Low compressor speed. 

Major polymer applications metal compressors in aerospace applications, pump housings, compressor valve plates, bushings, bearings, wear pads, piston rings and seals, gears, fasteners, plastic engine... 

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