what meant by the process of unloading the Compressors?
What are the quality control records of the Compressors we have to keep.
My client looking for the answer for the above from a reciprocative compressor.
- oil field trashLv 71 decade agoFavorite Answer
Compressor unloading typically address method of controlling the capacity of a reciprocating compressor.
There are several ways to do this.
One is to reduce the suction pressure there by changing the ACFM to the compressor suction which results in less vapor for the compressor to compress.
Another is to change the clearance of the cylinder in order to affect the volumetric efficiency of the cylinder and there by change the amount of vapor being compressed.
The third way is to disable the suction valves on the cylinder so that the compressor effectively can't complete the compression cycle.
On a double action cylinder it is possible to use clearance changes or valve unloaders on either the head end or the crank end or both depending on the compressor's design.
As to the question about compressor quality control. It is not clear if you are asking about quality control during the manufacturing process, the installation process or during actual opertion.Source(s): http://www.blackmer.com/cbpdf/cb039.pdf http://www.arielcorp.com/application_manual/arield... http://www.gepower.com/businesses/ge_oilandgas/en/...
- 1 decade ago
he answered your question in regards to an air compressor. Since I am an HVAC guy, I will answer it in regards to that, since you were not clear on the application.
In regards to the compressors on Chillers, unloading refers to the reduction of the cooling capacity of the chillers due to the cooling load in a space being satisfied without having to run the chillers at maximum capacity. Chillers are sized for worst case based on ASHRAE design conditions. Since this case doesn't happen but a few times a year, the rest of the time, you only have to run your chiller at part load. To accomplish this, with a reciprocating compressor on a chiller, well, you don't. What you do is put multiple compressors that add up to the total load of the chiller. An example would be, if you had a 100 ton chiller, you put 4 25 ton compressors. What that allows you to do is completely turn off one compressor and runt at 75 tons, or 75% capacity. Reciprocating chillers have a limitation as to how much the can unload, and that is the capacity of the smallest compressor. That is why you try and get as many compressors as possible, so you can unload to a smaller capacity, especially in areas where the building cooling load varies greatly from minimum to maximum. There are limitations for this due to size and cost. To achieve better unloading capabilities, you would want to use a rotary type compressor. Screw type compressors can unload down to 10% by controlling the speed at which the compressor rotates.
Hope this helps if you were looking for this info.
- 4 years ago
Compressor cylinder unloading reduces the capacity of a reciprocating compressor by what?