Screw compressor acoustic resonance reduction

Abstract

A screw compressor for acoustic resonance reduction and refrigeration systems including the screw compressor are disclosed. The screw compressor has an acoustic barrier integral with the compressor housing for use with a slide valve assembly that includes a piston connected to a slide valve. A shaft connecting the slide valve and the piston passes through an aperture in the barrier with the piston and the slide valve disposed on opposite sides of the barrier. The acoustic barrier protects the piston from discharge pulses of compressed fluid exiting the rotors of the screw compressor, thus attenuating acoustic resonance, reducing compressor noise and premature wear of the slide valve assembly and compressor housing.

Description

FIELD OF THE INVENTION [0001] The present invention is directed to a screw compressor having a slide valve used in gas compression, and more particularly to a screw compressor for use in heating, ventilation, air conditioning and refrigeration systems that reduces acoustic resonance, slide valve and compressor housing wear, and compressor noise levels. BACKGROUND OF THE INVENTION [0002] Screw compressors are widely used to compress many types of gases, particularly those used in heating, ventilation, air conditioning and refrigeration (HVAC&R) systems. The capacity of the screw compressor is typically regulated by a mechanism called a slide valve. [0003] Rotary screw compressors of the type which are utilized for compressing a refrigerant gas or other fluid conventionally include a pair of rotors having intermeshing lands and grooves helically disposed about the periphery thereof. A working fluid enters the compressor from an inlet port and enters the grooves between the rotors. The...

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Benefits of technology

[0014] An advantage of the present invention is that an integral acoustic barrier placed between the piston of the slide valve assembly and the discharge from the rotors greatly reduces the possibility of creating an acoustic resonance resulting from periodic discharge of compressed refrigerant gas from the compression chambers as the integral barrier attenuates sound and vibration.

[0015] Another advantage of the present invention is that an integral acoustic barrier placed between the piston of the slide valve assembly and the discharge from the rotors reduces wear to the slide valve assembly.

[0016] Yet another advantage of the present invention is that an integral acoustic barrier placed between the piston of the slide valve assembly and the discharge from the rotors decreases compressor noise levels.

[0017] Still another advantage of the present invention is that an acoustic barrier formed integrally with the compressor housing can be produced as part of the manufacturing process of the compressor housing, decreasing the number of additional parts in the compressor housing, reducing possible sources of leaks and potential failures, while simplifying assembly.

[0018] Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.

Problems solved by technology

These discharge pulses are of very high energy and may result in vibrations causing excessive wear to the slide valve assembly and increased noise levels in the compressor.

This in turn cause even faster wear to the slide valve assembly, including the slide valve, piston seal and mating surfaces of the slide valve assembly with the compressor housing.

The stated purpose of the '168 Patent is to reduce lubricant in the gas admitted into the valve to operate the slide valve, but it does not recognize the problem of vibration and acoustic resonance.

While the two piston system of the '894 Patent opines that the use of the seals on the rods could isolate the pistons from variations in the discharge manifold, it fails to recognize the problems caused by the reflection of energy from discharge pulses through the slide valve assembly, including acoustic resonance, noise, and excessive wear.

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