Isolation device and fluid connection

Details Isolation device and fluid connection Isolation device and fluid connection

1999-09-10

2001-04-03

Nicholson, Eric K. (Department: 3629)

Pipe joints or couplings

With casing, lining or protector

Insulated

C285S229000, C285S298000, C285S225000, C092S096000

Reexamination Certificate

active

06209927

ABSTRACT:

BACKGROUND OF THE INVENTION
Rigid connections between members in a mechanical system can be a path of vibrational propagation between members. One arrangement in which this can occur is in a refrigeration system chiller where a compressor is mounted on a heat exchanger by a rigid connection through which fluid is transferred.
Screw compressors, especially high speed geared compressors, generate high levels of structure borne energy in a frequency range where components of the systems in which they are typically applied are very responsive. This often leads to unacceptably high radiated sound levels from both the compressors and the rigidly attached system components. The problem is particularly acute with compressors designed to be directly mounted on a heat exchanger shell such that the compressor is fully supported by a flange extending directly from the shell. This is because this joint tends to transmit energy very efficiently from the compressor to the heat exchanger shell. Reducing this transmission by conventional means such as elastomeric or helical springs is very difficult due to the conflicting requirements placed on the joint. Specifically, the joint must hermetically contain the refrigerant, withstand the operating pressure in the system, and be structurally robust, especially if the joint represents the sole support for the compressor. Additionally, space requirements are often very restrictive since minimizing package size is critical.
Several designs have been formulated to address the radiation of structurebome noise. They involve structurally decoupling the compressor from the heat exchanger. When transient events occur, however, the flexibility of the isolator may allow too much compressor motion. Additionally, during pressure testing in the factory, stress levels in the isolator may induce yielding, which would have a potential negative impact on performance and reliability.
SUMMARY OF THE INVENTION
The present invention is essentially a stand alone insertion installed between a compressor and a heat exchanger which supports the compressor and provides a fluid path between the compressor and heat exchanger. A flexible metal diaphragm acts as a spring to isolate vibration while defining a portion of the fluid path thereby fully containing the refrigerant. Hence, it can be incorporated without requiring any major design changes. The metal diaphragm is of an appropriate thickness and geometry to have the needed spring constant. Because the diaphragm member is thin and horizontal, space demands in the critical vertical direction are minimized. Since the design is 100% metallic, except for the seal structure, the diaphragm can be machined to the proper configuration or, if assembled, welding can be used to guarantee hermeticity. Additionally, no material compatibility problems with refrigerant and oil are raised, as would be the case with elastomeric materials.
The present invention includes a restraint that prevents the motion of the vibration isolator during large amplitude transient events or while the chiller undergoes a pressure test in the factory. Under normal compressor operation, the restraint is not in contact with the compressor side of the isolation system/diaphragm in order to prevent acoustic short circuiting of the isolator. When the system is pressure tested, however, the diaphragm deflects until the restraint is reached, much like a valve's opening movement being limited by a valve stop. At this point, further motion of the diaphragm is limited and the restraint becomes the primary load bearing member of the assembly. During a transient event, the isolator also can deflect until the diaphragm contacts the restraint and the load is again borne by the restraint.
It is an object of this invention to reduce heat exchanger vibration due to compressor excitation in a refrigeration or air conditioning system.
It is an additional object of this invention to use a metal diaphragm as a spring and to limit movement of the diaphragm during transient motion.
It is another object of this invention to reduce structure borne sound resulting from compressor operation.
It is an additional object of this invention to reduce overall sound radiation from a chiller.
It is a further object of this invention to provide an axially compact vibration isolator. These objects, and others as will become apparent hereinafter, are accomplished by the present invention.
Basically, a metal diaphragm is provided which acts as a spring while defining a flow path. A restraint limits upward movement of the diaphragm during transient motion. Downward movement is resisted by a Belleville spring.


REFERENCES:
patent: 2038855 (1936-04-01), Rosenblad
patent: 2113047 (1938-04-01), French
patent: 2632658 (1953-03-01), Mertz
patent: 3249378 (1966-05-01), See et al.
patent: 4570440 (1986-02-01), Doran
patent: 4718702 (1988-01-01), Rushforth et al.
patent: 4804211 (1989-02-01), Larson et al.
patent: 82719 (1895-10-01), None
patent: 10199 (1912-04-01), None
patent: 739267 (1955-10-01), None

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