Title of Invention

A PLASTIC SUCTION MUFFLER FOR A HERMETICALLY SEALED COMPRESSOR

Abstract

A plastic suction muffler for a hermetically sealed compressor, which comprises a muffling chamber and a perforated tube having diameter in the range of 0.1" to 1", of synthetic polymeric material passing through the muffling chamber carrying suction gas partially or fully from suction tube of the compressor to suction port on valve plate, the number of perforations varying from 4 to 120 and the diameter of the perforations ranging from 0.01 to 0.025", said perforated tube and muffling chamber being integrally moulded as two separate halves joined together.

Full Text

FORM-2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SECTION-10, rule 13 A PLASTIC SUCTION MUFFLER FOR A HERMETICALLY SEALED COMPRESSOR KIRLOSKAR COPELAND LIMITED of 1202/1 Ghole Road, Pune 411 005, Maharashtra, India, 336/mum/2000 11-04-2000 an Indian Company THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THIS INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED:- This invention relates to a plastic suction muffler for a hermetically sealed compressor. In particular, this invention relates to an improved plastic suction Muffler configuration for minimizing suction gas super heating in hermetically sealed compressors. Hermetic sealed compressors are used to compress low-pressure vapour from an evaporator and deliver high pressure and high temperature vapour to a condenser. A typical hermetic compressor working is explained in the block diagram as seen Figure 1 of the accompanying drawings. In a hermetic compressor suction gas enters the shell cavity through a suction tube [A]. This gas is sucked in the suction muffler [B] due to suction stroke of the piston. The gas flows to the cylinder bore via the suction plenum[C] in the cylinder head through a passage in the crankcase or connecting tubes between the suction muffler and suction port in the valve plate [D]. This low-pressure gas is compressed to high pressure and delivered to the discharge muffler [G] via the discharge port [E] in the valve plate to the cylinder head plenum [F]. In the discharge plenum gas is attenuated [G] and delivered to the condenser of the appliance through a discharge tube [H] connected to the discharge muffler by a discharge shock loop. The hermetic compressor generally comprises a lower and upper shell, inside which three or more resilient members hold the pump assembly (coil springs). The whole assembly body is supported by legs, which are 2 attached to a shell. The pump assembly consists of a motor component stator and rotor and gas compressor mechanism. The rotor is fitted directly on the crankshaft. The crankshaft is housed in the main bearing provided in the crankcase. The stator is mounted on the crankcase through fasteners. The power required for rotation of the crankshaft is given by a motor. In the hermetically sealed refrigeration compressor, gas enters through the suction tube and travels into the shell, which surrounds the pump assembly. The gas is further picked up by the suction pick up tube and led into the crankcase, which then goes into the suction plenum in the cylinder head through suction mufflers, which are in built in the crank case. Inside, the motor and pump assembly is cooled by refrigerant available inside the shell cavity. In this process the refrigerant picks-up heat from these (motor and pump assembly) hotter components before it reaches in to the crankcase by heat convection. It is well known from basics of thermodynamics that suction gas super heating will result in reduced compressor performance as density of gas reduces with increased temperature which means less mass flow rate in to the cylinder bore. The reciprocating mechanism used to compress the refrigerant generates a lot of pulses which if allowed to act directly on the gas cavity leads to vibration of the compressor and/or generates noise. Usually a pv)se attenuator /muffler becomes necessary on both suction and discharge 3 side of the pumping mechanism to take care of this effect. Generally the mufflers are built in the crankcase, which is of a highly conductive material, or are fitted as separate metallic components, which are good thermal conductors. The suction gas passes through these conventional gas passages either separate or in built in the crankcase and in so doing picks up heat from the surrounding hotter bodies before it reaches the bore. This is undesirable. There is also a pressure drop of about 1 psi as the suction gas passes through the muffler. This pressure drop results in decrease in the velocity of the gas and its consequent expansion. It is an object of the present invention to provide a new plastic suction muffler which reduces the effect of superheating of the suction gas to a great extent. Another object of the suction muffler is that it is designed such that it results in less pressure drops across it and good attenuation of the suction pulse for a wide band of frequencies typically from 0.5KHz to 3KHz. According to this invention there is provided a plastic suction muffler for a hermetically sealed compressor, which comprises a muffling chamber and a perforated tube having diameter in the range of 0.1" to 1", of synthetic polymeric material passing through the muffling chamber carrying suction gas partially or fully from suction tube of the compressor to suction port on valve plate, the number of perforations varying from 4 to 120 and the diameter of the perforations ranging from 0.01 to 0.025", said perforated tube and muffling chamber being integrally moulded as two separate halves joined together. 4 Typically a drain hole is provided at the bottom of the muffler chamber to drain the lubricating oil present along with suction gas. Typically the perforated tube and the muffling chamber are integrally moulded as two separate halves joined together by bonding or ultrasonic welding. The invention will now be described with reference to the accompanying drawings, in which Figure 1 is a block diagram showing the operation of the hermetically sealed compressors in accordance with this invention; Figure 2 is a schematic sectional view of the muffler in accordance with this invention; and Figure 3 is a graph showing the attenuation features of the muffler of figure 2 in use. Figure 1 of the accompanying drawings has been described in detail hereinabove. Referring to Figure 2 of the drawings, the suction muffler consists of perforated tube (1), whose diameter, shape & number of perforations 5 are designed to attenuate frequencies from 500 to 3000 Hz (fig 3), covered with muffling chamber (2) of suitable shape & size. The suction gas is picked up partially from the shell & remaining directly from suction tube of compressor is sucked through inlet (3) of the tube (1) of the suction muffler. This tube is extended up to suction port and gas is delivered to suction port of valve plate from outlet (4). Perforated holes (5)(of suitable shape, size and numbers to attenuate frequency band 0.5 to 3KHz) open in the muffling chamber (2). An oil drain hole (7), of any diameter up to 0.125" is provided at the bottom of the suction muffler to drain oil accumulated in the muffler and return it to the oil sump [not shown]. This extraction of oil also results in improving the efficiency of the compressor. The perforated tube and the muffling chamber are integrally moulded as two separate halves joined together by bonding or ultrasonic welding. Polypropylene is a preferred material for the muffler in accordance with its invention. Figure 3 shows the attenuation of noise analysis using sysnoise package. The graph shows that there is good attenuation of noise in the 0.5KHz to 3KHz frequency band, which is the audible range, and therefore results in a compressor with silent operation. ADVANTAGES: 1 .The new suction muffler configuration will avoid the suction gas super heating to great extent as well as pressure drop in the muffler. This 6 more amount of gas will be supplied for the same duration of suction valve opening resulting more mass flow rate. 2.The pressure loss is minimum in the muffler configuration in accordance with its invention as compared to other muffler configuration 3.Attenuation is good frequency band of 0.5 to 3KHz (fig.3) which is analyzed using SYSNOISE package. 7 We Claim: [1] A plastic suction muffler for a hermetically sealed compressor, which comprises a muffling chamber and a perforated tube having diameter in the range of 0.1" to 1", of synthetic polymeric material passing through the muffling chamber carrying suction gas partially or fully from suction tube of the compressor to suction port on valve plate, the number of perforations varying from 4 to 120 and the diameter of the perforations ranging from 0.01 to 0.025", said perforated tube and muffling chamber being integrally moulded as two separate halves joined together. [2] A plastic suction muffler as claimed in Claim 1, a drain hole is provided at the bottom of the muffler chamber to drain the lubricating oil present along the suction gas. [3] A plastic suction muffler as claimed in claim 1, in which the two halves are joined together by bonding or ultrasonic welding. Dated this 11th April 2000 MOHAN DEWAN Of R. K. Dewan & Co Applicants' Patent Attorney 8

Documents:

336-mum-2000-cancelled pages(14-8-2003).pdf

336-mum-2000-claims(granted)-(14-8-2003).doc

336-mum-2000-claims(granted)-(14-8-2003).pdf

336-mum-2000-correspondence(ipo)-(22-1-2007).pdf

336-mum-2000-correspondence-1-(22-11-2003).pdf

336-mum-2000-correspondence-2-(22-10-2005).pdf

336-mum-2000-drawing(11-4-2000).pdf

336-mum-2000-form 1(11-4-2000).pdf

336-mum-2000-form 13(22-1-2007).pdf

336-mum-2000-form 19(22-112003).pdf

336-mum-2000-form 2(granted)-(14-8-2003).doc

336-mum-2000-form 2(granted)-(14-8-2003).pdf

336-mum-2000-form 26(5-12-2006).pdf

336-mum-2000-form 3(26-7-2001).pdf

336-mum-2000-petition under rule 138(14-8-2003).pdf

336-mum-2000-power of attorney(11-4-2000).pdf

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