Patent Grant
9863421
This application claims the benefit and priority of Indian Patent Application No. 1411/MUM/2014, filed Apr. 19, 2014. The entire disclosure of the above application is incorporated herein by reference.
The present disclosure relates to a compressor, and more particularly to reducing pressure pulsations in a compressor.
This section provides background information related to the present disclosure and is not necessarily prior art.
A compressor is one of the most important pieces of equipment used in an HVAC (Heating, Ventilation and Air-Conditioning) system. Compressors are used to control the circulation of refrigerant within the HVAC system, by drawing in refrigerant at low pressure and low temperature and delivering it at a higher pressure and temperature to the system. Depending on the capacity requirements of HVAC applications, different compressors are used such as reciprocating and rotary, including scroll compressors, screw compressors, and the like.
Reciprocating compressors typically have one or more pistons that are used to compress refrigerant to increase its pressure. Reciprocating compressors use the reciprocating action of a piston inside a cylinder to compress refrigerant. The piston is driven up/down or back/forth by a crankshaft. The cylinder includes an inlet and an outlet for entry of refrigerant and exit of compressed refrigerant respectively. Refrigerant entering the cylinder through the inlet is compressed by an upward movement of the piston in the cylinder. As the piston is driven upward in the cylinder, refrigerant in the cylinder is compressed prior to exiting out of the cylinder through the outlet when the required compression pressure has been achieved.
Scroll compressors include two disks, each including a spiral wrap. The spiral wraps of the two disks are nested together, wherein a first disk is stationary and a second disk is moving around the first in an orbital fashion. Refrigerant is sucked in through an inlet typically located at the perimeter of the nested disk arrangement and gets trapped in a space between the two nested disks. As the second disk moves in relation to the first disk, refrigerant in the space between the disks is compressed and reaches a high pressure and temperature. Compressed refrigerant is then discharged through an outlet typically located at the center of the first disk.
Compressed refrigerant then enters a piping system for being transported to other equipment connected to the compressor of the HVAC system where it is needed. The aforementioned methods of operation cause compressed refrigerant to be delivered to the piping system or other equipment in pulses instead of a continuous flow. As a result, compressed refrigerant, when being discharged into a small volume such as a short pipe, can cause pressure fluctuations in the associated piping system. Several undesirable effects of pressure fluctuations appear in the piping system and/or the equipment connected to the compressor or within the compressor itself. All of these undesirable effects are due to discharge pulsations which appear as a result of the pulsating action of the compressing means such nested disks, a piston, or the like. A major drawback which arises from discharge pulsations is the effect of vibration such as rattling which appears in the piping system and/or other equipment connected to the compressor, and can potentially damage the piping system and/or the equipment connected to the compressor. When the discharge pulsations are severe, the vibration/rattling is frequently accompanied by considerable noise, which radiates from the piping system. Severe discharge pulsations can also considerably decrease the efficiency of the compressor.
In order to absorb or dampen the pressure fluctuations, an oversized piping system is typically used. However, an oversized piping system results in heavier pipes, which can lead to maintenance issues and cost escalation. Another alternative is to provide a discharge cavity at the outlet of the compressing means whereby the volume of the cavity facilitates a reduction in the discharge pulsations. However, in order to provide a discharge cavity, the size of the shell/housing of the compressor needs to be increased, thereby making the compressor heavy, large, and difficult to service. Additionally, a discharge muffler is typically coupled to the outlet of the compressor to attenuate discharge pulsations generated by the compressor. However, acoustic characteristics of the discharge muffler are extremely important in achieving efficient pulsation dampening. Furthermore, existing discharge mufflers may share a large partition with the suction/inlet portion of the compressor. The high temperature of the discharge muffler can transfer heat to the inlet portion of the compressor and decrease the efficiency of the compressor.
Hence, there is a need for a mechanism that can effectively dampen discharge pulsations while occupying less space and increasing the efficiency of the compressor.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
In accordance with one aspect of the present disclosure, a pulsation dampening assembly for compressors is provided. The pulsation dampening assembly is adapted to be disposed in an outlet port configured in a housing of a compressor for supplying compressed refrigerant outside the compressor. The pulsation dampening assembly includes an insert, a first helical spring, a second helical spring, and a pulsating disc. The insert may be adapted to be attached to the outlet port. The insert may include a base, a wall extending from the base, and a through-hole defined by a first diameter portion and a second diameter portion of the wall. The first diameter portion may include a plurality of first apertures located adjacent to said second diameter portion. The base may abut the housing of the compressor when the insert is attached within the outlet port. The first helical spring and the second helical spring may be co-axially spaced apart within the through-hole of the insert. The pulsating disc positioned between the first and second helical springs in the through-hole. The disc may include a cylindrically shaped lower portion, a flange, and a spring supporter. The cylindrically shaped lower portion may include an open bottom end for facilitating entry of compressed refrigerant in the lower portion, and a plurality of second apertures in a wall of the lower portion. Each second aperture and each first aperture may facilitate exit of compressed refrigerant from the lower portion. The flange may be integral with the cylindrically shaped lower portion and located on a top end of the cylindrically shaped lower portion. A bottom surface of the flange may seal the top end. The flange may include a plurality of recesses equidistantly located along a periphery of the flange. A location of each recess may correspond to a location of each second aperture for facilitating passage of compressed refrigerant exiting the second apertures. The spring supporter may be integral to the flange and located on a top surface of the flange. The spring supporter may be adapted to facilitate the first helical spring to rest on the top surface. The pulsation dampening assembly may be adapted to be displaceably configured between an operative state and an inoperative state. In the operative state, the first apertures and the second apertures may be aligned to facilitate exit of compressed refrigerant. In the inoperative state, the first apertures and the second apertures may not be aligned.
In some configurations, an inner side of the wall of the insert may form the second diameter portion and may include an upper shoulder, a retainer, and at least one vertical groove. The retainer may be integral with the inner side of the wall. The at least one vertical groove may extend from the upper shoulder to the retainer.
In some configurations, an outer side of the wall of the insert may form the second diameter portion and may include a ring located at a lower portion of the outer side of the wall. The ring may be integral with the outer side and the base. The ring and the base may be adapted to lock the insert in the outlet port.
In some configurations, the second helical spring may rest on the retainer of the second diameter portion.
In some configurations, an outer side of the wall of the cylindrically shaped lower portion may include at least one aligning element extending from the top end to the bottom end of the lower portion. The aligning element may be complementary to the vertical groove.
In some configurations, the outer side of the wall of the cylindrically shaped lower portion may engage with the inner side of the wall of the insert forming the second diameter portion.
In some configurations, the bottom end of the cylindrically shaped lower portion may rest on the second helical spring.
In some configurations, the recesses may be arcuate shaped recesses.
In some configurations, the supporter may be ring shaped and the outside of the wall of the supporter may engage with the inside of the first helical spring.
In some configurations, in the operative state, the first apertures and the second apertures may be co-axial.
In some configurations, in the inoperative state, the flange may rest on the upper shoulder of the second diameter portion.
In accordance with another aspect of the present disclosure, a pulsation dampening assembly for a compressor is provided. The compressor may include an outlet port configured for supplying compressed refrigerant from a compression mechanism of the compressor. The pulsation dampening assembly may include a pulsating disc and a spring. The pulsating disc and the spring may be disposed within the outlet port. The pulsating disc may include a plurality of apertures in fluid communication with the compression mechanism. The spring may include a first end engaging the pulsating disc and a second end engaging the outlet port. The pulsating disc may be translatably disposed within the outlet port between an operative state and an inoperative state.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Discharge pressure pulsation comes from discontinued nature of refrigerant flow in compressors due to pulsating action of compressing means such as scroll disks, pistons, and the like. Several undesirable effects of discharge pulsations appear in the piping system and/or the equipment connected to the compressor or in the compressor itself. In order to absorb or dampen out discharge pulsations, a discharge cavity is typically provided at the outlet of the compressing means whereby the volume of the cavity facilitates reduction in discharge pulsations. Referring to
The efficiency of the compressor 100 can be improved by preventing heat transfer (HT) from the discharge cavity 101 to the suction cavity 102 through the muffler plate 103. However this would require a large discharge cavity, whereby heat transfer can be avoided and discharge pulsations can also be reduced. A large discharge cavity will make the compressor bulky and difficult to service. Reducing the volume of the discharge cavity will be ineffective as it will increase discharge pulsations of the compressor.
Alternatively, heat transfer can be reduced by replacing the discharge cavity by a direct discharge line. Referring to
Additionally, heat transfer and discharge pulsations can be reduced by replacing the discharge cavity by an external discharge muffler. U.S. Pub. No. 2009/0116977 discloses a scroll compressor coupled to an external discharge muffler having a valve therein for facilitating the flow of refrigerant. However, the shape and size of the muffler and the placement of the valve within the muffler leads to several geometrical constraints in coupling the muffler to the compressor and makes the muffler cumbersome to use.
Referring to
Furthermore, scroll compressors are susceptible to reverse rotation typically during shutdown. Reverse rotation occurs when compressed refrigerant discharged through the outlet 104 of the compression mechanism of the scroll compressor 100 moves back through the outlet 104 into the compression mechanism, causing the spiral wound disks 105 of the scroll compressor 100 to move in reverse orbital direction in relation to each other. This is undesirable as it results in unwanted noise from the compressor and can also harm the internal components of the compressor. Reverse rotation can be avoided by deploying a shutdown device for closing the outlet 104 of the compressing means. The shutdown device is typically a discharge valve disposed within the outlet 104 of the compression mechanism. The discharge valve closes during shutdown of the compressor, thereby closing the outlet 104 of the compression mechanism. However, any malfunctioning of the shutdown device can needlessly close the outlet 104, thereby hindering the operation of the compressor and rendering the shutdown device ineffective and also leading to maintenance issues.
Thus to overcome these aforementioned limitations, the present disclosure envisages a pulsation dampening assembly to effectively dampen discharge pulsations of a compressor and at the same time increase the efficiency of the compressor and also prevent reverse rotation.
The pulsation dampening assembly of the present disclosure will now be described with reference to the embodiments shown in the accompanying drawings. The embodiments do not limit the scope and ambit of the disclosure. The description relates purely to the examples and preferred embodiments of the disclosed pulsation dampening assembly and its suggested applications.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
Referring to
Referring to
Referring to
The pulsation dampening assembly is configured to be displaceable between an operative state wherein the first apertures 354 and the second apertures 303 are aligned to facilitate exit of compressed refrigerant, and an inoperative state wherein the first apertures 354 and the second apertures 303 are not aligned and the flange 305 rests on the upper shoulder 357. Typically, the first apertures 354 and the second apertures 303 are generally coaxial in the operative state and non-coaxial in the inoperative state. In the operative state, compressed refrigerant discharged from the outlet 377 of compressing means hits the pulsating disc 300 and pushes it against the spring force. The pulsating force exerted by discharged refrigerant will be opposed by the springs 325a, 325b and all the pulsation energy will be absorbed by the springs 325a, 325b thereby reducing discharge pulsations considerably.
Referring to
Referring to
Referring to
Referring to
Thus discharge pulsation dampening is achieved by the aforementioned spring operated floating discs.
The springs 402, 502 used in the aforementioned embodiments, are specially designed to ensure dampening of refrigerant discharge pulsations. The design calculations considered to achieve the required stiffness of the helical spring 502 are as described below:
K=F/δ=Gd/(8C3n)(C2/(C2+0.5))
wherein C=Spring Index D/d
d=wire diameter(m)
D=Spring diameter=(Di+Do)/2(m)
Di=Spring inside diameter(m)
Do=Spring outside diameter(m)
DN=Spring inside diameter(loaded)(m)
E=Young's Modulus(N/m2)
F=Axial Force(N)
G=Modulus of Rigidity(N/m2)
However, the term (C2/(C2+0.5)) which approximates to 1 can be ignored. Hence,
K=F/δ=Gd/(8C3 n)
The results of tests performed on the pulsation dampening assembly of the present disclosure are provided below. The results are shown as a percentage variation from a baseline compressor as depicted in
Minimum gain in EER (Energy Efficiency Ratio)=1%
Maximum gain in EER=13%
Minimum gain in Heat Capacity=0.92%
Maximum gain in Heat Capacity=12%
Minimum gain in Mass Flow=0.92%
Maximum gain in Mass Flow=12%
Furthermore, power consumption is also reduced.
Further, the results of sound and pulse tests performed on the pulsation dampening assembly of the present disclosure show that a significant drop of 72% in pressure of discharge pulse is achieved by the pulsation dampening assembly of present disclosure as compared to the direct discharge line, as illustrated in
Thus the results clearly indicate improved performance of the pulsation dampening assembly of the present dislcosure.
Dampening of discharge pulsations is also achieved by additional embodiments.
Referring to
Referring to
Referring to
Referring to
Throughout this specification the word “comprise,” or variations such as “comprises” or “comprising,” will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the invention as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the invention, unless there is a statement in the specification specific to the contrary.
When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1411/MUM/2014 | Apr 2014 | IN | national |
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| Office Action regarding Chinese Patent Application No. 201510175397.2, dated Nov. 1, 2016. Translation provided by Unitalen Attorneys at Law. |
| Number | Date | Country | |
|---|---|---|---|
| 20150300353 A1 | Oct 2015 | US |
