KR100789335B1 - Suction and discharge valve arrangement for a small hermetic compressor - Google Patents

Abstract

One end is closed by a valve plate 10, the valve plate 10 of the type comprising a compression cylinder 1 having a suction pipe 5 adjacent thereto and disposed generally perpendicular to the axis of the cylinder. In the intake and discharge valve arrangement for a small hermetic compressor, the valve plate 10 has a discharge orifice 11 and a suction passage P which are generally centered with respect to the axial projection 20 of the inner contour of the compression cylinder 1. Has at least one suction orifice 12 which forms an extension of at least a portion of the head and is directed into the axial protrusion 20 of the inner contour of the compression cylinder 1, the suction passage P having an end thereof Is opened towards the inside of the compression cylinder 1, the opposite end of which is connected to the suction pipe 5 by a transition part T which is opened towards the suction pipe 5 and configured to minimize the load loss.

Description

Suction and discharge valve arrangement for a small hermetic compressor

The present invention relates to inlet and outlet valve devices for hermetic compressors of the type used in small refrigeration units such as refrigerators, freezers, chillers and the like.

The efficiency of the small hermetic compressor of the refrigeration system is greatly affected by the performance of the valve in the control of the gas flow.

Household refrigeration compressors use one-way valves to control the gas flow during operation. The intake valve controls the flow of gas from the intake line connected to the low pressure side of the refrigeration system, and the discharge valve controls the gas already compressed to send to the high pressure side of the refrigeration system.

Inlet and outlet valves typically include one or more orifices for gas passage, and vanes attached at one end of both ends, and when a pressure differential occurs through the valve, the vanes are displaced to direct the gas to the required direction. Pass it through.

In order to facilitate the manufacturing process, the suction and discharge orifices usually have a circular cross section and consist of a steel plate known as a valve plate. In most cases and mainly when the hermetic compressor is compact, not only the geometry of the intake valve and the intake and discharge orifices, but also the requirement to separate the already compressed gas from the gas under suction pressure (mainly fulfilled by the cylinder cover) This causes the discharge orifice to be eccentrically disposed about the center axis of the compression cylinder, so as to be very close to the wall of the cylinder (FIG. 1). Thus, the suction orifice can also be received in the axial projection of the inner contour of the compression cylinder to maintain a constant minimum distance with respect to the discharge orifice.

However, during the discharge, it is necessary to supply additional power to the gas to overcome the energy losses in the valves and the discharge muffler before flowing to the refrigeration system. This additional power may be called overpressure power, which reduces the efficiency of the compressor. In this state, the piston is located very close to the top dead center of the machine so that the compression chamber has a small height, which greatly increases the load loss of the gas that must flow through the discharge orifice and then pass through the discharge valve. The more eccentric the position of the outlet orifice, the greater the loss. An example of this phenomenon is described in Brazilian patent application PI 6,793,538, which is discussed here with regard to the irregular loading on the vanes, the effect of which affects the reliability of the vanes. However, in this conventional solution, since the compressor is not compact, the discharge orifice can be arranged in the center of the compression chamber.

In the construction of medium and large compressors, suction from the suction pipes is carried out in the cylinder cover region by means of curves and cross sections with the radius required to ensure that the entire cross section of the suction orifice can be used completely and uniformly by the gas flow coming from the suction pipe. There is enough space to provide a change of direction of the gas flowing into the orifice. The bending imparted to the gas flow passing from the suction pipe to the suction orifice (s) can be achieved such that the entire cross section of the suction orifice is suitably used as the gas flow passage.

As described above, in addition to the situation where space is available, in solutions such as described in Brazilian Patent Application No. 6,793,538, the suction chamber is opened directly to the suction orifice and provided to the cylinder head so that the suction orifice ( S eliminates the problem of abrupt changes in the direction of the gas flowing directly.

During compression, the intake valve receives a load calculated by the formula (Pcil-Ps) Ao, where Pcil is the pressure in the cylinder, Ps is the evaporation pressure, and Ao is the area of the orifice. In a known solution of the vane structure for the intake valve, the vanes are bent over the intake orifice and subjected to bending stress. When the bending stress is higher than the limit fatigue stress of the vane material, the valve breaks due to the bending fatigue. The stress on the vanes is a function of the orifice shape. The circular orifice exerts high stress on the valve at exactly the center point because the center point is at the same distance from the area (valve seat) in which the valve is seated.

Accordingly, it is an object of the present invention to minimize the pressure difference present in known prior art structures, thereby reducing power loss and load during compression without compromising the effective clearance of the gas flow through the intake orifice and the intake orifice with respect to the outlet orifice. SUMMARY OF THE INVENTION It is an object of the present invention to provide a suction and discharge valve arrangement for a small hermetic compressor that makes it possible to position the discharge orifice in the valve plate in such a way as to reduce losses.

The present and other objects are a suction and discharge valve device for a small hermetic compressor of a type including a compression cylinder, the compression cylinder having an end closed by a valve plate and supplied with gas by a suction pipe, A suction pipe is disposed adjacent the valve plate and substantially orthogonal to the axis of the compression cylinder, the valve plate comprising a discharge orifice disposed substantially centrally with respect to the axial projection of the inner contour of the compression cylinder; Having at least one suction orifice positioned outside the contour of the discharge orifice inside the axial protrusion of the inner contour of the compression cylinder to maintain a constant minimum distance from the discharge orifice, the suction orifice having one end Is open to the inside of the compression cylinder and the opposite end is an at least part of a suction passage opened to the suction pipe by a transition portion, the transition portion being provided to one of the suction passage and the portions formed by the suction pipe, the entire cross section of the suction orifice An inlet and outlet valve device for a small hermetic compressor, characterized in that it has a cross section shaped to impart a change of direction to the gas flow that allows it to be fully used in this gas flow passage.

1 schematically shows a plan view of a valve plate viewed from the compression cylinder side, showing a suction valve, a suction orifice and an discharge orifice constructed in accordance with the prior art.

Figure 2 schematically shows a longitudinal cross-sectional view of a valve plate of the valve arrangement of the invention connected to a cylinder cover and a suction muffler.

FIG. 3 schematically shows a plan view when the valve plate of the valve device of the present invention is connected to the suction muffler shown in FIG. 2.

FIG. 4 schematically shows a top view of the valve plate of FIG. 3, similar to FIG. 1 but without the intake valve.

The present invention is described in the context of a compact hermetic compressor. This compact hermetic compressor comprises a motor-compressor assembly having a cylinder block forming a compression cylinder 1 inside a shell (not shown), and in this compression cylinder 1, A reciprocating piston that sucks and compresses refrigerant gas when housed by an electric motor is housed. One end of the compression cylinder 1 is closed by a valve plate 10, which valve plate 10 is attached to the cylinder block and has a discharge orifice 11 and at least one suction orifice 12. In the compression cylinder 1, a compression chamber 2 is formed between the upper end of the piston and the valve plate 10. The cylinder block further has a cylinder lid 3 attached to the valve plate 10 so as to separate the high pressure side from the low pressure side and forming an intake chamber and an outlet chamber (not shown) therein. The suction chamber and the discharge chamber are selectively in fluid communication with the compression chamber 2 through the discharge orifice 11 and the suction orifice 12. Each is kept in communication. These optional Communication is achieved by opening and closing the suction and discharge valves, which are in the form of valve vanes acting on the suction orifice 12 and the discharge orifice 11, respectively. In addition, the valve plate 10 further supports a suction muffler 4 (FIGS. 2 and 3).

In the structure of the compact compressor as described herein, a suction pipe 5 adjacent the valve plate 10 and disposed substantially perpendicular to the cylinder axis is formed through the cylinder lid 3. In the structure shown, this suction pipe 5 is formed by a pipe that feeds gas into the suction orifice 12 through the cylinder cover.

According to this embodiment, the suction pipe is connected to the suction muffler 4.

According to the invention, the valve plate 10 has a discharge orifice 11 disposed substantially centrally with respect to the axial protrusion 20 (diameter D) of the inner contour of the compression cylinder 1 and at least one suction orifice. Has 12. This suction orifice 12 is contoured of the discharge orifice 11 inside the axial protrusion 20 of the inner contour of the compression cylinder 1 so as to maintain a constant minimum radial distance “d” from the discharge orifice 11. It is arranged outside of. The gap d is defined at least on the surface of the valve plate 10 facing inwardly of the compression cylinder 1, and can appropriately press the sealing gasket in order to avoid an unjust flow of gas from the high pressure side to the low pressure side. Is calculated to form the wall thickness.

The spacing between the orifices on each side of the valve plate 10 is determined to obtain a larger sealing area between the suction side and the discharge side. In the structure shown, the radial spacing between the discharge orifices 11 and the adjacent contours of the suction orifices 12 on the other side opposite the inwardly facing surface of the compression cylinder 1 is, for example, the minimum described above. Smaller than the radial spacing d.

According to the invention, the discharge orifice 11 is circular and coaxial with the inner contour of the compression cylinder 1. The suction orifice 12 is substantially concentric with at least one of the inner contours of the compression cylinder 1 and the discharge orifice 11, and has an annular fan shape having a small dimension d1 and a large dimension d2 (see FIG. 4). ).

In this embodiment, the suction orifice 12 integrally forms the suction passage P, which has one end open to the inside of the compression cylinder 1 and the opposite end sucks in. It opens to the pipe 5 and is connected to the suction pipe 5 by a transition portion T. This transition part T is generally in the form of a duct part whose inner contour is at least partially bent and connected to one of the parts formed by the suction passage P and the suction pipe 5. In addition, the transition portion T has a cross section suitable for causing the entire cross section of the intake orifice 12 to be fully used as a gas flow passage and configured to impart the necessary direction change to the gas flow coming from the intake pipe 5.

In the solution described here, the transition portion T is formed by the end of the suction orifice 12 towards the suction pipe 5, and at the time of passage from the suction pipe 5 to the suction passage P, In (T), it has a cross section in the shape which maximizes the bending radius of the direction change which a gas flow receives. In the structure shown, this suction passage P is formed integrally with the suction orifice 12 disposed through the valve plate 10.

According to the present invention, as described above, the cross section of the transition portion T formed by the suction orifice 12 is better because the gas follows the bending necessary to maximize the use of the cross section of the suction orifice 12. Is used.

In a variant (not shown) of the present embodiment, the shape of the transition portion T is provided with a suction pipe 5, a suction muffler, in order to provide the desired curvature for the gas flow entering the interior of the compression cylinder 1. 4), or also in the cylinder lid 3. In another structural choice, the bending of the path of the gas flow towards the inside of the compression cylinder 1 is carried out by means of the suction orifice at the inner part of the transition portion T formed by the gas introduction end 12a of the suction orifice 12. It may also be obtained by a step provided in front of 12).

According to the present embodiment, the suction orifice 12 has a gas introduction end 12a and a gas discharge end 12b, and the gas introduction end 12a is on the opposite side of the surface facing inwardly of the compression cylinder 1. Opening to the face of the valve plate 10 and forming a transition portion T directly connected to the suction pipe 5, the gas outlet end 12b being face of the valve plate 10 facing inwardly of the compression cylinder 1. Is open.

In the structure of the present invention, the suction orifice 12 provided on the valve plate 10 does not provide a cylindrical contour and does not provide a wall having a constant dimension along the thickness of the valve plate 10.

According to the illustrated embodiment, the gas introduction end 12a of the intake orifice 12 has a cross section larger than that of the gas discharge end 12b and forms the transition portion T. FIG. The gas introduction end 12a is formed in a bow shape through the thickness of the valve plate 10, concentrates at a part of its contour to form a gas receiving funnel, and the gas flow to the valve plate 10 in this region. The change in the direction of X is made less abruptly, thus minimizing the load loss caused by the sudden change in the gas flow direction from the suction pipe 5 to the interior of the suction orifice 12 of the valve plate 10.

The intake orifice 12 is formed in relation to the axial projection of the contour of the compression cylinder 1 and to optimize the gas flow through the valve plate 10 without causing high load loss, and the outlet orifice 11 Adjoining the contours of the < RTI ID = 0.0 >) < / RTI >

The suction orifice 12 of the present invention provides a higher effective gas flow area in the same geometric area of the gas passage; Make significant use of the geometric area of the suction orifice 12 even with the gas supply from the suction pipe being perpendicular and adjacent to the suction orifice 12; It has the major advantages of optimizing the relationship between the area of the intake orifice 12 and the thickness of the valve vanes to reduce power dissipation in the intake valve.

According to the invention, in the valve plate 10, a suction valve vane 30 is attached at its end portion 31 to its face facing the interior of the compression cylinder 1, and the other of the suction valve vanes 30. The end portion 32 is displaced between a closed valve position that blocks the suction orifice 12 by an elastic deformation and an open valve position that opens the suction orifice 12. The intake valve vanes 30 are located outside of the axial projection of the contour of the discharge orifice 11 inside the axial projection 20 of the inner contour of the compression cylinder 1.

According to the embodiment shown, the intake valve vanes 30 have a generally "U" shaped contour. The base of the “U” contour defines an end portion 32, the end portions 31, 32 being opposite to each other, the area of the valve plate 10 opposite to the discharge orifice 11. Located in the field The proposed solution provides the suction orifice 12 with a new geometry that makes it possible to position the discharge orifice 11 as close as possible to the central region of the compression cylinder 1.

The importance of centering the discharge orifice 11 is due to the discharge of compressed gas when the piston is very close to the top dead center of the machine. In this case, by arranging the discharge orifice 11 in the center, the pressure difference along the compression cylinder 1 is reduced during the period in which the discharge of the compressed gas through the discharge valve takes place. This reduction in pressure difference directly reduces the power lost during compression and promotes the high efficiency of the compressor.

For example, a “U” shaped suction valve vane with a small inlet radius as shown in FIGS. 3 and 4 makes it possible to change the geometry of the suction orifice 12 and to optimize this suction orifice 12. The illustrated form (along with the gas flow) produces the effect of providing a gas flow coming from the suction muffler 4 with about 90 ° of curvature before passing through the suction orifice.

As a function of the geometry of the intake orifice of the present invention, the intake valve vanes can provide a reduced thickness compared to the vanes of the prior art to maintain the same reliability and reduce loss during inhalation. This advantage is obtained because the solution of the invention makes it possible to minimize the bending stress on the intake valve vanes in the region of the intake orifice during discharge.

In the structure of the present invention, the intake valve vanes are substantially seated at the edges that form the intake orifice 12 and are radially spaced apart from each other by a distance d1. Thus, for example, even if d2 is greater than D, the final stress on the valve is small compared to the cylindrical suction orifice.

With the structure of the present invention for the suction orifice, a reduction in the maximum bending stress of the suction valve vane in the region of the suction orifice is obtained, compared to the maximum stress foreseen at the cylindrical orifice, thereby enabling the use of a valve vane of small thickness, The loss of power in this element during inhalation is reduced and the efficiency is increased.

Claims (10)

A suction and discharge valve device for a small hermetic compressor including a compression cylinder (1), the suction and discharge valve device comprising a suction pipe (5) and a valve plate (10), wherein the compression cylinder (1) , In use, has an end closed by the valve plate 10 and supplied with gas by the suction pipe 5, the suction pipe 5 being disposed adjacent to the valve plate 10, In the intake and discharge valve device for a small hermetic compressor orthogonal to the axis of the compression cylinder, The valve plate 10 has a discharge orifice 11 which is disposed in the center with respect to the axial protrusion 20 of the inner contour of the compression cylinder 1, and the inner contour of the compression cylinder 1, in use. It has at least one suction orifice 12 located inside the axial protrusion 20 outside the contour of the discharge orifice 11, the at least one suction orifice 12, the discharge orifice ( Occupies an annular fan shape concentrically formed with at least one of the inner contours of the compression cylinder 1 and the discharge orifice 11 so as to maintain a constant minimum distance from 11) and forms at least part of the suction passage P And the suction passage P is opened by the gas discharge end 12b opened into the compression cylinder 1 and the suction pipe 5 and is opened by the transition portion T. On the opposite side connected to (5) And a transition portion T, which is provided in one of the portions formed by the suction passage P and the suction pipe 5, changes the direction of the gas flow so that the suction The internal shape of the orifice 12 is at least partially curved so that the entire cross section of the orifice 12 can be used completely in the gas flow passage, and the gas introduction end 12a has a cross section larger than the cross section of the gas discharge end 12b. Inlet and outlet valve device for a compact hermetic compressor, characterized in that. 2. A suction and discharge valve device for a compact hermetic compressor according to claim 1, characterized in that the transition portion (T) forms a duct portion connecting the suction pipe (5) to the suction passage (P). The suction and discharge valve device according to claim 2, wherein the transition portion (T) is provided in the suction passage (P). 4. A suction and discharge valve device for a compact hermetic compressor according to claim 3, wherein the suction passage (P) is formed by the suction orifice (12) itself. 5. The compact as claimed in claim 4, wherein the transition portion (T) is formed by the gas introduction end (12a) of the suction orifice (12) in which a portion of the contour is bent to form a shape for gas introduction. Inlet and outlet valve devices for hermetic compressors. 5. The valve plate (10) according to claim 4, wherein an intake valve vane (30) is attached at one end portion (31) thereof on its face facing the interior of the compression cylinder. The other end portion 32) is displaced between the closed valve position blocking the suction orifice 12 and the open valve position opening the suction orifice 12 by the elastic deformation of its suction valve vane, and the suction valve And the vane 30 is located on the outside of the axial projection of the contour of the discharge orifice 11 inside the axial projection 20 of the inner contour of the compression cylinder 1. Discharge valve device. 7. The area of the valve plate (10) according to claim 6, wherein the end portions (31, 32) of the intake valve vanes (30) are on opposite sides and opposite to the discharge orifice (11). Inlet and outlet valve device for a compact hermetic compressor, characterized in that located. 8. A suction and discharge valve arrangement for a compact hermetic compressor according to claim 7, characterized in that the suction valve vanes (30) have an "U" contour. 2. A suction and discharge valve device for a compact hermetic compressor according to claim 1, wherein the suction orifice (12) has an annular fan shape. 2. A suction and discharge valve arrangement according to claim 1, characterized in that the discharge orifice (11) is circular and coaxial with the inner contour of the compression cylinder (1).

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