KR102239817B1 - Turbo Compressor - Google Patents

Abstract

An embodiment of the present invention relates to a turbo compressor. According to one aspect, the turbo compressor comprises: a casing; a driving unit which is provided in an inner space of the casing, and generates rotational force; a rotary shaft which is installed to pass through the casing, and transmits the rotational force generated by the driving unit; a shaft motion sensor formed to detect a displacement of the rotary shaft; a compression unit which rotates together with the rotary shaft, and includes an impeller for compressing a withdrawn fluid; an axial support plate coupled to the rotary shaft and positioned adjacent to the driving unit; a thrust bearing which is installed in the casing, and supports the axial support plate; a piezoelectric sensor which is attached to one side surface of the thrust bearing, and generates a voltage by deformation according to the pressure applied to the thrust bearing; and a control unit which compares a voltage value generated by the piezoelectric sensor with a set reference value, determines that there is a fluctuation when the voltage value is greater than or equal to a predetermined value, and controls the rotational force of the driving unit. According to the present invention, the turbo compressor can enhance compression efficiency.

Description

Turbo Compressor {Turbo Compressor}

This embodiment relates to a turbo compressor.

In general, compressors can be largely divided into positive displacement compressors and turbo compressors. The positive displacement compressor uses a piston or vane, such as a reciprocating type or a rotary type, in which fluid is sucked, compressed, and then discharged. On the other hand, a turbo-type compressor uses a rotating element to inhale, compress, and then discharge fluid.

The positive displacement compressor determines the compression ratio by appropriately adjusting the ratio of the suction volume and the discharge volume to obtain the desired discharge pressure. Therefore, the positive displacement compressor is limited in miniaturizing the overall size relative to its capacity.

The turbo-type compressor is similar to a turbo blower, but has a higher discharge pressure and a lower flow rate than a turbo blower. These turbo-type compressors increase pressure in a fluid that continuously flows, and are classified into an axial flow type when the fluid flows in the axial direction, and a centrifugal type when the fluid flows in a radial direction.

On the other hand, unlike positive displacement compressors such as reciprocating compressors and rotary compressors, turbo compressors achieve the desired high pressure ratio with only one compression due to various factors such as workability, mass production, and durability even if the blade shape of the rotating impeller is optimally designed. It is difficult. Accordingly, a multi-stage turbocompressor is known that compresses a fluid in multiple stages by providing a plurality of impellers in the axial direction.

Such a multi-stage turbocompressor may have a form in which a plurality of impellers are disposed opposite to each other with respect to a rotation shaft (first form), or a form in which a plurality of impellers are sequentially disposed at one end of the rotation shaft (second form).

In the case of the first form, there is an advantage that the thrust directions of the plurality of impellers are opposite to each other, so that the axial fluctuation can be suppressed to a certain degree, but there is a problem that the structure inside the compressor for connecting the plurality of impellers is complicated. have.

In the case of the second form, there is an advantage that the structure inside the compressor is simplified because the pipe or fluid passage connecting the plurality of impellers is shortened, but the thrust direction between the plurality of impellers forms the same direction, so there is a problem that the axial fluctuation increases. have.

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Korean Patent Application Publication No. 10-2018-0082894 (published on July 19, 2019)

The present invention has been proposed in order to improve the above problems, and is to provide a turbo compressor capable of improving compression efficiency by shortening the length of a pipe or passage connecting a plurality of impellers.

The turbo compressor according to the present embodiment includes a casing; A driving unit provided in the inner space of the casing to generate a rotational force; A rotation shaft installed to pass through the casing and transmitting a rotational force generated by the driving unit; A shaft motion sensor formed to sense the displacement of the rotation shaft; A compression unit that rotates with the rotation shaft and includes an impeller for compressing the sucked fluid; An axial support plate coupled to the rotation shaft and positioned adjacent to the driving unit; A thrust bearing installed on the casing to support the axial support plate; A piezoelectric sensor attached to one side of the thrust bearing and generating a voltage by deformation according to a pressure applied to the thrust bearing; And a controller configured to compare the voltage value generated by the piezoelectric sensor with a set reference value, and when the voltage value is greater than or equal to a certain value, determine the vibration as a vibration and control the rotational force of the driving unit.

According to the present embodiment, a separate back pressure space is formed on the rear surface of the impeller and a high-pressure refrigerant is supplied to the back pressure space, so that even if the thrust of the impeller is increased by rotating the drive unit at high speed, the impeller is moved backward by the thrust. It can effectively stop being pushed back.

1 is a cross-sectional view of a turbo compressor according to an embodiment of the present invention.
FIG. 2 is an enlarged view of A in FIG. 1;
3 is a cross-sectional view showing a modified example of FIG. 2.
4 to 6 are cross-sectional views showing an operation state of a back pressure valve according to a pressure of a refrigerant flowing into the valve space through a back pressure flow path in a turbo compressor according to an embodiment of the present invention and a flow state of the refrigerant accordingly.
7 is a diagram showing a sensor module (eg, a piezoelectric sensor and a temperature sensor) applied to a thrust bearing of a turbo compressor according to an embodiment of the present invention.
8 is an exemplary view showing an output voltage value of a piezoelectric sensor due to a pressure applied to a thrust bearing according to an embodiment of the present invention.
9 is a flowchart showing a method of controlling a turbo compressor according to an embodiment of the present invention
10 is a conceptual diagram of a shaft motion sensor according to an embodiment of the present invention.
11 is a conceptual diagram showing the principle of displacement detection by the non-contact sensor shown in FIG.
12 is an enlarged view of B in FIG. 1;
13 is a flowchart showing a method of controlling the turbo compressor of the present invention by the control unit shown in FIG. 10;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical idea of the present invention is not limited to some embodiments to be described, but may be implemented in various different forms, and within the scope of the technical idea of the present invention, one or more of the constituent elements may be selectively selected between the embodiments. It can be combined with and substituted for use.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention are generally understood by those of ordinary skill in the art, unless explicitly defined and described. It can be interpreted as a meaning, and terms generally used, such as terms defined in a dictionary, may be interpreted in consideration of the meaning in the context of the related technology.

In addition, terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention. In the present specification, the singular form may include the plural form unless specifically stated in the phrase, and when described as “at least one (or more than one) of A and (and) B and C”, it is combined with A, B, and C. It may contain one or more of all possible combinations.

In addition, terms such as first, second, A, B, (a), and (b) may be used in describing the constituent elements of the embodiment of the present invention.

These terms are only for distinguishing the constituent element from other constituent elements, and are not limited to the nature, order, or order of the constituent element by the term.

And, when a component is described as being'connected','coupled' or'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also the component It may also include a case of being'connected','coupled', or'connected' due to another component between the and the other component.

In addition, when it is described as being formed or disposed on the "top (top) or bottom (bottom)" of each component, the top (top) or bottom (bottom) is not only when the two components are in direct contact with each other, but also It also includes the case where one or more other components are formed or disposed between the two components. In addition, when expressed as "upper (upper) or lower (lower)", the meaning of not only an upward direction but also a downward direction based on one component may be included.

1 is a cross-sectional view of a turbo compressor according to an embodiment of the present invention, FIG. 2 is an enlarged view of A in FIG. 1, and FIG. 3 is a cross-sectional view showing a modified example of FIG. 2, and FIGS. 4 to 6 are A cross-sectional view showing an operation state of a back pressure valve according to a pressure of a refrigerant flowing into the valve space through a back pressure flow path and a flow state of the refrigerant according to the turbo compressor according to an embodiment of the present invention.

1 to 6, in the turbo compressor according to this embodiment, the driving unit 120 is installed in the inner space of the casing 110, and the first compression unit 130 and the first compression unit 130 are external to the casing 110. 2 A compression unit 140 is installed, and is connected between the driving unit 120 and the compression units 130 and 140 by a rotating shaft.

The casing 110 may include a shell 111 formed in a cylindrical shape by opening both ends, and a front frame 112 and a rear frame 113 respectively covering both open ends of the shell 111.

The stator 121 of the driving unit 120, which will be described later, is fixedly coupled to the inner circumferential surface of the shell 111, and a rotation shaft 125 to be described later is passed through the center of the front frame 112 and the rear frame 113. Each of the grooves 112a and 113a is formed, and radial bearings 151 that support the rotating shaft in the radial direction are formed in the shaft hole 112a of the front frame 112 and the shaft hole 113a of the rear frame 113. ) 152 may be installed respectively.

In addition, a first thrust bearing 153 is coupled to an inner surface of the front frame 112 and a second thrust bearing 154 is coupled to the inner surface of the rear frame 113, respectively, and a first thrust bearing 154 is coupled to the rotation shaft 125 to be described later. The first axial support plate 161 and the second axial support plate 162 may be fixedly coupled to each other to face the thrust bearing 153 and the second thrust bearing 154, respectively.

That is, the first thrust bearing 153 forms a first-direction thrust limiting portion together with the first axial support plate 161, and the second thrust bearing 154 together with the second axial support plate 162 It forms a thrust limiting part. Accordingly, the first direction thrust limiting unit and the second direction thrust limiting unit form a thrust bearing in opposite directions to each other, thereby canceling the thrust force on the rotating element including the rotating shaft 125.

Meanwhile, the driving unit 120 serves to generate power for compressing the refrigerant. The driving unit 120 includes a stator 121 and a rotor 122, and at the center of the rotor 122, the rotational force of the rotor 122 is converted to a first impeller 131 and a second impeller 141 to be described later. A rotating shaft 125 for transmitting is coupled.

The stator 121 may be fixed by press-fitting to the inner circumferential surface of the casing 110 or welded to the casing 110 to be fixed. The outer circumferential surface of the stator 121 is formed to be de-cut, so that a passage through which the fluid can move may be formed between the inner circumferential surface of the casing 110.

The rotor 122 is located inside the stator 121 and is spaced apart from the stator 121. A balance weight for canceling an eccentric load generated by the first impeller 131 and the second impeller 141 to be described later may be coupled to both ends of the rotor 122 in the axial direction. However, the balance weight may not be installed on the rotor and may be coupled to the rotating shaft.

When the balance weight is coupled to the rotating shaft, the first axial support plate 161 and the second axial support plate 162 may be used as a balance weight.

The rotation shaft 125 is press-fitted through the center of the rotor 122. Therefore, the rotation shaft 125 receives rotational force generated by the interaction between the stator 121 and the rotor 122 and rotates together with the rotor 122, and this rotational force is the first impeller 131 and the second impeller to be described later. It is delivered to 141 to suck, compress and discharge the refrigerant.

In addition, a first axial support plate supported in the axial direction by first and second thrust bearings 153 and 154 provided in the casing 110 on both sides of the rotation shaft 125, that is, both sides of the rotor 122 161 and the second axial support plate 162 are fixedly coupled, respectively. Accordingly, the rotation shaft 125 includes a first axial support plate 161 and a second axial support plate 162 provided on the rotation shaft 125 as described above, and a first thrust bearing provided on the casing 110 ( While being supported in opposite directions by the 153 and the second thrust bearing 154, the thrust generated by the first compression unit 130 and the second compression unit 140 can be effectively canceled out.

Further, the first axial support plate 161 and the second axial support plate 162 may be integrally provided at both ends of the rotor 122, but in this case, the first axial support plate 161 and the second axial support plate Friction heat generated in the process of supporting the rotating shaft 125 in the axial direction 162 may be transferred to the rotor 122, and when each of the supporting plates 161 and 162 is deformed by receiving a load in the axial direction, the rotor 122 can be modified. Accordingly, the first axial support plate 161 and the second axial support plate 162 may be spaced apart from both ends of the rotor 122, respectively.

In addition, when the first axial support plate 161 and the second axial support plate 162 are fixedly coupled to the rotation shaft 125 to be described later, as described above, the first axial support plate 161 and the second axial support plate It can also be used as a balance weight by adjusting the weight or fixed position of the 162. In this case, since it is not necessary to install a separate balance weight on the rotor, not only the weight of the rotating element can be reduced by that amount, but also the axial length of the turbo compressor can be reduced, so that the turbo compressor can be miniaturized.

Here, the first thrust bearing 153 and the second thrust bearing 154 are not installed on the front frame 112 and the rear frame 113, but are opposite to the first axial support plate 161 and the second shaft. It may be installed on the directional support plate 162.

The compression unit may be formed of one compression unit to perform a single compression, but may be formed of a plurality of compression units to perform multi-stage compression as in the present embodiment. In the case of multi-stage compression, it is preferable in terms of reliability that a plurality of compression units 130 and 140 are installed on both sides of the casing 110 based on the drive unit 120, considering the characteristics of the turbo compressor having a large axial load. I can. However, in the case of the opposite type in which a plurality of compression units are installed on both sides, as mentioned above, the length of the compressor may be lengthened and the compression efficiency may be reduced. Forming on one side as a reference may be desirable in terms of high efficiency and miniaturization. Hereinafter, when a plurality of compression units are provided to compress the refrigerant in multiple stages, a description will be made by dividing into first and second compression units according to the order of compressing the refrigerant.

The first compression unit 130 and the second compression unit 140 are installed in succession along the axial direction at one side of the casing 110.

In the first compression unit 130 and the second compression unit 140, each impeller 131 and 141 may be accommodated and coupled to each of the impeller housings 132 and 142. That is, in the first compression unit 130, the first impeller 131 is accommodated in the first impeller housing 132 and coupled to the rotating shaft 125, and the second compression unit 140 has the second impeller 41 It may be accommodated in the second impeller housing 142 and coupled to the rotation shaft 125.

A first impeller receiving space (132a) in which the first impeller 131 is accommodated is formed inside the first impeller housing 132, and a suction pipe 115 is connected to one end of the first impeller housing 132 to provide a refrigeration cycle. A first inlet 132b through which the refrigerant is sucked from the evaporator of is formed, and at the other end of the first impeller housing 132, a first outlet 132c for guiding the compressed refrigerant in the first stage to the second impeller housing 142 to be described later. ) Is formed.

The first impeller accommodation space 132a may be formed in a closed shape except for the first inlet 132b and the first outlet 132c so that the first impeller 131 can be fully received, but the first impeller 131 It may be formed in a semi-hermetic shape in which the rear side of is opened and the open side is sealed to the front side of the second impeller housing 142 to be described later.

A first diffuser 133 is formed between the first inlet 132b and the first outlet 132c by spaced apart from the outer circumferential surface of the wing portion 131b of the first impeller 131 by a predetermined distance, and the first diffuser 133 A first volute 134 is formed on the downstream side of ). In addition, a first inlet 132b is formed at the center of one end in the axial direction of the first diffuser 133 and a first outlet 132c is formed at a downstream side of the first volute 134.

The first impeller 131 includes a first disk portion 131a coupled to the rotation shaft 125 and a plurality of first blade portions 131b formed on the front surface of the first disk portion 131a. The first disk portion 131a has a plurality of first wing portions 131b formed in a conical shape on the front surface thereof, but the rear surface thereof may be formed in a flat plate shape to receive back pressure.

Here, a first back pressure plate (not shown) coupled to the rotation shaft 125 is provided at a predetermined distance apart from the rear of the first disk portion 131a, and the first back pressure plate has a first sealing member having an annular shape. (Not shown) may be provided. Accordingly, a first back pressure space (not shown) filled with a predetermined refrigerant may be formed between the front surface of the second impeller housing and the first back pressure plate, which will be described later, at the rear of the first disc portion.

A second impeller accommodation space 142a in which the second impeller 141 is accommodated is formed inside the second impeller housing 142, and at one end of the second impeller housing 142, the first impeller housing 132 A second inlet 142b connected to the first outlet 132c to suck the first-stage compressed refrigerant is formed, and a discharge pipe 116 is connected to the other end of the second impeller housing 142 to transfer the second-stage compressed refrigerant. A second outlet 142c that guides to the condenser of the refrigeration cycle is formed.

A second diffuser 143 is formed between the second inlet 142b and the second outlet 142c by spaced apart from the outer circumferential surface of the wing portion 141b of the second impeller 141 by a predetermined distance, and the second diffuser 143 A second volute 144 is formed on the downstream side of ). In addition, a second inlet 142b is formed at the center of one end in the axial direction of the second diffuser 143 and a second outlet 142c is formed at a downstream side of the second volute 144, respectively.

Meanwhile, the diameter D2 of the second inlet 142b may be smaller than the diameter of the first inlet D1. Accordingly, the refrigerant flowing into the second impeller housing 142 may be compressed to a higher pressure while flowing into the second inlet 142b.

The second impeller 141 includes a second disk portion 141a coupled to the rotation shaft 125 and a plurality of second blade portions 141b formed on the front surface of the second disk portion 141a. The second disk portion 141a has a plurality of second wing portions 141b formed in a conical shape on the front surface thereof, but the rear surface thereof may be formed in a flat plate shape to receive back pressure.

Here, a second back pressure plate 145 coupled to the rotation shaft 125 is provided at the rear of the second disc portion 141a spaced apart by a predetermined interval, and the second back pressure plate 145 has an annular shape. A groove 145a is formed so that the second sealing member 146 may be inserted into the second sealing groove 145a. Accordingly, a second back pressure space 147 filled with a predetermined refrigerant is formed between the second back pressure plate 145 and the front surface of the casing 110 at the rear of the second disk portion 141a. And, as a part of the refrigerant flowing into the second back pressure space 147 flows into the second sealing groove 145a and pushes the second sealing member 146 up, the second sealing member 146 becomes the front frame It is in close contact with the front surface of 112 to seal the second back pressure space 147.

The second back pressure space 147 is connected to a back pressure flow path 171 to be described later, and the pressure of the second back pressure space 147 is in the back pressure flow path according to the operating speed (ie, compression ratio) of the compressor. A back pressure control valve 173 may be installed to selectively open and close the back pressure flow path 171 so that the pressure of the back pressure can be varied.

For example, as shown in FIG. 4, the back pressure flow path 171 may be formed through the inside of the second impeller housing 142 and the casing 110. That is, the first back pressure flow path 171a is formed in the housing forming the wall of the second impeller housing 142, and the first back pressure flow path 171a and the inside of the front frame 112 of the casing 110 A second back pressure flow path 171b to be communicated may be formed.

Of course, the back pressure flow path 171 may be formed in the form of a pipe branched in the middle of the discharge pipe 116, but the back pressure flow path 171 formed inside the impeller housing and the front frame reduces the number of parts and reduces the manufacturing cost. It may be desirable to be able to save.

A valve space 172 having a predetermined depth in the radial direction is formed in the front frame 112 of the casing 110, and a first back pressure hole to be described later while sliding in the valve space 172 A back pressure valve 173 for selectively opening and closing the second back pressure hole 172b is inserted, and a valve for elastically supporting the back pressure valve 173 between the valve space 172 and the back pressure valve 173 A spring 174 may be installed.

The valve space 172 is formed to be depressed by a predetermined depth from the outer circumferential surface of the front frame 112 of the casing 110 to the inner circumferential surface, and in the middle of the valve space 172, the valve space 172 is provided with a back pressure space ( A first back pressure hole 172a communicating with the 147 is formed. The first back pressure hole 172a may be formed to be smaller than or equal to the inner diameter of the valve space 172.

In addition, a second back pressure hole 172b for communicating the valve space 172 with the inner space of the casing 110 may be formed at one side of the first back pressure hole 172a. The second back pressure hole 172b is the first back pressure hole 172b so that it can be opened when it receives a higher pressure than the first back pressure hole 172a when the back pressure valve 173 is opened by pressure. It is formed so as to be located inside the rotation shaft 125 than the back pressure hole 172a.

The back pressure valve 173 may be formed of a ball valve or a piston valve. The back pressure valve 173 may have three positions according to a difference between the force due to the pressure of the refrigerant flowing through the back pressure flow path 171 and the force due to the elastic force of the elastic member.

That is, the back pressure valve 173 is a first position where both the first back pressure hole 172a and the second back pressure hole 172b are closed, the first back pressure hole 172a is opened, and the second back pressure hole 172b is closed. It may be formed to have a position and a third position in which both the first back pressure hole 172a and the second back pressure hole 172b are opened.

To this end, the valve spring 174 may be made of a compression coil spring and may be installed between the inner surface of the back pressure valve 173 and the valve space 172, and in some cases, the valve spring 174 is a tension coil spring. It may be installed between the outer side of the back pressure valve 173 and the valve space 172.

Meanwhile, in the above-described embodiment, the first back pressure passage 171a is connected to the discharge side of the second compression unit 140, that is, the second outlet 142c, but in some cases, the back pressure passage 171 as shown in FIG. 5 May be connected to the discharge side of the first compression unit 130. Even in this case, the basic configuration such as the valve space 172 and the back pressure valve 173 may be formed in the same manner as in the above-described embodiment.

The turbo compressor according to the present embodiment as described above can be operated as follows.

When power is applied to the driving unit 120, a rotational force is generated by an induced current between the stator 121 and the rotor 122, and the rotational shaft 125 rotates with the rotor 122 by this rotational force. .

Then, the rotational force of the driving unit is transmitted to the first impeller 131 and the second impeller 141 by the rotation shaft 125, and the first impeller 131 and the second impeller 141 are each impeller accommodation space ( It rotates at the same time at 132a and 142a.

Then, the refrigerant that has passed through the evaporator of the refrigeration cycle flows into the first impeller accommodation space (132a) through the suction pipe and the first inlet (132b), and the refrigerant moves along the wing portion (131b) of the first impeller (131). While the static pressure rises, it passes through the first diffuser 133 with a centrifugal force at the same time.

Then, the refrigerant passing through the first diffuser 133 causes the kinetic energy to rise due to the centrifugal force in the first diffuser 133, and the centrifugally compressed high-temperature, high-pressure refrigerant in the first volute 134 It is collected and discharged through the first outlet (132c).

Then, the refrigerant discharged from the first outlet (132c) is transferred to the second impeller 141 through the second inlet (142b) of the second impeller housing 142, and the positive pressure inside the second impeller (141) again. This rises and at the same time passes through the second diffuser 143 with a centrifugal force. The refrigerant passing through the second diffuser 143 is compressed to a desired pressure by centrifugal force, and the two-stage compressed high-temperature, high-pressure refrigerant is collected in the second volute 144, and the second outlet 142c and the discharge pipe 116 are collected. ) Through a series of processes that are discharged to the condenser is repeated.

At this time, the first impeller 131 and the second impeller 141 are thrust pushed to the rear by the refrigerant sucked through the first inlet 132b and the second inlet 142b of each impeller housing 132 and 142 You will receive. In particular, in the case of the second impeller 141, as the refrigerant compressed in one stage by the first impeller 131 flows through the second inlet 142b, it receives a considerably large rear thrust. In particular, considering that the diameter D2 of the second inlet 142b is smaller than the diameter D1 of the first inlet 132b, the second impeller 141 receives a stronger thrust.

This backward thrust is prevented by the first thrust bearing 153 and the second thrust bearing 154 provided inside the casing 110, so that the first impeller 131 and the second impeller 141 are rotated by the shaft 125 ) And is suppressed from being pushed backwards.

However, as described above, when the first impeller 131 and the second impeller 141 are installed on one side based on the driving unit, they receive a considerably large thrust toward the rear in the axial direction, thereby increasing the cross-sectional area of the thrust bearing. It must be secured to maintain the reliability of the compressor. However, this may increase the size of the turbocompressor as well as increase the friction loss in the thrust bearing, thereby reducing the compressor efficiency.

In consideration of this, as in this embodiment, a separate back pressure space 147 is formed on the rear side of the first impeller 131 and the second impeller 141, especially on the rear side of the second impeller 141, and the back pressure When the high-pressure refrigerant compressed in one or two stages is supplied to the space 147 to suppress the second impeller 141 from being pushed to the rear side, the load applied to the thrust bearing can be reduced. Then, the size of the thrust bearing can be reduced, and the friction loss caused by the thrust bearing can be reduced, thereby increasing the compressor efficiency.

In addition, the amount of heat generated from the driving unit 120 may increase during high-speed operation, but when the driving unit 120 is cooled by inducing a part of the bypassed refrigerant into the inner space of the casing 110, the driving unit 120 ), the efficiency of the compressor can be improved.

That is, referring to Figs. 4 to 6, the high-pressure refrigerant compressed in two stages by the second impeller 141 is discharged to the discharge pipe 116 through the second outlet 142c. Some of the high-pressure refrigerant before being discharged or discharged through the discharge pipe is bypassed to the back pressure flow path 171 and flows into the valve space 172, and the refrigerant flowing into the valve space 172 passes through the back pressure valve 173. It is pushed inward.

At this time, as shown in FIG. 4, when the rotational speed of the driving unit 120 reaches a low first speed, the pressure ratio of the second compression unit becomes lower than the reference pressure ratio (a pressure that exerts a force equal to the elastic force of the valve spring). Then, the force due to the pressure of the refrigerant compressed by the second impeller 141 becomes smaller than the force due to the elastic force of the valve spring 174, and the back pressure valve 173 is pushed by the elastic force of the valve spring 174 The position (P1) is maintained.

Then, both the first back pressure hole 172a and the second back pressure hole 172b are closed, and the rotation shaft including the first impeller 131 and the second impeller 141 is the first thrust bearing 153 and the second thrust. The axial thrust is blocked only by the bearing 154. However, in this case, since the rotational speed of the driving unit 120 is not high, the pressure of the refrigerant sucked toward the inlets of the first impeller 131 and the second impeller 141 is not high, so that the first thrust bearing 153 And even if the area of the second thrust bearing 154 is not large, it is possible to sufficiently prevent the thrust.

On the other hand, if the rotational speed of the driving unit 120 is higher than the first speed, but the force due to the pressure of the refrigerant by the second impeller 141 becomes a second speed greater than the force due to the elastic force of the valve spring 174, the casing The combined force of the pressure (internal pressure) formed in the inner space of 110 and the elastic force by the valve spring 174 is higher than the pressure by the second impeller 141 and moves to the second position P2.

Then, while the first back pressure hole 172a is opened and the second back pressure hole 172b is closed, the high-pressure refrigerant bypassed to the back pressure flow path 171 is passed through the first back pressure hole 172a to the back pressure space 147 And the pressure in the back pressure space 147 is increased by the refrigerant flowing into the back pressure space 147, and the second impeller 141 is pushed backward in the axial direction by supporting the second back pressure plate 145. It will prevent you from doing it. In this case, as the back pressure of the back pressure space 147 is suppressed from being pushed to the rear side, the rotation shaft 125 including the second impeller 141 together with the first thrust bearing 153 and the second thrust bearing 154 is suppressed, As such, even if the first thrust bearing 153 and the second thrust bearing 154 are formed in a small area, the rotation shaft 125 including the second impeller 141 can be stably supported.

On the other hand, the first back pressure hole 172a is formed in a shape in which the cross-sectional area increases from the second compression unit 140 to the driving unit 120, so that the refrigerant in the back pressure space 147 goes back to the valve space 172. It can prevent backflow. That is, an inclined surface having a cross-sectional area increasing from the second compression unit 140 to the driving unit 120 may be formed on the inner circumferential surface of the first back pressure hole 172a.

On the other hand, when the operating speed of the driving unit 120 is a third speed that is greater than the second speed, the force due to the pressure of the refrigerant compressed by the second impeller 141 is the internal pressure of the casing 110 and the valve spring ( It is greater than the sum of the elastic force of 174, and accordingly, the back pressure valve 173 is pushed to the third position P3 by the refrigerant flowing into the valve space 172 through the back pressure flow path. All of the 2 back pressure holes 172b are opened.

Then, the high-pressure refrigerant moves to the back pressure space 147 to increase the pressure in the back pressure space 147 to support the rear surface of the second impeller 141 to the front, and accordingly, the first thrust bearing 153 and Even if the area of the second thrust bearing 154 is slightly reduced, it is possible to effectively prevent the rotation shaft 125 including the first impeller 131 and the second impeller 141 from being pushed backward in the axial direction.

At the same time, a high-pressure refrigerant flows into the inner space of the casing 110 through the second back pressure hole 172b, and the refrigerant flows through the gas through hole 161a provided in the first axial support plate 161. Since the inner space of 110) is circulated, the inner space of the casing 110 is cooled.

Then, it is possible to improve compressor performance by effectively attenuating overheating of the driving unit 120 that may occur when the load of the driving unit 120 is increased.

In this way, as a separate back pressure space is formed on the rear surface of the impeller and a high-pressure refrigerant is supplied to the back pressure space, the impeller is prevented from being pushed backward by the thrust even though the drive unit rotates at high speed and the thrust of the impeller increases. It can be effectively prevented.

In addition, the load of the thrust bearing can be reduced by canceling or attenuating the thrust received by the impeller by using the back pressure of the back pressure space, and accordingly, the area of the thrust bearing can be reduced. It can be possible.

Hereinafter, a turbocompressor that applies a piezoelectric sensor including a piezoelectric element to a thrust bearing in a turbocompressor, and detects abnormal motion of the turbocompressor due to surge or resonance based on voltage fluctuations of the piezoelectric element. Let's explain.

When an abnormal motion (abnormal behavior) of the turbo compressor caused by surge or resonance in the turbo compressor according to the present invention is detected, the operation of the turbo compressor is changed (for example, the speed of the turbo compressor is reduced), Operation stability of the turbo compressor can be secured.

In addition, a temperature sensor as well as a piezoelectric element is applied to the thrust bearing in the turbocompressor, and a fault diagnosis of the thrust bearing is made based on the temperature change value of the temperature sensor (for example, if the temperature of the thrust bearing rises abnormally, this Recognize) can be performed.

In the case of a turbo compressor, unlike a positive displacement compressor, the speed of the fluid by the rotational speed of the impeller changes into pressure. Accordingly, the turbo compressor must be operated at high speed to increase the pressure ratio, and accordingly, the turbo compressor may become unstable. For example, due to compression instability that occurs when the impeller of a turbo compressor is rotated at high speed to increase the speed of a fluid, a surge phenomenon in which suction and discharge flows are unstable may occur. In addition, due to the characteristics of the rotating body supported by the elastic bearing in the dynamics of the rotating body of the turbocompressor, a resonance phenomenon may occur in which the rotating body revolves in the same or opposite to the rotation direction (rotation) at the resonance point.

In the present invention, a sensor module (for example, a piezoelectric sensor and a temperature sensor) in the first thrust bearing 153 and the second thrust bearing 154 that vertically supports the upper and lower ends of the rotating shaft (shaft, 125) ( Refer to the reference numeral 300 in Fig. 7) is attached.

A sensor module (for example, a piezoelectric sensor and a temperature sensor) (see reference numeral 300 in FIG. 7) includes a first thrust bearing 153 and a second thrust bearing vertically supporting the upper and lower ends of the rotating shaft (shaft) 125. All may be attached to the thrust bearing 154.

7 shows a sensor module (for example, a piezoelectric sensor and a temperature sensor) applied to a thrust bearing of a turbo compressor according to an embodiment of the present invention, among the first thrust bearing 153 and the second thrust bearing 154 A sensor module (eg, a piezoelectric sensor and a temperature sensor) attached to the second thrust bearing 154 is shown.

The thrust bearing 154 according to the embodiment of the present invention may be a foil bearing. Foil bearings (154) support the rotation of ultra-high-speed rotating bodies such as turbo compressors, turbo blowers, turbochargers, and small gas turbines, while maintaining non-contact with the shaft during high-speed rotation to minimize friction and wear and to minimize lubrication. There is no need for a system, heat generation and noise are low, and the structure of the system is relatively simple.

As shown in Fig. 7, the foil bearing 154 includes a top foil 154a, a bump foil 154b, and a bump block 154c.

The top foil 154a has one end attached to a bump block 154c, and is formed to have a constant inclination in a direction in close contact with the axial support plate from one end to the other.

The top foil (154a) is made to include a flat portion, an inclined portion, and a fixing portion, and the flat portion is fixed to a bump block (154c), and the inclined portion and the fixing portion are spaced apart from the bump foil (154b) by a certain distance. It is made in the shape of a cantilever that is positioned to be

The flat part is fixed to the bump block 154c, the inclined part is a part formed to have a predetermined angle, and the fixed part refers to a part that extends to have a certain distance from the thrust runner.

The bump foil 154b is disposed under the top foil 154a and may be made of an elastic material.

The bump block 154c is installed on one surface of the foil bearing 154 and may be fixedly installed along the radial direction at regular intervals.

The piezoelectric sensor and the temperature sensor 300 are attached along the inclined portion, and one side of the piezoelectric sensor 300 is fixed by the fixing portion and the bump block 154c.

The bump foil 154b is made of an elastic material in the form of embossing, and the elastic material in the form of embossing has a certain height in the section of the flat section of the top foil 154a. It may be formed with a height gradually lowering than the height in the section.

A bump block (154c) is for fixing one side of the piezoelectric sensor and the temperature sensor 300, and the piezoelectric sensor and temperature between the fixing part of the top foil 154a and the bump block 154c One side of the sensor 300 may be inserted and fixed. The piezoelectric sensor and the temperature sensor 300 are fixed by a fixing portion of the top foil 154a and a bump block 154c, and are attached to the inclined portion of the top foil 154a.

The bump block 154c is disposed to overlap the fixed portion and the inclined portion of the top foil 154a in the vertical direction, and the piezoelectric sensor and the temperature sensor 300 are between the bump block 154c and the fixed portion, and the bump block 154c It is interposed between the and the inclined part. The upper surface of the bump block 154c may support the lower surface of the piezoelectric sensor and the temperature sensor 300, and the lower surface may be elastically supported by the upper surface of the bump foil 154b.

The top foil 154a may be made of an elastic material, and may be restored again after being deformed by the pressure applied to the top foil 154a.

When the thrust runner 162 rotates at high speed, an air layer (Gas film, 301) is created between the top foil (154a) and the thrust runner 162, and the thrust runner 162 is formed on the gas film (301). As a result, it rotates at high speed without contacting the top foil 154a.

The unstable behavior of the turbocompressor occurs due to a surge or resonance phenomenon, which causes the thrust runner 162 to oscillate and apply pressure to the piezoelectric sensor attached to the slope of the top foil 154a, and the piezoelectric sensor The voltage value (displacement) that varies according to is output to the control unit (503 in FIG. 1).

A temperature sensor attached to the slope of the top foil 154a, such as a piezoelectric sensor, measures the current temperature value of the foil bearing 154 in real time, and transmits the measured current temperature value to the control unit (503 in FIG. 1). Output in real time.

A plurality of piezoelectric sensors may be attached at different positions within the inclined portion of the top foil 154a. The piezoelectric sensor may be attached to a maximum deformation point generated while the top foil 154a supports the thrust runner 162.

Hereinafter, when an abnormal motion (abnormal behavior) of the turbo compressor caused by a surge or resonance in the turbo compressor is detected, the operation of the turbo compressor is changed (for example, the speed of the turbo compressor is reduced). A turbo compressor capable of ensuring the operation stability of the compressor will be described with reference to FIGS. 1 and 7.

As shown in Figure 1, the turbo compressor according to the embodiment of the present invention further includes a control device, the control device, a piezoelectric sensor and a temperature sensor 300 attached to the thrust bearing 154, the piezoelectric sensor 300 ), based on the output voltage value and the reference value, detects abnormal fluctuation of the turbocompressor caused by surge or resonance, and controls the rotational force of the drive unit 120 based on the detected fluctuation. do.

The control device may further include a filter 501 for filtering a voltage value output from the piezoelectric sensor 300 attached to the thrust bearing 154. For example, the filter 501 removes noise included in the voltage value output from the piezoelectric sensor 300 attached to the thrust bearing 154, and outputs the voltage value from which the noise is removed to the controller 503 It plays a role.

The control device amplifies a voltage signal (voltage value) output from the filter 501 as well as a filter 501 that filters a voltage value output from the piezoelectric sensor 300 attached to the thrust bearing 154, An amplifier 502 for outputting the amplified voltage signal (voltage value) to the controller 503 may be further included.

The control unit 503 compares the output voltage value of the piezoelectric sensor 300 with a reference value, and when the output voltage value of the piezoelectric sensor 300 exceeds the reference value, abnormal fluctuation of the turbocompressor caused by surge or resonance It is determined to be sensed, generates a control signal for reducing the rotational force of the driving unit 120, and outputs the control signal to the driving unit 120. The driving unit 120 will reduce the rotational force according to the control signal.

A temperature sensor attached to the thrust bearing 154, such as a piezoelectric sensor 300, senses a temperature value of the thrust bearing 154 in real time, and outputs the detected temperature value to the controller 503.

The control unit 503 compares the temperature value of the thrust bearing 154 with a reference value, and as a result of the comparison, if the temperature value of the thrust bearing 154 exceeds the reference value, the thrust bearing 154 is diagnosed as having a failure. I will be able to do it.

8 is an exemplary view showing an output voltage value of the piezoelectric sensor 300 by pressure applied to the thrust bearing 154 according to an embodiment of the present invention.

As shown in FIG. 8, when pressure is applied to the foil bearing 154 according to the embodiment of the present invention, the inclined portion of the top foil 154a is deformed, and a piezoelectric sensor attached to the inclined portion due to the deformation of the inclined portion ( 300), the output voltage value increases. At this time, the control unit 503 compares the output voltage value of the piezoelectric sensor 300 with a reference value, and when the output voltage value of the piezoelectric sensor 300 exceeds the reference value, abnormal fluctuation of the turbocompressor caused by surge or resonance It is determined that this is detected, and by outputting a control signal for reducing the rotational force of the driving unit 120 to the driving unit 120, it is possible to prevent abnormal fluctuation of the turbocompressor caused by surge or resonance. .

9 is a flowchart illustrating a method of controlling a turbo compressor according to an embodiment of the present invention.

The turbo compressor performs normal operation (acceleration and constant speed operation) under the control of the control unit 503 (S11).

A plurality of piezoelectric sensors attached to the slope of the top foil 154a of the foil bearing 154 generate voltage values corresponding to the deformation of the slope of the top foil 154a, and control the voltage values in real time by the controller 503 Output to

The control unit 503 obtains an average value of voltage values output from a plurality of piezoelectric sensors attached to the inclined portion of the top foil 154a (S12). The control unit 503 may obtain an average value of temperature values output from a plurality of temperature sensors attached to the inclined portion of the top foil 154a.

The controller 503 compares the average value of voltage values output from the plurality of piezoelectric sensors attached to the slope of the top foil 154a with a reference voltage value (reference value), and as a result of the comparison, the average value of the voltage values is the reference voltage. It is determined whether the value (reference value) is exceeded (S13).

When the average value of the voltage values exceeds the reference voltage value (reference value), the control unit 503 determines that there is an abnormal fluctuation of the turbo compressor caused by surge or resonance, and the driving unit 120 determines that the abnormal fluctuation is stopped. It reduces the rotational force of the (rotational deceleration of the rotating shaft) (S14).

A temperature sensor attached to the thrust bearing 154, such as a piezoelectric sensor 300, senses a temperature value of the thrust bearing 154 in real time, and outputs the detected temperature value to the controller 503. The control unit 503 compares the temperature value of the thrust bearing 154 with a reference value, and as a result of the comparison, if the temperature value of the thrust bearing 154 exceeds the reference value, the thrust bearing 154 is diagnosed as having a failure. do.

As described above, in the turbocompressor according to the embodiment of the present invention, a piezoelectric element is applied to a thrust bearing in the turbocompressor, and abnormality of the turbocompressor due to surge or resonance is applied based on the voltage fluctuation of the piezoelectric element. Can detect movement.

The turbocompressor according to the embodiment of the present invention changes the operation of the turbocompressor when an abnormal movement (abnormal behavior) of the turbocompressor caused by surge or resonance in the turbocompressor is detected (e.g., turbocompressor Reducing the speed of), it is possible to secure the operation stability of the turbocompressor.

FIG. 10 is a conceptual diagram of a shaft motion sensor according to an embodiment of the present invention, FIG. 11 is a conceptual diagram showing a displacement sensing principle by the non-contact sensor shown in FIG. 7, and FIG. 12 is an enlarged view of B of FIG. 1. .

10 to 12, the turbo compressor may include a shaft motion sensor 200. The axis motion sensor 200 may include a non-contact sensor unit 201 and a marking unit 202.

The non-contact sensor unit 201 serves to detect the displacement of the rotation shaft 125, and the marking unit 202 may function as a target detected by the non-contact sensor unit 201.

The non-contact sensor unit 201 is formed to surround the rotation shaft 125 by being spaced apart from the outer circumferential surface of the rotation shaft 125. The non-contact sensor unit 201 may be formed in a cylindrical shape having a hollow. The non-contact sensor unit 201 is positioned to be fixed to the casing 110, and for this purpose, the casing 110 may include a fixing unit 203 extending toward the non-contact sensor unit 201. The non-contact sensor unit 201 may be configured to detect a change in distance from the surface of the rotating shaft 125 as a measurement object.

The marking unit 202 is formed on the outer circumferential surface of the rotation shaft 125 facing the non-contact sensor unit 201 and is configured to respond to a detection signal from the non-contact sensor unit 201. The non-contact sensor unit 201 may detect a change in the distance from the marking unit 202 among the surfaces of the rotation shaft 125 to obtain information on the displacement of the rotation shaft 125 including the marking unit 202.

Specifically, the axial motion sensor 200 of the present invention may detect the displacement of the rotating shaft 125 in a non-contact manner by an eddy current method. To this end, the marking unit 202 is made of a conductive metal, and the non-contact sensor unit 201 may be configured to generate an eddy current in the marking unit 202 and detect an impedance that changes according to the displacement of the marking unit 202. have.

Referring to FIG. 11, the principle of the eddy current sensor sensing displacement can be confirmed. The sensor coil 1 shown in FIG. 11 may be formed on the non-contact sensor unit 201 of the present invention, and the object 2 may be a rotation shaft 125 or a marking unit 202.

When a high-frequency current flows through the sensor coil 1, an alternating magnetic field M is formed in a space facing the object 2, which is a conductive material. In addition, an eddy current E is formed in the object 2 which is a conductive material by the alternating magnetic field M. At this time, when the object 2 approaches or moves away from the sensor coil 1, the inverse magnetic field R of the eddy current E is changed, and the impedance of the sensor coil 1 is changed by the inverse magnetic field R. . By measuring the impedance of the sensor coil 1, the positional relationship between the object 2 and the sensor coil 1 can be grasped.

Referring to FIG. 10, the axis motion sensor 200 includes a filter unit 204 that filters an impedance signal detected by the non-contact sensor unit 201, and an amplification unit 205 that amplifies the signal filtered by the filter unit 204. And, on the basis of the amplified signal information may further include a control unit 206 for calculating the displacement of the rotation shaft 125.

As described above, when the shaft motion sensor 200 of the present invention detects the displacement of the rotation shaft 125 by a non-contact method, abnormal behavior of the rotation shaft 125 including surge and resonance can be directly detected. . Compared to the conventional method of sensing the temperature, the flow rate or pressure of the refrigerant, the temperature of the components that are incidentally changed in the stage in which the abnormal behavior and the corresponding component damage proceeds, there is an advantage in that the reliability and precision of the measured value are high.

In addition, by applying the eddy current method, the non-contact sensor unit 201 of the present invention can detect a change in a relatively wide measurement surface at a fast response speed. In addition, there is an advantage that the rotation shaft 125 and the non-contact sensor unit 201 are not affected by a change of a medium material such as refrigerant or oil.

Meanwhile, the shaft behavior sensor 200 of the turbo compressor 100 according to the present invention may be configured to detect an abnormal behavior of the rotating shaft 125 by one signal channel. That is, the non-contact sensor unit 201 may include one sensor coil (not shown) that generates an eddy current. Hereinafter, a configuration configured to detect abnormal behavior of the rotation shaft 125 in various directions by one sensor coil (not shown) will be described.

In general, when considering material cost, the rotating shaft 125 may be made of a metallic material having electrical conductivity. Accordingly, the non-contact sensor unit 201 may detect a change in distance with the rotation shaft 125 by forming an eddy current on the surface of the rotation shaft 125. However, in this case, a plurality of sensor coils are provided so as to generate eddy currents at a plurality of points on the surface of the rotation shaft 125, and thus, the movement direction of the rotation shaft 125 must be recognized.

Unlike this configuration, the present invention has a structure in which the marking portion 202 is separately formed on the rotation shaft 125. In this case, the marking part 202 may be made of a material having a greater electrical conductivity than the rotation shaft 125 so as to react more sensitively to the detection signal of the non-contact sensor part 201 than the surface of the rotation shaft 125. For example, the marking part 202 may be formed of a nickel material. In addition, when the marking part 202 is made of a material different from the rotation shaft 125 and is located at the end of the rotation shaft 125, it may cause resonance with the impellers 131 and 141. Accordingly, the marking portion 202 is formed in a manner that is coated on the surface of the rotation shaft 125 to minimize disturbance.

As shown in FIG. 12, the marking unit 202 includes a plurality of first marks 202a, a plurality of second marks 202b, and a plurality of third marks 203b spaced apart from each other in the axial direction of the rotation shaft 125. ) Can be included. The separation distance between the plurality of marks 202a, 202b, and 202c may be formed to have a value equal to or greater than a preset distance d. The first to three marks 202a, 202b, and 202c may be disposed to be spaced apart from each other along the axial direction. The second mark 202b and the third mark 202c may be disposed to face each other around the first mark 202a.

Each of the first marks 202a may be inclined at a predetermined angle θ with respect to the axial direction of the rotation shaft 125 and may extend parallel to each other.

The second mark 202b may be disposed in a longitudinal direction perpendicular to the axial direction.

The third mark 202c may be arranged in a longitudinal direction parallel to the axial direction.

The non-contact sensor unit 201 includes a first sensor 201a facing the first mark 202a in a direction perpendicular to the axial direction, and a second sensor facing the second mark 202b in a direction perpendicular to the axial direction. It may include (201b) and a third sensor (201c) facing the third mark (202c) in a direction perpendicular to the axial direction.

The rotating shaft 125 on which the marking part 202 is formed is rotated at high speed when the turbo compressor 100 of the present invention is operated. The sensor coil provided at one point of the non-contact sensor unit 201 fixed to the casing 110 can detect a change in impedance when the marking unit 202 is moved in the circumferential direction or axial direction of the rotation shaft 125. In addition, the control unit 206 may determine such a change as a normal driving state.

However, when the rotation shaft 125 is moved in the axial direction or radial direction of the rotation shaft 125 by more than a specific displacement, the impedance change detected by the sensor coil accordingly may be determined as an abnormal behavior state by the controller 206. . When the plurality of first marks 202a are inclined at an angle of approximately 45 degrees with respect to the axial direction of the rotation shaft 125, the displacement of the marks 202a in the axial and radial directions of the rotation shaft 125 is caused by the sensor coil. Can be detected.

And, based on the information sensed from the first sensor 201a, when detecting the abnormal behavior of the rotating shaft 125, the control unit 206, the impedance change value sensed from the second sensor 201b, and the third sensor 201c By comparing the impedance change value sensed from ), it is possible to detect whether the rotation shaft 125 has an abnormal behavior in the axial direction or an abnormal behavior in the radial direction.

The first to three sensors 201a, 201b, and 201c may be sufficiently separated so as not to be affected by the impedance change value of other marks.

Further, the non-contact sensor unit 201 may be formed to be longer than the length of the marking unit 202 in the axial direction of the rotation shaft 125 to overlap the marking unit 202.

The non-contact sensor unit 201 includes a plurality of sensor coils, and the marking unit 202 includes a plurality of marks 202a, 202b, and 202c arranged at a predetermined distance (d) and angle (θ). It is efficient because it can detect various displacements of 125 through one signal channel.

In the above, a configuration capable of quickly detecting the displacement of rotating components including the rotating shaft 125 has been described. Hereinafter, characteristics of the control unit 206 that can immediately use the detected and calculated displacement will be described.

13 is a flowchart illustrating a method of controlling the turbo compressor of the present invention by the control unit shown in FIG. 10. As described above, the control unit 206 may calculate the displacement of the rotation shaft 125 based on signal information transmitted from the sensor coil of the non-contact sensor unit 201. In addition, the control unit 206 is configured to change the rotation speed of the turbo compressor of the present invention based on the calculated displacement of the rotation shaft 125. In particular, such a control process may be performed to change the rotation speed of the rotation shaft 125 by receiving a signal from the non-contact sensor unit 201 in real time.

As shown in FIG. 13, the control unit 206 detects the displacement of the rotation shaft 125 by detecting the first mark 202a of the first sensor 201a while the turbocompressor of the present invention is operating normally. Can be converted. In this case, the normal operation state may be a state in which the compressor is operated at a constant speed, or a state in which the operating speed is increased to respond to an increase in load.

When the displacement of the rotation shaft 125 is calculated, the controller 206 may compare the current displacement value of the rotation shaft 125 with a preset value.

Here, the preset value may be a maximum displacement that can be determined that the displacement of the rotation shaft 125 is within the normal operation range.

When the displacement of the rotating shaft 125 is within a preset value, the control unit 206 may maintain the operating condition of the compressor as it is.

However, when the displacement of the rotation shaft 125 is out of a preset range, the controller 206 may determine that the turbo compressor of the present invention exhibits abnormal behavior.

Therefore, the impedance change amount (first change amount) according to the detection of the second mark 202b of the second sensor 201b and the impedance change amount (second change amount) according to the detection of the third mark 202c of the third sensor 201c In comparison, when the first change amount is greater than the second change amount, the control unit 206 may determine that the rotation shaft 125 is abnormally moved in the axial direction. Next, when the second change amount is greater than the first change amount, the controller 206 may determine that the rotation shaft 125 is abnormally moved in the radial direction.

When the turbo compressor of the present invention is operated, the detection and response of the driving state described with reference to FIG. 10 may be continuously performed at preset time intervals. This control scheme enables rapid detection of the abnormal behavior of the compressor, and also makes it possible to proactively react before the compressor completely malfunctions or is damaged. Therefore, in the case of grasping the abnormal behavior by the conventional temperature or flow distribution, it is possible to prevent or minimize damage, unlike the possibility that structural damage has already progressed when the abnormal behavior is detected.

In the above, even if all the constituent elements constituting the embodiments of the present invention have been described as being combined into one or operating in combination, the present invention is not necessarily limited to these embodiments. That is, within the scope of the object of the present invention, all the constituent elements may be selectively combined and operated in one or more. In addition, terms such as'include','comprise', or'have' described above mean that the corresponding component can be present unless otherwise stated, so other components are excluded. It should not be construed as being able to further include other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art, unless otherwise defined. Terms generally used, such as terms defined in the dictionary, should be interpreted as being consistent with the meaning of the context of the related technology, and are not interpreted as ideal or excessively formal meanings unless explicitly defined in the present invention.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (5)

Casing;
A driving unit provided in the inner space of the casing to generate a rotational force;
A rotation shaft installed to pass through the casing and transmitting a rotational force generated by the driving unit;
A shaft motion sensor formed to sense the displacement of the rotation shaft;
A compression unit that rotates with the rotation shaft and includes an impeller for compressing the sucked fluid;
An axial support plate coupled to the rotation shaft and positioned adjacent to the driving unit;
A thrust bearing installed on the casing to support the axial support plate;
A sensor module attached to one side of the thrust bearing and including a piezoelectric sensor for generating a voltage by deformation according to pressure applied to the thrust bearing, and a temperature sensor for sensing a temperature of the thrust bearing; And
Comprising a control unit that compares the voltage value generated by the piezoelectric sensor with a set reference value, determines that it is oscillation when it is equal to or greater than a certain value, and controls the rotational force of the driving unit,
The compression unit is provided in plural, and includes a first compression unit and a second compression unit which are arranged in succession along the axial direction,
The first compression unit includes a first impeller housing and a first impeller disposed in the first impeller housing,
The second compression unit includes a second impeller housing and a second impeller disposed in the second impeller housing,
At one end of the first impeller housing, a suction pipe is connected and a first inlet through which refrigerant is sucked is disposed,
Between the first impeller housing and the second impeller housing, a second inlet for transferring the refrigerant in the first impeller housing to the second impeller housing is disposed,
The diameter of the second inlet (D2) is formed smaller than the diameter of the first inlet (D1),
It includes a back pressure space disposed on the rear side of the second impeller among the spaces in the casing,
And a back pressure flow path connected between the outlet of the second impeller housing and the back pressure space,
And a back pressure control valve installed between the back pressure passage and the back pressure space to selectively open and close between the back pressure passage and the back pressure space,
The back pressure flow path includes a first back pressure flow path disposed in the housing forming a wall of the second impeller housing, and a second back pressure flow path disposed in the front frame of the casing and communicating with the first back pressure flow path,
A valve space having a predetermined depth in the radial direction is formed in the front frame, and the back pressure control valve is disposed in the valve space,
A first back pressure hole is formed between the valve space and the back pressure space,
The first back pressure hole is disposed in the radial center of the valve space,
And a second back pressure hole communicating the valve space and the inner space of the casing,
The second back pressure hole is disposed inside the first back pressure hole with respect to the radial direction of the rotation shaft,
The second back pressure flow path is disposed outside the first back pressure hole with respect to the radial direction of the rotation shaft,
The back pressure control valve includes a valve spring having one end disposed on an inner surface of the valve space, and a back pressure valve disposed at the other end of the valve spring and moving in the first back pressure hole and in a radial direction,
The first back pressure hole has a shape in which a cross-sectional area is increased in a direction from the compression unit toward the drive unit,
An inclined surface is disposed on the inner circumferential surface of the first back pressure hole,
The inclined surface of the first back pressure hole has a shape in which the cross-sectional area of the first back pressure hole increases from the compression unit to the drive unit,
The thrust bearing is made of a foil bearing,
The foil bearing may include a bump block fixedly installed on one surface along a radial direction at regular intervals;
A top foil having one end attached to the bump block and formed to have a constant inclination in a direction in close contact with the axial support plate from one end to the other; And
It is located under the top foil and includes a bump foil made to have an elastic force,
The piezoelectric sensor,
It is fixedly installed on the inclined rear portion of the top foil, and is located between the bump block and the top foil,
The top foil,
A fixing part fixed to the bump block;
An inclined portion extending from the fixed portion and having a constant inclination;
It includes a flat portion extending from the inclined portion and extending to have a regular interval with the axial support plate,
The inclined portion is deformed by the pressure applied to the foil bearing,
The piezoelectric sensor generates a voltage value by the deformation,
The temperature sensor measures a current temperature value of the thrust bearing in real time, outputs the measured current temperature value to the control unit,
The bump block is disposed to overlap the fixing part and the inclined part in a vertical direction,
The piezoelectric sensor and the temperature sensor are disposed between the bump block and the fixing part, and between the bump block and the inclined part,
The upper surface of the bump block supports the lower surface of the piezoelectric sensor and the temperature sensor, and the lower surface is supported by the upper surface of the bump foil,
The axis motion sensor,
A non-contact sensor unit positioned to be fixed to the casing and formed to surround the outer circumferential surface of the rotation shaft to be spaced apart, and detect a change in distance with the rotation shaft; And
And a marking part formed on an outer circumferential surface of the rotation shaft facing the non-contact sensor part and made to respond to a detection signal of the non-contact sensor part,
The marking unit includes a plurality of first marks, a plurality of second marks, and a plurality of third marks spaced apart in the axial direction of the rotation shaft,
The first to third marks are spaced a predetermined distance,
The second mark and the third mark are arranged to face each other around the first mark,
The first mark is disposed to be inclined 45 degrees with respect to the axial direction of the rotation shaft,
The second mark is arranged in a longitudinal direction perpendicular to the axial direction of the rotation shaft,
The third mark is arranged in a longitudinal direction parallel to the axial direction of the rotation axis,
The non-contact sensor unit,
A first sensor facing the first mark in a direction perpendicular to an axial direction;
A second sensor facing the second mark in a direction perpendicular to an axial direction; And
And a third sensor facing the third mark in a direction perpendicular to the axial direction,
The control unit detects the displacement of the rotation shaft by detecting the first mark by the first sensor, and when the displacement of the rotation shaft exceeds a preset range, the impedance change amount of the second sensor and the impedance change amount of the third sensor are determined. Compare,
When the impedance change amount sensed by the second sensor is greater than the impedance change amount sensed by the third sensor, the control unit determines that the rotation shaft is abnormally behaving in the axial direction,
When the impedance change amount sensed by the third sensor is greater than the impedance change amount sensed by the second sensor, the control unit determines that the rotation shaft abnormally moves in a radial direction.
The method of claim 1,
The marking part is a turbo compressor formed of a conductive metal.
The method of claim 1,
The non-contact sensor unit turbo compressor having one sensor coil generating an eddy current.
The method of claim 1,
The control unit is a turbo compressor that controls to change the rotation speed of the rotation shaft.
The method of claim 1,
When the temperature value of the thrust bearing exceeds a set value, the control unit determines the abnormal behavior of the compressor.

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