JP6079486B2 - Liquid level measuring device, turbo compressor and turbo refrigerator - Google Patents

Description

  The present invention relates to a liquid level measuring device, a turbo compressor, and a turbo refrigerator.

  As a refrigerator, a turbo refrigerator having a turbo compressor that compresses and discharges a refrigerant by rotating an impeller with an electric motor is known. In a turbo compressor, lubricating oil is supplied from an oil tank to sliding parts such as a bearing of a rotating shaft of an electric motor and a bearing of a rotating shaft of an impeller. As described above, oil leakage from the seal portion that seals the periphery of the rotating shaft to another space is a problem at the site where the lubricating oil is supplied.

  Conventionally, in order to confirm the occurrence of this oil leak, a liquid level measurement display device for measuring the liquid level of the oil tank is provided. Patent Document 1 describes an oil level gauge attached to an oil tank as a liquid level measuring device. This oil level gauge communicates with the bottom and top of the oil tank and takes the liquid into the straight pipe to measure the liquid level.

Japanese Patent Laid-Open No. 10-220885

  By the way, in the turbo compressor, when the oil tank is arranged below the gear unit, the oil falls from the gear unit, and the liquid level is ramped in a short period. It may become. In addition, when the turbo compressor is started, the oil tank foams, so that the range may be over and it may be difficult to measure the liquid level.

  For this reason, conventionally, a vertically long large oil level gauge as shown in Patent Document 1 has been installed in an oil tank of a turbo compressor. However, there is a problem that the large oil level gauge is expensive.

  The present invention has been made in view of the above problems, and aims to provide a liquid level measuring device, a turbo compressor, and a turbo refrigerator that are inexpensive, have a large measurement range, and can accurately measure the liquid level. To do.

In order to solve the above-described problems, the present invention provides a first sight glass that measures a liquid level from a first direction, and a measurement that overlaps a part of the measurement region of the first sight glass in the height direction. A liquid level measuring device having a region and a second sight glass that measures the liquid level from a second direction different from the first direction is employed.
By adopting this configuration, the liquid level is measured using the first sight glass and the second sight glass in the present invention. By using the first sight glass and the second sight glass, a small and inexpensive one can be selected as compared with the case where the liquid level is measured with only one sight glass. In the present invention, the first sight glass and the second sight glass are arranged in a three-dimensional arrangement by changing the directions of the first sight glass and the second sight glass. It can be placed and held, and a large measurement range can be secured.

Moreover, in this invention, it has a horizontal hole part which guide | induces a liquid to a horizontal direction, and the said 1st sight glass and the said 2nd sight glass employ | adopt the structure of measuring a liquid level in the said horizontal hole part.
By adopting this configuration, in the present invention, the liquid level is measured by the first sight glass and the second sight glass after the liquid is led out in the horizontal direction by the side hole portion. By providing the horizontal hole portion, for example, even when the liquid is pouring onto the liquid surface, the liquid level can be accurately measured at a location where the liquid surface is stable away from the liquid drop point.

Moreover, in this invention, the said 1st sight glass is provided in the back end of the said side hole part, and the said 2nd sight glass is a near side rather than the said 1st sight glass in the said side hole part. And the structure of being provided in the side wall of the said horizontal hole part is employ | adopted.
By adopting this configuration, in the present invention, the first sight glass is provided at the far end of the horizontal hole where the liquid level is most stable. Further, in the present invention, the second sight glass is provided on the side wall of the lateral hole portion that is substantially parallel in a plan view with respect to the intrusion direction of the liquid that pours and is relatively less liable to fall. Thereby, even if it is a case where the liquid has poured on the liquid level, a liquid level can be measured correctly.

Moreover, in this invention, the structure that the said 2nd sight glass is provided in the position relatively higher than the said 1st sight glass is employ | adopted.
By adopting this configuration, in the present invention, since the liquid that pours into obliquely enters the side hole portion, the second sight glass is made relatively higher than the first sight glass, so that the front side The liquid is prevented from falling on the second sight glass provided in. Thereby, even if it is a case where the liquid has poured on the liquid level, a liquid level can be measured correctly.

In the present invention, a configuration is adopted in which the second sight glass is relatively smaller than the first sight glass.
By adopting this configuration, in the present invention, since the installation area is reduced by making the second sight glass relatively smaller than the first sight glass, the second site provided on the near side. The liquid will not fall on the glass. Thereby, even if it is a case where the liquid has poured on the liquid level, a liquid level can be measured correctly.

Moreover, in this invention, the structure that the said 1st direction and said 2nd direction are mutually orthogonal directions in a horizontal surface is employ | adopted.
By adopting this configuration, in the present invention, the liquid level can be accurately measured from two directions orthogonal to each other on the horizontal plane.

  Further, in the present invention, a turbo compressor that compresses gas by rotating an impeller by an electric motor, the gear unit transmitting rotational driving force of the electric motor to the impeller, and the gear below the gear unit. An oil tank that stores lubricating oil supplied to the unit is used, and the liquid level measuring device described above is used as the liquid level measuring device that measures the liquid level of the oil tank.

  In the present invention, the condenser that liquefies the compressed refrigerant, the evaporator that evaporates the liquefied refrigerant by the condenser and cools the object to be cooled, and the refrigerant evaporated by the evaporator A turbo refrigerator having a turbo compressor that compresses and supplies the turbo compressor to the condenser, and has the turbo compressor described above as the turbo compressor.

  According to the present invention, it is possible to obtain a liquid level measuring device, a turbo compressor, and a turbo refrigerator that are inexpensive, have a large measurement range, and can accurately measure the liquid level.

It is a systematic diagram of the turbo refrigerator in the embodiment of the present invention. It is a perspective view of the liquid level measuring device provided in the oil tank cover in the embodiment of the present invention. It is a rear view of the oil tank cover in the embodiment of the present invention. It is a figure for demonstrating the positional relationship of the height direction of the 1st sight glass and 2nd sight glass in embodiment of this invention. It is a figure for demonstrating the effect | action of the liquid level measuring apparatus in embodiment of this invention. It is a perspective view of the liquid level measuring device provided in the oil tank cover in another embodiment of the present invention. It is a perspective view of the liquid level measuring device provided in the oil tank cover in another embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a system diagram of a turbo refrigerator 1 in an embodiment of the present invention.
The turbo refrigerator 1 of the present embodiment uses, for example, chlorofluorocarbon as a refrigerant and air-conditioning cold water as a cooling object. As shown in FIG. 1, the turbo refrigerator 1 includes a condenser 2, an economizer 3, an evaporator 4, and a turbo compressor 5.

  The condenser 2 is connected to the gas discharge pipe 5a of the turbo compressor 5 via the flow path R1. Refrigerant (compressed refrigerant gas X1) compressed by the turbo compressor 5 is supplied to the condenser 2 through the flow path R1. The condenser 2 liquefies the compressed refrigerant gas X1. The condenser 2 includes a heat transfer pipe 2a through which cooling water flows, and cools the compressed refrigerant gas X1 by heat exchange between the compressed refrigerant gas X1 and the cooling water.

  The compressed refrigerant gas X1 is cooled by heat exchange with the cooling water, liquefied, becomes refrigerant liquid X2, and accumulates at the bottom of the condenser 2. The bottom of the condenser 2 is connected to the economizer 3 via the flow path R2. An expansion valve 6 for reducing the pressure of the refrigerant liquid X2 is provided in the flow path R2. The economizer 3 is supplied with the refrigerant liquid X2 decompressed by the expansion valve 6 through the flow path R2. The economizer 3 temporarily stores the decompressed refrigerant liquid X2, and separates the refrigerant into a liquid phase and a gas phase.

  The top of the economizer 3 is connected to the economizer connecting pipe 5b of the turbo compressor 5 through the flow path R3. The gas phase component X3 of the refrigerant separated by the economizer 3 is supplied to the turbo compressor 5 through the flow path R3 to the second compression stage 12 without passing through the evaporator 4 and the first compression stage 11, and the efficiency Is to increase. On the other hand, the bottom of the economizer 3 is connected to the evaporator 4 via a flow path R4. The flow path R4 is provided with an expansion valve 7 for further reducing the pressure of the refrigerant liquid X2.

  The evaporator 4 is supplied with the refrigerant liquid X2 further reduced in pressure by the expansion valve 7 through the flow path R4. The evaporator 4 evaporates the refrigerant liquid X2 and cools the cold water by the heat of vaporization. The evaporator 4 includes a heat transfer tube 4a through which cold water flows, and cools the cold water and evaporates the refrigerant liquid X2 by heat exchange between the refrigerant liquid X2 and the cold water. Refrigerant liquid X2 takes heat by heat exchange with cold water and evaporates to become refrigerant gas X4.

  The top of the evaporator 4 is connected to a gas suction pipe 5c of the turbo compressor 5 via a flow path R5. The refrigerant gas X4 evaporated in the evaporator 4 is supplied to the turbo compressor 5 through the flow path R5. The turbo compressor 5 compresses the evaporated refrigerant gas X4 and supplies it to the condenser 2 as the compressed refrigerant gas X1. The turbo compressor 5 is a two-stage compressor including a first compression stage 11 that compresses the refrigerant gas X4 (gas) and a second compression stage 12 that further compresses the one-stage compressed refrigerant.

  The first compression stage 11 is provided with an impeller 13, and the second compression stage 12 is provided with an impeller 14, which are connected by a rotating shaft 15. The turbo compressor 5 rotates the impellers 13 and 14 by the electric motor 10 to compress the refrigerant. The impellers 13 and 14 are radial impellers, and have blades including a three-dimensional twist (not shown) that guides the refrigerant sucked in the axial direction in the radial direction.

  An inlet guide vane 16 for adjusting the suction amount of the first compression stage 11 is provided in the gas suction pipe 5c. The inlet guide vane 16 is rotatable so that the apparent area from the flow direction of the refrigerant gas X4 can be changed. Diffuser flow paths are provided around the impellers 13 and 14, respectively, and the refrigerant derived in the radial direction is compressed and pressurized in the flow paths, and further is scrolled by a scroll flow path provided therearound. Can be supplied to the compression stage. An outlet throttle valve 17 is provided around the impeller 14 so that the discharge amount from the gas discharge pipe 5a can be controlled.

  The turbo compressor 5 includes a sealed casing 20. The housing 20 is partitioned into a compression flow path space S1, a first bearing housing space S2, a motor housing space S3, a gear unit housing space S4, and a second bearing housing space S5. Impellers 13 and 14 are provided in the compression flow path space S1. The rotating shaft 15 that connects the impellers 13 and 14 is provided so as to be inserted into the compression flow path space S1, the first bearing housing space S2, and the gear unit housing space S4. A bearing 21 that supports the rotary shaft 15 is provided in the first bearing housing space S2.

  In the motor housing space S3, a stator 22, a rotor 23, and a rotating shaft 24 connected to the rotor 23 are provided. The rotating shaft 24 is provided so as to be inserted into the motor housing space S3, the gear unit housing space S4, and the second bearing housing space S5. In the second bearing housing space S5, a bearing 31 that supports the non-load side of the rotating shaft 24 is provided. A gear unit 25, bearings 26 and 27, and an oil tank 28 are provided in the gear unit housing space S4.

  The gear unit 25 includes a large-diameter gear 29 that is fixed to the rotary shaft 24, and a small-diameter gear 30 that is fixed to the rotary shaft 15 and meshes with the large-diameter gear 29. The gear unit 25 transmits the rotational driving force so that the rotational speed of the rotary shaft 15 increases (increases) with respect to the rotational speed of the rotary shaft 24. The bearing 26 supports the rotating shaft 24. The bearing 27 supports the rotating shaft 15. The oil tank 28 is provided below the gear unit 25 and stores lubricating oil supplied to each sliding portion such as the bearings 21, 26, 27, and 31. The oil tank 28 is provided with an oil supply pump 37 that supplies lubricating oil to each sliding portion.

  Such a casing 20 is provided with seal portions 32 and 33 for sealing the periphery of the rotary shaft 15 between the compression flow path space S1 and the first bearing housing space S2. Further, the casing 20 is provided with a seal portion 34 that seals the periphery of the rotary shaft 15 between the compression flow path space S1 and the gear unit accommodation space S4. The casing 20 is provided with a seal portion 35 that seals the periphery of the rotary shaft 24 between the gear unit accommodation space S4 and the motor accommodation space S3. Further, the casing 20 is provided with a seal portion 36 that seals the periphery of the rotary shaft 24 between the motor housing space S3 and the second bearing housing space S5.

  By the way, in the gear unit housing space S4, the lubricating oil is scooped up by the large-diameter gear 29 that transmits the rotational driving force to the impellers 13 and 14 of the gear unit 25, and mist-like oil droplets and smoke are generated. . Further, since the seals at the sliding portions of the rotary shafts 15 and 24 are not perfect, when the lubricating oil leaks into another space due to a space pressure difference or the like, the so-called oil rise in which the liquid level of the oil tank 28 is lowered. May occur. For this reason, the oil tank 28 is provided with a liquid level measuring device 40 for monitoring the rise of oil.

Hereinafter, the configuration of the liquid level measuring device 40 will be described with reference to FIGS.
FIG. 2 is a perspective view of the liquid level measuring device 40 provided in the oil tank cover 50 in the embodiment of the present invention. FIG. 3 is a rear view of the oil tank cover 50 according to the embodiment of the present invention. FIG. 4 is a diagram for explaining the positional relationship in the height direction between the first sight glass 41 and the second sight glass 42 in the embodiment of the present invention. FIG. 5 is a diagram for explaining the operation of the liquid level measuring device 40 according to the embodiment of the present invention. In the following description, an XYZ orthogonal coordinate system may be set, and the positional relationship of each member may be described with reference to this XYZ orthogonal coordinate system.

  The liquid level measuring device 40 of the present embodiment is provided on the oil tank cover 50 as shown in FIG. The oil tank cover 50 has a mounting flange 50a through which a bolt is inserted. The attachment flange 50a is attached to the side wall 28a of the oil tank 28 as shown in FIG. The side wall 28a of the oil tank 28 is formed with a through hole 28a1 that penetrates horizontally in the thickness direction (X-axis direction). The oil tank cover 50 is bolted to the side wall 28a via the mounting flange 50a to close the through hole 28a1.

  The oil tank cover 50 holds an oil supply pump 37 as shown in FIG. The oil supply pump 37 is configured to take in the lubricating oil from the oil tank 28 and supply the lubricating oil to each sliding portion such as the bearings 21, 26, 27, and 31 through a pipe (not shown). The oil tank cover 50 holds an oil strainer 38. The oil strainer 38 removes foreign matters contained in the lubricating oil to be supplied. The oil strainer 38 has a mesh structure and is formed in a column shape.

  As shown in FIG. 2, the oil tank cover 50 has a convex portion 51 that protrudes outward (−X side) so as to accommodate the oil strainer 38. The liquid level measuring device 40 of the present embodiment is provided on the convex portion 51. The liquid level measuring device 40 includes a first sight glass 41 and a second sight glass 42. The first sight glass 41 is a circular transparent member, and a mounting flange 41a is integrally provided around it. The second sight glass 42 is a circular transparent member having the same size as the first sight glass 41, and a mounting flange 42a is integrally provided around the second sight glass 42.

  The 1st sight glass 41 and the 2nd sight glass 42 are provided in the horizontal hole part 43, as shown in FIG. The lateral hole portion 43 is formed next to the oil strainer 38 in the oil tank cover 50 and has a depth equivalent to that of the oil strainer 38. That is, the lateral hole portion 43 is formed using a protruding shape toward the outside (−X side) by the oil strainer 38. As shown in FIG. 5, the lateral hole portion 43 communicates with the through hole 28 a 1 of the oil tank 28, and guides the lubricating oil from the oil tank 28 in the horizontal direction (−X side).

  The first sight glass 41 and the second sight glass 42 are configured to measure the liquid level in the side hole portion 43. As shown in FIG. 5, the first sight glass 41 is provided at the back end 44 of the horizontal hole portion 43, and is configured to measure the liquid level from the first direction (X-axis direction). A through hole 44a1 that penetrates horizontally in the thickness direction (X-axis direction) is formed in the back end 44. The first sight glass 41 is bolted through the mounting flange 41a and closes the through hole 44a1.

  On the other hand, as shown in FIG. 5, the second sight glass 42 is provided on the side wall 45 of the lateral hole portion 43 on the near side of the first sight glass 41 in the lateral hole portion 43. The liquid level is measured from the direction (Y-axis direction). The side wall 45 is formed with a through hole 45a1 penetrating horizontally in the thickness direction (Y-axis direction). The second sight glass 42 is bolted via a mounting flange 42a and closes the through hole 45a1.

  When viewed from the outside as shown in FIG. 2, the first sight glass 41 is provided on the tip surface 51 a of the convex portion 51. The second sight glass 42 is provided on the side wall surface 51 b orthogonal to the tip surface 51 a of the convex portion 51. In addition, the seat 52 which improves the sitting of the 2nd sight glass 42 is provided in the side wall surface 51b. As described above, the first direction in which the liquid level is measured from the first sight glass 41 and the second direction in which the liquid level is measured from the second sight glass 42 are orthogonal to each other in the horizontal plane (XY plane). It has become a direction.

  The second sight glass 42 is provided at a position relatively higher than the first sight glass 41. If the 1st sight glass 41 and the 2nd sight glass 42 which were provided in the different plane in the convex part 51 are represented on the same plane as shown in FIG. 4, it has the following positional relationships. That is, the measurement region L1 of the first sight glass 41 and the measurement region L2 of the second sight glass 42 partially overlap in the height direction. Thus, the 1st sight glass 41 and the 2nd sight glass 42 are arranged with continuity in the height direction.

  Next, the operation of the liquid level measuring device 40 having the above configuration will be described.

  As shown in FIG. 1, when the turbo compressor 5 is driven, the refrigerant gas X4 of the evaporator 4 is sucked by the impellers 13 and 14 and compressed to be compressed refrigerant gas X1 and led to the condenser 2. And this refrigerant | coolant circulates through the condenser 2, the evaporator 4, and the turbo compressor 5 in order, and a refrigerating cycle is repeated. The turbo compressor 5 has a gear unit 25 for transmitting the rotational driving force of the electric motor 10 to the impellers 13 and 14. Below the gear unit 25, an oil tank 28 for storing lubricating oil supplied to the gear unit 25 is provided.

  Since the gear unit 25 generates heat at a high temperature, a large amount of lubricating oil is supplied, and the lubricating oil is poured into the oil tank 28 from above. For this reason, as shown in FIG. 5, the liquid level 100 in the oil tank 28 is violently ramped in a short period. The oil tank 28 is provided with a liquid level measuring device 40 for confirming at which timing oil leakage has occurred when the turbo compressor 5 is driven. As shown in FIG. 2, the liquid level measuring device 40 uses a first sight glass 41 and a second sight glass 42 to measure the liquid level.

  According to the liquid level measuring device 40, by using these two sight glasses, the sight glass per one can be made small and inexpensive. If the same measurement range is to be secured with only one sight glass, the size (area) of the sight glass needs to be about four times larger, which is more expensive than preparing two small sight glasses. Become. On the other hand, since there is a mounting flange 41a around the first sight glass 41 and there is a mounting flange 42a around the second sight glass 42, the height direction is simply arranged in a line vertically. The continuity cannot be given.

  Therefore, in the present embodiment, as shown in FIG. 2, the orientation of the first sight glass 41 and the second sight glass 42 is changed to provide a three-dimensional arrangement. Thereby, the 1st sight glass 41 and the 2nd sight glass 42 can be set as the arrangement | positioning which gave continuity so that some measurement area | regions L1 and L2 may overlap in a height direction (refer FIG. 4). ) Even a small and inexpensive sight glass can secure a large measurement range. Therefore, according to the liquid level measuring device 40, the liquid level can be accurately measured without over-range even in the oil tank 28 having a large change in the liquid level.

  Further, according to the liquid level measuring device 40, as shown in FIG. 5, the liquid level is adjusted by the first sight glass 41 and the second sight glass 42 after the liquid is guided in the horizontal direction by the side hole 43. It comes to measure. When the lubricating oil is poured on the liquid level 100 in the oil tank 28, the liquid level measurement point can be set at a position away from the falling point of the lubricating oil by providing the lateral hole portion 43. For this reason, in the horizontal hole portion 43, the liquid level can be measured while the liquid level 100 is more stable than the oil tank 28.

  Further, since the liquid level 100 becomes more stable as the distance from the drop point of the lubricating oil increases, the first sight glass 41 is provided at the back end 44 of the lateral hole portion 43, so that the liquid level 100 is in a most stable state, The surface depth can be well monitored. Further, the second sight glass 42 is provided on the side wall 45 of the lateral hole portion 43, and the side wall 45 stands substantially parallel to the intrusion direction (X-axis direction) of the lubricating oil that pours down in a plan view. Lubricating oil is less likely to fall.

  Further, as shown in FIG. 5, since the liquid that pours into the side hole portion 43 obliquely enters, the second sight glass 42 is made relatively higher than the first sight glass 41, so that the front side Thus, it is possible to prevent the liquid from dripping so much with respect to the second sight glass 42 provided in. Therefore, as shown in FIG. 5, even when the lubricating oil is poured on the liquid level 100, the liquid level can be measured accurately. Thus, according to the liquid level measuring device 40, the liquid level can be accurately measured from two directions orthogonal to each other on the horizontal plane.

  Thus, according to the above-described embodiment, the first sight glass 41 that measures the liquid level from the first direction and a part of the measurement region L1 of the first sight glass 41 in the height direction overlap. By using the liquid level measuring device 40 having the measurement region L2 to be measured and the second sight glass 42 that measures the liquid level from a second direction different from the first direction, it is possible to measure at a low price with a large amount. A range can be provided, and the liquid level can be accurately measured even when the lubricating oil is poured on the liquid level 100 in the oil tank 28.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, the present invention can adopt the forms shown in FIGS. 6 and 7 below. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

FIG. 6 is a perspective view of a liquid level measuring device 40A provided in the oil tank cover 50 according to another embodiment of the present invention.
As shown in FIG. 6, the second sight glass 42 of the liquid level measuring device 40 </ b> A is relatively smaller than the first sight glass 41. According to this configuration, since the installation area (occupied area) of the second sight glass 42 can be suppressed to be small, the area on which the lubricating oil falls on the second sight glass 42 is also reduced. Therefore, the lubricating oil does not fall on the second sight glass 42 provided on the front side in the side hole portion 43, and the liquid level can be measured more accurately.

FIG. 7 is a perspective view of a liquid level measuring device 40B provided in the oil tank cover 50 according to another embodiment of the present invention.
As shown in FIG. 7, two second sight glasses 42 of the liquid level measuring device 40B are provided. Moreover, the 1st sight glass 41 and the 2nd sight glass 42 are staggered arrangement | positioning. According to this configuration, the first sight glass 41 and the second sight glass 42 can be arranged to have continuity in the height direction, and a larger measurement range can be secured. Further, the liquid level measuring device 40B is provided with a scale 53 in which a scale is formed so as to straddle the tip surface 51a and the side wall surface 51b of the convex portion 51. According to this configuration, one scale 53 can cover a large measurement range, and can contribute to cost reduction.

  For example, in the said embodiment, although the form which each installs the 1st sight glass 41 and the 2nd sight glass 42 or 2 each was illustrated, this invention is not limited to this form, FIG. If it arrange | positions in zigzag form as shown in 7, the 1st sight glass 41 and the 2nd sight glass 42 can each be installed, for example.

  For example, in the above embodiment, the liquid level measuring device 40 is applied to the oil tank 28 of the turbo compressor 5. However, the present invention is not limited to this form, and other liquid reservoirs are used. Is also applicable. For example, the present invention can be applied to a liquefied gas tank, and can be more suitably applied to a liquid circulation system tank in which liquid circulates and the total amount of liquid does not change much.

  DESCRIPTION OF SYMBOLS 1 ... Turbo refrigerator, 2 ... Condenser, 4 ... Evaporator, 5 ... Turbo compressor, 10 ... Electric motor, 13 ... Impeller, 14 ... Impeller, 25 ... Gear unit, 28 ... Oil tank, 40 ... Liquid level measuring device 41 ... first sight glass, 42 ... second sight glass, 43 ... horizontal hole, 44 ... back end, 45 ... side wall, L1 ... measurement region, L2 ... measurement region, X4 ... refrigerant gas (gas)

Claims (6)

A first sight glass for measuring the liquid level from the first direction;
A second sight glass that has a measurement region that overlaps a part of the measurement region of the first sight glass in the height direction and that measures the liquid level from a second direction different from the first direction; Yes, and
It has a side hole that guides the liquid horizontally,
The first sight glass is provided at the back end of the side hole,
The liquid level measuring device according to claim 2, wherein the second sight glass is provided in front of the first sight glass in the side hole portion and on a side wall of the side hole portion . The liquid level measuring device according to claim 1 , wherein the second sight glass is provided at a relatively higher position than the first sight glass. It said second sight glass is relatively the first sight glass smaller than that liquid level measuring device according to claim 1 or 2, characterized in. The liquid level measuring device according to any one of claims 1 to 3 , wherein the first direction and the second direction are directions orthogonal to each other in a horizontal plane. A turbo compressor that compresses gas by rotating an impeller with an electric motor,
A gear unit that transmits the rotational driving force of the electric motor to the impeller;
An oil tank for storing lubricating oil supplied to the gear unit below the gear unit;
A turbo compressor comprising the liquid level measuring device according to any one of claims 1 to 4 as a liquid level measuring device for measuring a liquid level in the oil tank. A condenser for liquefying the compressed refrigerant;
An evaporator that evaporates the liquefied refrigerant by the condenser and cools an object to be cooled;
A turbo compressor having a turbo compressor that compresses the refrigerant evaporated by the evaporator and supplies the compressed refrigerant to the condenser;
A turbo refrigerator having the turbo compressor according to claim 5 as the turbo compressor.

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