JP5078762B2 - Screw compressor and maintenance method thereof - Google Patents

Description

  The present invention relates to, for example, a screw compressor that compresses refrigerant gas, and more particularly to a screw compressor that can maintain a bearing, which is a maintenance required component thereof, at an appropriate time and a maintenance method thereof.

  Regular maintenance of aged parts is indispensable in order to operate a screw compressor for a long period of time without failure. In particular, for rolling bearings, which are important components that dominate the life of screw compressors, the load and lubrication applied to the bearings have a significant effect on the life. As a manufacturer, the bearing replacement is most often urged after the lifetime (warranty period) calculated by applying the average usage conditions.

  Incidentally, there is a compressor system in which information is transmitted to a support center when each numerical information obtained from an operating state exceeds a preset threshold value (for example, see Patent Document 1).

  In addition, the bearing temperature and rotation speed of a rotating shaft such as an electric screw compressor are measured, and based on these bearing temperature and rotation speed, data on the life of the lubricant used in the bearing portion, particularly usable time, etc. There is also one that calculates (see, for example, Patent Document 2).

  In addition, the total rotational speed is obtained from the shaft rotational speed of the variable displacement compressor, the degree of deterioration of the lubricating oil is estimated from the internal temperature of the compressor and the operation time, the bearing life is estimated from these two factors, and the maintenance time is estimated. There is also a proposal that informs the user (see, for example, Patent Document 3).

  In addition, the maintenance time of the oil separation element is calculated from the differential pressure between the discharge air pressure of the oil separation and recovery device and the supply air pressure, and the suction air temperature of the compressor, the discharge air temperature of the oil separation and recovery device, and the oil temperature. There has also been proposed one that calculates the maintenance time of the oil filter from the flow rate of oil supplied to the compressor body obtained from the relationship (see, for example, Patent Document 4).

Japanese Patent Laying-Open No. 2007-205281 (FIG. 1) Japanese Patent Laying-Open No. 2005-30543 (FIG. 1) JP-A-6-249153 (FIG. 1) Japanese Patent Laying-Open No. 2003-254253 (FIG. 1)

  However, when a fixed life period (warranty period) calculated by applying the average usage conditions of the user is used to determine the period until the maintenance of the bearing, and when this fixed life period (warranty period) elapses, For those that encourage bearing replacement, users who use lighter loads than the average operating conditions will be encouraged to perform bearing replacement maintenance in a period shorter than the actual bearing life, There was a problem that maintenance was not promoted in an optimal period that could reduce costs.

  In addition, when each numerical information obtained from the operating state exceeds a preset threshold, the information is transmitted to the support center. For this reason, it was impossible to detect the maintenance time of the devices constituting the apparatus.

  In addition, it is possible to know the maintenance time of the lubricant if the life of the lubricant used for the bearing portion, that is, the usable time, is calculated based on the bearing temperature and the rotational speed. However, for example, it was impossible to know the life of a part that requires a lubricant (here, a bearing of an electric motor) and to know the maintenance time of the compressor directly.

  In addition, the total rotational speed is obtained from the shaft rotational speed of the compressor, the degree of deterioration of the lubricating oil is estimated from the internal temperature of the compressor and the operation time, and the bearing life is estimated from these two factors to notify the maintenance time. However, the load applied to the bearing and the viscosity of the lubricating oil, which are thought to have a significant effect on the bearing life, are not taken into account, leaving problems in terms of optimizing the bearing maintenance time. It was.

  In addition, the maintenance time of the oil separation element is calculated from the differential pressure between the discharge air pressure of the oil separation and recovery device and the supply air pressure, and the suction air temperature of the compressor, the discharge air temperature of the oil separation and recovery device, and the oil temperature. If the maintenance time of the oil filter is calculated from the flow rate of oil supplied to the compressor body obtained from the relationship, the life of the bearing itself built in the compressor cannot be known. I couldn't know the maintenance time.

  The technical problem of the present invention is to enable maintenance to be promoted in an optimum period that can reduce costs even under different use conditions depending on users.

  A screw compressor according to the present invention includes a suction port for sucking gas, a screw rotor and a gate rotor meshing with each other, a compression mechanism portion for compressing the sucked gas by the gate rotor, and a discharge port for discharging the compressed gas And a bearing that freely supports the screw rotor, a suction pressure sensor that measures the suction pressure, a discharge pressure sensor that measures the discharge pressure, and a pressure value measured by the suction pressure sensor and the discharge pressure sensor. Thrust load calculation means for calculating the thrust load to be calculated, and the thrust load cumulative value for measuring the operation time of the compression mechanism and calculating the cumulative value of the thrust load based on the measured operation time and the thrust load acting on the bearing The state of the bearing is determined based on the calculation means and at least the accumulated value of the thrust load, and the determined state becomes a predetermined state. If it is, are those comprising a bearing life judging means for notifying from notification means to that effect, the.

  The maintenance method of the screw compressor which concerns on this invention consists of the following structures. That is, a maintenance method for a screw compressor having a screw rotor supported by a bearing and a gate rotor meshing with the screw rotor, and compressing the sucked gas by the gate rotor, and measuring the suction pressure and the discharge pressure of the screw compressor. The thrust load acting on the bearing is calculated from each measured pressure value, the cumulative value of the thrust load is calculated based on the calculated thrust load and the operating time of the screw compressor, and at least the calculated cumulative value of the thrust load The state of the bearing is determined based on the above, and when the determined state of the bearing is in a predetermined state, a notification to that effect is given.

  According to the present invention, the suction pressure and the discharge pressure of the screw compressor are measured, the thrust load acting on the bearing is calculated from the measured pressure values, and the calculated thrust load and the operation time of the screw compressor are calculated. Calculate the cumulative value of the thrust load, and compare at least the calculated cumulative value of the thrust load with the bearing life judgment value that can be obtained from the calculation formula recommended by the bearing manufacturer, for example. When the determined bearing state is in a predetermined state, the notification means notifies that, so the thrust load acting on the screw compressor bearing is the average usage condition assumed by the manufacturer. How much load is generated with respect to the bearing load at the same time, and at what time ratio the operating state with the thrust load is generated in the total operating time It becomes possible to know Runoka, the maintenance timing of the screw compressor itself can know the correct, it is possible to prompt maintenance of the bearing exchange at the optimum time without excess or shortage be different conditions of use by a user.

Embodiment 1 FIG.
The present invention will be described below with reference to illustrated embodiments.
1 is a cross-sectional view showing the configuration of a screw compressor according to Embodiment 1 of the present invention, FIG. 2 is an explanatory view of the operation of the compression mechanism, and FIG. 3 is an explanatory view of a thrust load acting on the bearing. .

  The screw compressor 1 of the present embodiment includes a casing 10 in which a screw shaft 1e is supported via rolling bearings (hereinafter simply referred to as bearings) 1f and 1g, and a screw rotor on one end side of the screw shaft 1e. 1c is arranged, and two gate rotors A and B (FIG. 2) are arranged at right angles to both sides of the screw rotor 1c, and the compression rotor is constituted by the screw rotor 1c and the gate rotors A and B. ing. The screw rotor 1c is driven by an electric motor 1d connected by a screw shaft 1e, but the rotation is supported by bearings 1f and 1g.

  More specifically, the screw rotor 1c has a plurality of tooth grooves, and the gate rotors A and B on both sides are engaged with the tooth grooves, and the screw rotor 1c and the gate rotors A and B Two compression chambers are formed. That is, the gate rotors A and B rotate in a passive manner along the tooth surface of the screw rotor 1c as is well known, and the screw rotors 1c of FIG. 2 (a) → (b) → (c). It has a function of blocking the space between the screw groove 1h and the casing 10 and compressing the fluid (for example, refrigerant gas) in this space. The fluid is sucked into the casing 10 from the suction port 1a, compressed by the compression mechanism as described above, and discharged from the casing 10 through the discharge port 1b. Therefore, one end portion (a part of the left end in FIG. 1) of the screw rotor 1c in the casing 10 is exposed to the discharge gas (high pressure gas), and the other end portion (the right end portion in FIG. 1) of the screw rotor 1c in the casing 10 is exposed. ) Is exposed to suction gas (low pressure gas), and a pressure difference is generated between them. For this reason, the screw shaft 1e that is pivotally supported by the bearings 1f and 1g and integrated with the screw rotor 1c has a load of an axial component due to a pressure difference between both ends of the screw rotor during operation of the screw compressor 1 (FIG. 3). A thrust load (indicated by a thick arrow) is generated. That is, the bearings 1f and 1g bear not only the radial load but also a thrust load (component force) caused by a pressure difference between the high pressure and the low pressure. Therefore, by measuring the pressure values of the high pressure and the low pressure during operation, it is possible to calculate the thrust load that the bearing actually handles each time by calculation. Since this thrust load causes deterioration of the bearings 1f and 1g, in this embodiment, the maintenance time of the bearings 1f and 1g is determined and notified by detecting this thrust load.

  In order to realize this, in the present embodiment, the suction pressure sensor 2 that measures the suction pressure, the discharge pressure sensor 3 that measures the discharge pressure, and the pressure values measured by the suction pressure sensor 2 and the discharge pressure sensor 3 are used as bearings. The thrust load calculating means 4 for calculating the thrust load acting on 1f and 1g and the operation time of the compression mechanism section are measured by, for example, the operation time of the electric motor 1d, and the measured operation time of the compression mechanism section and the bearings 1f and 1g are measured. Based on the acting thrust load, the thrust load cumulative value is calculated and stored in the storage means 6. The thrust load cumulative value is stored in the storage means 6. The bearing life is judged by comparing with the accumulated value (bearing life judgment value). If the cumulative value of the thrust load exceeds the bearing life judgment value, the bearing life It is provided with bearing life judging means (7) for notifying from notification means 8 of alarms, etc., as has brought.

  Next, a maintenance method for the screw compressor of the present embodiment configured as described above will be described with reference to FIGS. First, when the motor 1d is driven and the compression mechanism, that is, the screw compressor 1, starts operation, the suction pressure and the discharge pressure of the screw compressor 1 are measured, and the thrust acting on the bearings 1f and 1g from the measured pressure values. Calculate the load. Next, the operation time of the screw compressor 1 is measured, and a cumulative value of the thrust load is calculated based on the measured operation time and the calculated thrust load. Next, by comparing the calculated thrust load cumulative value with a bearing life judgment value that can be obtained from, for example, a bearing manufacturer's recommended calculation formula, the bearing life is judged, and the thrust load cumulative value is If it exceeds the bearing life determination value, it is determined that the bearing is at the end of its life, and the notification means 8 notifies that the maintenance time has come.

  Thus, according to the present embodiment, the thrust load acting on the bearings 1f and 1g is calculated from the suction pressure value and the discharge pressure value of the screw compressor, and based on the calculated thrust load and the operating time of the screw compressor. Since the cumulative value of thrust load is calculated and the calculated cumulative value of thrust load is compared with the bearing life judgment value, the bearing life is judged and the maintenance time of the bearings 1f and 1g is determined. The magnitude of the thrust load acting on the bearings 1f, 1g of the screw compressor 1 relative to the bearing load under the average usage conditions assumed by the manufacturer, and the thrust load It is also possible to know at what time ratio the operating state of the engine occurs during the total operating time, and the maintenance time of the screw compressor 1 itself is appropriate It is possible to know. For this reason, maintenance of bearing replacement can be promoted in an optimal period that is not excessive or insufficient even under different use conditions depending on the user.

Embodiment 2. FIG.
FIG. 4 is a cross-sectional view showing the configuration of the screw compressor according to Embodiment 2 of the present invention. In the figure, the same parts as those in Embodiment 1 are given the same reference numerals.

  The screw compressor of the present embodiment includes a temperature sensor 11 that measures the temperature of the lubricating oil supplied to the bearings 1f and 1g in the screw compressor 1 of the first embodiment, and a lubricating oil temperature measured by the temperature sensor 11. And a lubricating oil viscosity determining means 9 for determining the viscosity of the bearing so that the bearing life determining means 7A determines the bearing life in consideration of not only the cumulative value of the thrust load but also the viscosity of the lubricating oil. However, the configuration is the same as that of the first embodiment, and all the functions of the first embodiment are provided.

  In the screw compressor of the present embodiment, the bearing life determining means 7A determines the bearing life in consideration of not only the cumulative value of the thrust load but also the viscosity of the lubricating oil. The maintenance of bearing replacement can be promoted in a more optimal period considering the influence on the bearing.

It is sectional drawing which shows the structure of the screw compressor which concerns on Embodiment 1 of this invention. It is explanatory drawing of operation | movement of the compression mechanism part of the screw compressor which concerns on Embodiment 1 of this invention. It is explanatory drawing of the thrust load which acts on the bearing of the screw compressor which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the structure of the screw compressor which concerns on Embodiment 2 of this invention.

Explanation of symbols

  1 screw compressor, 1a suction port, 1b discharge port, 1c screw rotor (compression mechanism), 1f, 1g bearing, A, B gate rotor (compression mechanism), 2 suction pressure sensor, 3 discharge pressure sensor, 4 thrust Load calculating means, 5 Thrust load accumulated value calculating means, 7, 7A Bearing life determining means, 8 Notifying means, 9 Lubricating oil viscosity determining means, 11 Temperature sensor.

Claims (4)

An inlet for inhaling gas;
A compression mechanism that has a screw rotor and a gate rotor meshing with each other, and compresses the sucked gas by the gate rotor;
A discharge port for discharging compressed gas;
A bearing that rotatably supports the screw rotor;
A suction pressure sensor for measuring the suction pressure;
A discharge pressure sensor for measuring the discharge pressure;
Thrust load calculating means for calculating a thrust load acting on the bearing from each pressure value measured by the suction pressure sensor and the discharge pressure sensor;
A thrust load cumulative value calculating means for measuring an operating time of the compression mechanism section and calculating a cumulative value of the thrust load based on the measured operating time and a thrust load acting on the bearing;
Bearing life determination means for determining the state of the bearing based on at least the cumulative value of the thrust load, and informing the fact from the notification means when the determined bearing state is a predetermined state;
A screw compressor comprising: A temperature sensor for measuring the temperature of lubricating oil supplied to the bearing;
Lubricating oil viscosity determining means for determining the viscosity from the lubricating oil temperature measured by the temperature sensor;
The screw compressor according to claim 1, further comprising: determining the state of the bearing based on the cumulative value of the thrust load and the viscosity. A maintenance method for a screw compressor having a screw rotor supported by a bearing and a gate rotor meshing with the screw rotor, wherein the sucked gas is compressed by the gate rotor,
The suction pressure and discharge pressure of the screw compressor are measured, the thrust load acting on the bearing is calculated from the measured pressure values, and the thrust load is accumulated based on the calculated thrust load and the operating time of the screw compressor. A value is calculated, and the state of the bearing is determined based on at least the calculated cumulative value of the thrust load. When the determined state of the bearing is in a predetermined state, the notification means notifies the fact. The maintenance method of the screw compressor characterized.   The temperature of the lubricating oil supplied to the bearing is measured, the viscosity is determined from the measured lubricating oil temperature, and the state of the bearing is determined based on the cumulative value of the thrust load and the viscosity. The maintenance method of the screw compressor of Claim 3 to do.

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