JPH0819919B2 - Surging occurrence predicted time display device and surging prevention device for turbo refrigerator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a surging occurrence predicted time display device and a surging prevention device for a turbo refrigerator.

(Prior Art) Conventionally, when a surging occurs in a turbo chiller, the surging is automatically detected by cutting the surging to detect the surging and cutting the discharge pressure. The one described in Japanese Patent Laid-Open No. 58-15639 is known, and as disclosed in FIG. 9, the one disclosed in Japanese Patent Laid-Open No. 58-15639 is a pressure detector for detecting a sudden decrease in the discharge pressure in the discharge pipe (A). (B) is interposed, and when there is a sudden pressure drop of 2 or more times within a preset time, a surging determination circuit (C) for determining surging is provided, and the output from this determination circuit (C) The surging prevention device (D) is operated by.

Further, as a preventive device for preventing the occurrence of surging before the occurrence of surging, for example, one stored in Japanese Utility Model Laid-Open No. 63-31292 is known, and the one described in this publication is as shown in FIG. In addition, a surging prevention valve (F) is provided in the middle of the branch pipe branching from the high pressure gas region of the turbo compressor (E), and an input to a motor (M) provided in the turbo compressor (E) is provided. A measuring device (G) for measuring current is provided, and an adjusting device (H) for comparing the input current measured by the measuring device (G) with a reference current set in relation to the discharge pressure and the air volume is provided. The surging prevention valve (F) is operated based on the output from the regulator (H) to prevent surging on the turbo compressor (E) side.

(Problems to be solved by the invention) However, in the former case (Japanese Patent Publication No. 58-15639), surging does not automatically occur until surging occurs before surging occurs. It cannot be prevented, and surging cannot be predicted.

In the latter (No. Sho 63-31292), the input current to the motor (M) is compared with the reference current preset based on the discharge pressure and the like by the regulator (H). Since the surging prevention valve (F) is operated by the output from the regulator (H), the former problem described above can be solved. There is a proportional relationship not only with the base discharge pressure but also with the suction pressure, so the error in the surging head when the suction pressure fluctuates increases, and the reference current based on the air volume and discharge pressure is also present. In the case of predicting surging based on, the change in air flow is similar to current electrification.However, this approximate value is affected by voltage fluctuations and an error occurs, so there is a problem that accurate surging cannot be predicted. It was

The present invention, as a result of performing various tests to solve the above problems, in the turbo compressor, the flow on the outlet side of the impeller is turbulent as it approaches the surging line, and the diffuser inlet portion facing the outlet side of the impeller. It is known that the differential pressure increase phenomenon occurs between the hub side pressure and the shroud side pressure, which are opposite to each other in the motor axis direction, in other words, when the engine is operated sufficiently away from the surging line. , The turbulence on the outlet side of the impeller does not occur, and the flow is balanced, so the differential pressure between the hub side pressure and the shroud side pressure at the diffuser inlet part becomes almost zero, while on the surging line. When approaching, it is known that turbulence occurs in the flow and the differential pressure increases, that is, there is a correlation between the differential pressure and surging. By utilizing the fact is to be able to predict the surging occurrence of a turbo compressor side.

A first object of the present invention is to provide a surging occurrence predicted time display device capable of accurately predicting the occurrence of surging with a simple configuration, thereby appropriately performing a treatment for preventing surging based on an accurate prediction result. A second object of the present invention is to provide a surging prevention device capable of accurately predicting the occurrence of surging and automatically preventing the occurrence of surging.

(Means for Solving the Problem) In order to achieve the first object, the surging occurrence predicted time display device of the present invention is configured such that a turbo compressor (1) has an impeller (13) rotating around a motor shaft and a diffuser ( 14) and a differential pressure detector (5) for detecting the differential pressure between the shroud side pressure and the hub side pressure, which face each other in the motor axial direction near the flow path inlet of the diffuser (14), and this difference. A controller (6), which is connected to the controller (6), which calculates a differential pressure from the detection result from the pressure detector (5) and calculates and predicts the time from the change in the differential pressure to the occurrence of surging, and the controller (6). (6)
The display (7) for displaying the surging occurrence predicted time calculated in step (4) is provided.

Further, in order to achieve the second object, the surging prevention device of the present invention is provided with an impeller (13) and a diffuser (14) that rotate around a motor shaft in a turbo compressor (1), and the diffuser ( 14) A differential pressure detector (5) that detects the differential pressure between the shroud side pressure and the hub side pressure that face each other in the motor axial direction near the flow path inlet, and the detection result from this differential pressure detector (5). A controller (6) that calculates a differential pressure from the differential pressure and calculates and predicts the time from the change in the differential pressure to the occurrence of surging, and an opening that adjusts the opening of the suction vane (15) in the turbo compressor (1). An adjusting mechanism (16) is provided, and an operation signal is output to the opening adjusting mechanism (16) when the differential pressure between the shroud side pressure and the hub side pressure approaches the surging occurrence differential pressure to the controller (6). Shi , Than is provided an output unit (8) for controlling the opening degree of the vane (15) in the opening direction.

(Operation) In the invention of claim 1, the differential pressure between the shroud-side pressure and the hub-side pressure, which face each other in the axial direction of the motor in the vicinity of the flow path inlet of the diffuser (14) of the turbo compressor (1), is the difference. The pressure is detected by the pressure detector (5) and is input to the controller (6). The controller (6) calculates the differential pressure change, and the time to surging is predicted based on the calculated value, and the surging occurs. The estimated time is accurately displayed on the display (7).

Therefore, the user can take appropriate surging prevention measures based on the surging occurrence predicted time displayed on the display (7). That is, the surging on the compressor (1) side means that when air is mixed in the refrigerating pipe, when scale is attached in the refrigerating pipe, or when the amount of water in the cooling pipe connected to the condenser of the refrigerating cycle is When it decreases, it mainly occurs, therefore, based on the accurate surging occurrence prediction time, operate the extraction pump, remove the scale, adjust the water amount, etc., It is possible to prevent the occurrence of appropriate surging.

Further, in the invention of claim 2, the differential pressure between the shroud side pressure and the hub side pressure, which face each other in the axial direction of the motor in the vicinity of the flow path inlet of the diffuser (14) of the turbo compressor (1), is the differential pressure. When the differential pressure change is detected by the detector (5) and is input to the controller (6), the differential pressure change is calculated by the controller (6), and the differential pressure approaches the surging-generated differential pressure based on this calculation unit. An output signal (8) of the controller (6) outputs an operation signal to the opening adjustment mechanism (16) to control the vane (15) in the opening direction to open the vane (15). As a result, the surging head on the side of the compressor (1) moves away from the surging grin, and surging on the compressor (1) is automatically avoided.

(Example) FIG. 1 shows a refrigeration cycle of a turbo refrigerator,
The condenser (2), the expansion valve (3), and the evaporation section (4) are connected to the turbo compressor (1) via refrigeration pipes, respectively. The condenser (2) is connected to a heating air conditioner (2A) for exchanging heat with the refrigerant passing through the condenser (2) to take out hot water, and the condenser (2) ) Is connected to a cooling tower (2B) for cooling the passing refrigerant, and the evaporator (4) exchanges heat with the refrigerant passing through the evaporator (4) to provide cooling water. The air conditioner for cooling (4A) for taking out is connected.

As shown in detail in FIG. 2, the turbo compressor (1) has a hub (via a gear mount assembly (12) interlocking with a motor (not shown) at the center of the housing (11). The impeller (13) provided with 13a) is rotatably supported, and at the outlet (13b) side of the impeller (13),
While facing the diffuser (14) having a hub-side inlet and a shroud-side inlet, a suction vane (15) is arranged on the inlet (13c) side of the impeller (13),
The capacity control operation of the compressor (1) is enabled by adjusting the opening degree of the vane (15) by the opening degree adjusting mechanism (16) including a motor. In the figure, (17)
Is a ring gear coupling, (18) is an oil pump,
(19) is an oil pipe and (20) is a discharge pipe.

In the above turbo refrigerator, as shown in detail in FIGS. 2 and 3, the diffuser (14)
A hub-side conduit (21) for guiding the hub-side pressure and a shroud-side pressure conduit (22) for guiding the shroud-side pressure are opened at positions facing each other in the motor axial direction near the inlet of each of the conduits. (21) (22) is connected to the differential pressure detector (5), and the difference between the hub side pressure and the shroud side pressure detected by the detector (5) is connected to the output side of the detector (5). A controller (6) that calculates a pressure change and calculates and predicts a time to the occurrence of surging based on the calculated value is connected to the controller (6), and the controller (6) calculates an output side of the controller (6). A display (7) for displaying the surging occurrence predicted time is connected to form a surging occurrence predicted time display device.

Then, based on the surging occurrence prediction time displayed on the display (7), for example, a bleeding pump is operated to bleed air in the refrigerating pipe, and adhered scale in the refrigerating pipe is removed. By adjusting the amount of cooling water from the cooling tower (2B) to the condenser (2), it is possible to prevent surging from occurring. In this embodiment, the extraction pump is operated.

Further, the controller (6) includes an opening adjustment mechanism (16) when the differential pressure between the shroud side pressure and the hub side pressure detected by the differential pressure detector (5) approaches a surging generated differential pressure. ) Is provided with an output signal (8) for forcibly controlling the opening of the vane (15) in the opening direction, and when the compressor (1) approaches the surging occurrence region, By outputting an operation signal from the output section (8) to the opening adjustment mechanism (16) to open the vane (15), the surging head on the compressor (1) side is moved away from the surging line, Surging in the compressor (1) is automatically avoided.

Fig. 4 shows a capacity-controlled turbo compressor (1) with the heat insulation head (kcal / kg) on the vertical axis and the air volume (m ³ / min) on the horizontal axis.
Shows the surging occurrence state. Therefore, the air flow rate on the turbo compressor (1) side is controlled by the opening of the vane (15), and the head is raised during the capacity control operation of the compressor (1) corresponding to the opening of the vane. Accompanying
The air volume line corresponding to each vane opening (10% to 100%) approaches the surging line shown in the figure, and when it exceeds this surging line, surging occurs on the compressor (1) side. is there.

At this point, the differential pressure between the hub-side pressure and the shroud-side pressure increases as each of the air flow lines approaches the surging line, and the differential pressure on this surging line is
Regardless of the opening of the vane (15), the pressure difference is almost the same (0.28 kg / cm ^{2 in} FIG. 4).

That is, as shown in FIG. 5, as the head (kcal / kg) of the turbo compressor (1) rises, distortion occurs in the flow passing through the inlet of the diffuser (14), Therefore, the pressure difference between the hub side pressure near the inlet and the shroud side pressure increases, and in the turbo compressor (1) of the same model, when the vane opening is 10, 20, 40, 80, 100%, Although the change is different, in any case, the same differential pressure increases, and surging occurs in a region exceeding a predetermined differential pressure (for example, 0.28 kg / cm ² ).

Further, also in the turbo compressor (1) in which the shape of the diffuser (14) is different, as shown in FIG. 6, as the head rises, the differential pressure corresponding to each vane opening increases, and in this case The differential pressure at which surging occurs is 0.38 kg / cm ² .

Therefore, the differential pressure at the time of surging in various turbo compressors (1) is previously obtained and set, and the differential pressure change in the diffuser (14) detected by the differential pressure detector (5) is adjusted by the controller (6). ), The time until the occurrence of surging is predicted by comparing and calculating the surging occurrence time, and the surging occurrence predicted time is displayed on the display (7). Of.

In addition, the differential pressure at the time of the surging is obtained in advance, and the differential pressure lower than this differential pressure on the surging line, for example, as shown in FIG. 4, the differential pressure on the surging line is 0.28 kg / c.
In the case of m ² , as shown by the dotted line in the figure, 0.26 kg / cm ² lower than the differential pressure is input to the controller (6) as the set differential pressure, and the input set differential pressure, The hub side pressure of the diffuser (14) detected by the differential pressure detector (5) and the measured differential pressure of the shroud side pressure are compared by the controller (6), and this measured differential pressure reaches the set differential pressure. At this time, an output signal (8) of the controller (6) outputs an operation signal to the opening adjustment mechanism (16) of the vane (15) to forcibly open the vane (15). Four
As is clear from the figure, by moving the surging head on the compressor (1) side away from the surging life, surging on the compressor (1) can be automatically avoided.

Further, regardless of the opening of the vane (15), the differential pressure on the surging line is substantially constant, and based on the set differential pressure lower than this differential pressure, the opening operation of the vane (15) by the controller (6) is performed. Therefore, even if any capacity control operation is performed, for example, as shown in FIG.
Even when the capacity control operation is performed with the vane opening of 10%, the opening operation of the vane (15) is performed by the controller (6) when approaching the surging line, so that the compressor (1) is opened. Surging can be surely prevented, and thus the continuous operation time of the compressor (1) can be lengthened.

Next, the above operation will be described based on the flowchart shown in FIG.

First, at the time of steady operation (step 2) accompanying the start (step 1), in step 3, the pressure on the shroud side is
And P ₁₀ and the hub side pressure P ₂₀ is read into the controller (6), there is the initialization is performed in step 4 after this, the initial setting, the counter I = 0, the differential pressure ΔP of the surge line _MAX , measured pressure difference between the shroud side pressure and the hub side pressure at the start of operation ΔPI = ABS
(Absolute _{value) · (P 10 -P 20)} , the alarm output differential pressure [Delta] P _aL, set differential pressure [Delta] P _MAX · N was slightly lower the than the differential pressure [Delta] P _MAX is entered when outputting an alarm.

Next, after performing the above initial setting, in step 5, the time ΔT of the minute order is set by the timer,
Set the counter to I = I + 1. Further, in step 6, the shroud-side pressure P ₁ I and the hub-side pressure P ₂ I at each time are read. Then, in step 7, the differential pressure change (pressure gradient) m = (P ₁ IP ₂ I) / Δ based on the differential pressure ΔPI = ABS · (P ₁ IP ₂ I) at each time.
T is calculated by the controller (6), and the surging occurrence prediction time T = ΔP _MAX −ΔPI) / m based on the calculation result.
Is calculated and this surging occurrence predicted time T is displayed on the display (7) in step 8.

Next, in step 9, it is judged whether or not the differential pressure ΔPI is higher than the alarm output differential pressure ΔP _aL , and if no, the routine from step 5 is repeated, and if yes, in step 10. , The display (7)
Alternatively, a surging alarm is displayed on another display device, and in step 11, the extraction pump is driven. If YES in step 9, it is determined in step 12 whether or not the differential pressure ΔPI is smaller than the set differential pressure ΔP _MAX · N. If YES, in step 13, the vane ( 15) control is performed,
On the other hand, in the case of No, the differential pressure ΔPI is the set differential pressure ΔP _MAX
Whether it is greater than or equal to N is determined in step 14, and if no, the routine from step 5 is repeated, and in the case of yes, it is determined that the critical area is reached and the compressor ( 1) is stopped and this stop is displayed on the display (7).

Further, the vane control in step 13 is performed based on the subroutine shown in FIG. 8. That is, first, in step 21, it is read that the current vane opening ΦK is K = 0. Next, in step 22, it is judged whether or not the differential pressure ΔPI is higher than the alarm output differential pressure ΔP _aL , and if no, the routine from step 21 is repeated, and if yes,
In step 23, the vane opening ΦK = ΦK _-1 + Δ
Φ (amount of change in opening) is set, and thereafter, the motor current IM of the compressor (1) is read in step 24, and then, in step 25, the motor current IM becomes its rated current I _ST . It is determined whether or not it is smaller than the value multiplied by the coefficient 1.05. If the result is yes, the routine from step 21 is repeated. If the result is no, in step 26, the opening of the vane (15) is maintained. Is done.

(Effects of the Invention) As described above, in the surging occurrence predicted time display device of the present invention, the turbo compressor (1) is provided with the impeller (13) rotating around the motor shaft and the diffuser (14), A differential pressure detector (5) for detecting the differential pressure between the pressure on the shroud side and the pressure on the hub side, which face each other in the motor axial direction near the flow path inlet of the diffuser (14).
And a controller (6) that calculates a differential pressure from the detection result from the differential pressure detector (5) and calculates and predicts the time from the change in the differential pressure to the occurrence of surging, and is connected to the controller (6) A display (7) for displaying the surging occurrence predicted time calculated by the controller (6)
Since the provision of and is provided, it is possible to accurately predict the occurrence of surging on the compressor (1) side and display the accurate predicted time on the display (7).

Therefore, the user can take appropriate surging prevention measures before surging occurs based on the surging occurrence predicted time displayed on the display (7).

Further, in the surging prevention device of the present invention, the turbo compressor (1) has an impeller (13) rotating around a motor shaft.
And a diffuser (14), and a differential pressure detector (5) for detecting the differential pressure between the shroud side pressure and the hub side pressure, which face each other in the motor axial direction near the flow path inlet of the diffuser (14). , This differential pressure detector (5)
The controller (6), which calculates the differential pressure from the detection result from, and calculates and predicts the time from this differential pressure change to the occurrence of surging, and the opening of the suction vane (15) in the turbo compressor (1). An opening adjustment mechanism (16) for adjusting is provided, and when the differential pressure between the shroud side pressure and the hub side pressure approaches the surging occurrence differential pressure in the controller (6), the opening adjustment mechanism (16) is provided. Output the operation signal,
Since the output part (8) for controlling the opening degree of the vane (15) in the opening direction is provided, the shroud side facing each other in the motor axial direction near the flow path inlet of the diffuser (14) of the turbo compressor (1). The differential pressure between the pressure and the hub-side pressure is detected by the differential pressure detector (5) and input to the controller (6), the differential pressure change is calculated by the controller (6), and based on this calculated value When the differential pressure approaches the surging-generated differential pressure, an operation signal is output from the output section (8) of the controller (6) to the opening adjustment mechanism (16) to open the vane (15) in the opening direction. The surging head on the compressor (1) side can be controlled away from the surging line by controlling and opening the vane (15) to automatically avoid surging on the compressor (1).

[Brief description of drawings]

FIG. 1 is a refrigeration circuit diagram of a turbo refrigerator to which a surging prevention device of the present invention is applied, FIG. 2 is a sectional view showing a turbo compressor of the refrigerator, FIG. 3 is an enlarged sectional view of essential parts, and FIG. FIG. 7 is an explanatory diagram for explaining a surging occurrence state, FIGS. 5 and 6 are explanatory diagrams showing a relationship between a heat insulating head and a differential pressure of compressors of different models, and FIG. 7 is a control mode of the preventive device. FIG. 8 is a flowchart showing a subroutine for performing vane control, and FIGS. 9 and 10 are drawings for explaining a conventional example. (1) …… Turbo compressor (13) …… Impeller (14) …… Diffuser (15) …… Suction vane (16) …… Opening adjustment mechanism (5) …… Differential pressure detector (6) …… Controller (7) …… Display (8) …… Output section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-181096 (JP, A) JP-A-58-15793 (JP, A) Actually open 49-123606 (JP, U) Actual-open Sho 63- 31292 (JP, U) Actual development Sho 59-156199 (JP, U)

Claims (2)

[Claims] 1. A turbo compressor (1) is provided with an impeller (13) rotating around a motor shaft and a diffuser (14), and opposed to each other in the motor axial direction in the vicinity of a flow path inlet of the diffuser (14). The differential pressure detector (5) that detects the differential pressure between the shroud side pressure and the hub side pressure, and the differential pressure is calculated from the detection result from this differential pressure detector (5), and surging occurs from this differential pressure change. And a display (7) connected to the controller (6) for displaying the surging occurrence predicted time calculated by the controller (6). A characteristic display device for predicting surging occurrence in turbo refrigerators. 2. A turbo compressor (1) is provided with an impeller (13) rotating around a motor shaft and a diffuser (14), and opposed to each other in the motor axial direction in the vicinity of a flow path inlet of the diffuser (14). The differential pressure detector (5) that detects the differential pressure between the shroud side pressure and the hub side pressure, and the differential pressure is calculated from the detection result from this differential pressure detector (5), and surging occurs from this differential pressure change. (6) that calculates and predicts the time to reach the suction vane (1) in the turbo compressor (1).
An opening adjustment mechanism (16) for adjusting the opening of 5) is provided, and when the differential pressure between the shroud side pressure and the hub side pressure approaches the surging occurrence differential pressure in the controller (6), A surging prevention device for a turbo refrigerator, comprising: an output unit (8) for outputting an operation signal to the adjusting mechanism (16) to control the opening of the vane (15) in the opening direction.