JPS59158392A - Operation control device for compressor - Google Patents

Abstract

PURPOSE:To improve saving of electric energy, by conducting optimal control of an operation circuit additionally including intermittent control by computer program control, and thereby automatically converting an operation to an optimal operation mode in accordance with an amount of air to be used. CONSTITUTION:A pressure sensor 10A and a two-way solenoid valve V are added to a prior art device. A computer inputs signals from the pressure sensors 10 and 10A, and decides condition of pressure fluctuation by a preset program to control a Y-4 magnet (not shown) for stopping and starting a prime mover 2 and controls solenoid valves 18, 11, V and 12, etc. A compressor is normally operated by stepped control, but in case of large fluctuation of an amount of air to be used, that is, large fluctuation of pressure, it is operated by non-stepped control for automatically stabilizing the fluctuation. On the other hand, in case of small fluctuation of pressure, an operation control is automatically converted to an intermittent control, so as to largely improve saving of electric energy.

Description

[Detailed Description of the Invention] This invention provides the following features:
The present invention relates to an air compressor operation control device that performs optimal control to minimize the power consumption of the air compressor.

As a conventional air compressor operation control device 11t, there are, for example, four types shown in FIG. (Special application 1986-2
(Refer to Publication No. 18412) This figure is an operation control system diagram for an oil-cooled rotary compressor, and 1 is the main body of this rotary compressor.
It is driven by a prime electric motor 2 via a belt drive 3. Since the compressor body 1 does not have built-in suction and discharge valves, a method is adopted in which the suction chamber 1S side of the compressor body 1 is closed during non-negative pre-operation, and a suction closing valve 4 is provided. ing. This valve 4 is a suction filter 1F.
Atmosphere A is inhaled through. Output side I of IE compressor body 1
An oil separator tank 6 is provided at D via a check valve 5, and oil in the discharged compressed air is separated by an annular separator element 7 in the upper part of the tank. The separated oil collects at the bottom of the tank 6, and only clean air is discharged from the outlet (kl!+60) at the secondary line pressure P via the minimum pressure valve 8 and stop valve 9.

The above minimum pressure valve 8 is a normally closed type and after the set pressure
The valve opens when the pressure exceeds 7 am. 10 is the discharge pressure (secondary side line pressure) detection switch, which is normally open and has a set pressure of 3.
2-way magnetic valves 11 and 3, closed at Icy/cm'';
-jj'di, attach the quality valve 12) and make the valve for j.

13 is the atmospheric discharge i from the above three-way '+'lL magnetic valve 12.
1J muffler, 14 is a pressure regulating valve, and this regulating valve is 7
It is set to open at 1η/cm'.

This kind of 1f:, 1 Iso 1, in order to alleviate problems such as noise caused by the high vacuum of the suction chamber 1S, allows a small amount of air to enter the suction side even during non-negative operation, so that it remains at Δ7. nil
In Separate Link 6 #)q: '(=I'+'B
The air 'A M of 4;
Air to Tsukuda i; 1 i + 11 Normally, oil 7 Output D of parator tank 6 Air is constantly pumped in.

Moreover, the oil at the bottom of the oil separator tank 6 is
Oil cooler 16, oil filter 17 and
, 19 are cooling fans directly coupled and driven by the drive motor 2. Note that in the piping in the figure, the reference numeral indicates each throttle nozzle.

Next, to explain the operation of this control system, the discharged compressed air containing oil from the compressor@1 is separated from oil by the separator element 7 in the oil separator tank 6, and the stop valve 9 is opened to send it to the user side. supply The return vibe 15 is closed by two-way and three-way solenoid valves 1112. When the secondary line pressure P rises to 7 kq/cm' during no-load operation, the pressure regulating valve 14 is activated and the suction closing valve 4 is closed, and the pressure increases to 8 ks'/am'.
When the pressure sensor 10 is activated, each solenoid valve 1 is activated.
1.12 is opened and a small amount of air is circulated in the unload power saving control mode. Next, when the use of compressed air is restarted on the user side and the pressure drops from 8kY/Crn' to 7kq/am'', the pressure sensor 10 operates to cut off the 41 forces of each solenoid valve 11.12. The suction shutoff valve 4 is closed and the suction shutoff valve 4 is opened again to return to the normal load operating state, and the two-step upward operating mode is repeated depending on the amount of air used on the user side.

However, in such a conventional operation control system, the operation of the pressure machine is controlled in two stages: normal load operation and unloading when there is no cargo, depending on the air consumption and agitation on the user side. 1), even if the air usage sensitivity on the user side is zero or extremely small, the actual
It is not possible to minimize the force and ft compared to that,
During this time, there was a drawback that power was wasted unnecessarily.

Figures 2 and 3 respectively show the amount of air used (1'4, which shows the relationship between 1 sq. and the ratio of power consumption, ≧).
Each Tsukuda change control 6 when the air tank capacity is 220 tons! ll
The relationship between the used air condensation (%) and the actual power ratio (%) according to the Jj formula, and since the electric power consumption 1 yen depends on the air tank capacity used, the air tank capacity (4 pairs) is shown in Figure 71 ￥3. Total 'city power ratio (-actual 1 (E power ratio x ratio of air used ()t)
(%) shows the relationship. -] In both figures, the dotted line A is the virtual intermittent control curve when the motive sweater is intermittent (stopped, started) depending on the air fiber used, and the dotted line B is the stepless control curve. The normal negative operation control curve, solid line C, shows the step control curve including the power saving unload operation. Curve A is close to the ideal characteristic that is extremely desirable at node MT, but in reality it is a virtual target line because it is functionally impossible to intermittent the motive sweater each time depending on the amount of air used. There is a large gap between curve B and curve C as well as this target line A.

This invention was made in view of these conventional problems, especially when the amount of air used is small.
In order to increase the effect, the optimum 1 [control is performed to approach the target line by performing program control using a combination coater and adding intermittent control, and the characteristics obtained by the configuration of the present invention to be described later are This is shown by the thick curved line in FIGS. 2 and 3.

In the following, the present invention will be explained based on the drawings. Figures 2 and 4 show an embodiment of the operation control device of the present invention in a system corresponding to Figure 1, and a system corresponding to Figure 1 and I+21- (corresponding) configuration. are indicated by the same reference numerals, and redundant explanation will be omitted. The difference from the conventional example shown in FIG. 1 is that a pressure sensor 11A and a two-way solenoid valve (2), shown by hatching, are added. Above pressure sensor 11A
is the same type as the conventional discharge IE sensor, and is normally open and closed at a set pressure of 8.51 (p/cm').
7. The above-mentioned two-way valve (711) located between the pressure regulating valve 14 and the pressure regulating valve 14 is energized to open.

The main feature of the present invention is that the sequence control selection method according to program control 1 is performed by a computer in order to perform the optimum same operation circuit I for the L operation circuit. explain.

This control method is based on the stage C1 and control f formula of the conventional example described above, and the L talker fluctuations (pressure, frequency, intermittent time, etc.) of the secondary line are constantly controlled by each pressure switch and timer. 1, then the motor 7-ta stop f1- (cut off e: lj
In this method, the computer performs control while determining the intoxication condition (control) or the condition for switching to each S, floor control. Judging the pressure fluctuation situation,
Y-4 Magnen for stopping and starting the drive motor ('M indication set'), each f1111f1. I4J electric Ti valve 18.
11-V.

12 etc., and its flowchart is shown in FIG. In other words, it is programmed to select each control method depending on the air usage situation, and is normally operated under stage 1 control, but if there are large fluctuations in air usage, that is, large pressure fluctuations. In order to stabilize this, stepless control is used. In addition, if the pressure fluctuation is small, the control is switched to intermittent control, which stops when the conditions for stopping are met. The purpose is to automatically switch these ()J changes.

In addition, at startup and stop 1-1, the suction is closed to perform no-load startup and stop the load ((load), thereby reducing the starting current at startup and also mitigating the shock applied to the compressor body.

Furthermore, since it stops F1 smoothly when it stops, the impact on the compressor body is alleviated, and the life of the compressor body can be extended. IL is turned off, and the solenoids of each 'm magnetic valve 18, 11.V, and 12 are set to SQL, 18, SQL, 11, SQL, V, and SQL, respectively.
.

12, the movements of each control device are programmed to perform the operations shown in Table G, for example.

Also, in Table 1, *A, *B in Figure 5: 1ili (ll
jl method switching, the fluctuation of the secondary line pressure is as above =:E
It is carried out at the time of f'l', and except for the following conditions, it is on the stage system side)
This is how it should be. In other words, (1) Conditions for switching to stepless 1-minute control (Fig. 5*
A) B) As shown in Figure 6, P is F3.5 ky
Time t to descend from /am' to 7 kHz /c, m' (*1→*2).

will switch to stepless 1i1J control within 5 seconds.

As shown in Figure 7, P rose from 7 kg/cm'' to 8.5 k7/am' and fell again to 7 ky/am' (Figure 5 *2 → *1 → *2) The number of times it is repeated is t2
= Switch to stepless control when counted 5 times within 60 seconds.

(2) Judgment conditions for switching to intermittent control (stop) (Figure 5*
B) As shown in Figure 8, P is 13.5 kg/cm'
(force) 7) Calculate the time t3 for the pressure to drop to 9/cm' (*1→*2), and set the time m5 and t4 when the pressure will stop in the next cycle according to Table 2. The stopping conditions are P) 8 ky/cm' and iM4115 after t4.
Stop.

Table 2 It goes without saying that the above example program can be modified by setting various conditions according to the needs of the user.

Also, the J of the present invention? The configuration of the one-turn control device is applicable not only to air compressors but also to other suitable 71-body compressors.

As explained above, according to the present invention, the operation control device 'Z of the air compressor can control the fluctuation of the secondary line pressure.
The pressure is constantly measured by the pressure sensor and the tires, and the computer uses the signal from the pressure sensor as human power to control the pressure fluctuation state using a preset Zlnviewer program, and uses the air in the secondary line. Activate each control solenoid valve one step at a time depending on the size of the amount, and then
The continuous +144ζ mode of the air compressor can be used for normal load operation without phase control, step control including unload operation, and intermittent ib'l CHI for stopping the driving electric motor, respectively, mutually and +1 reversely automatically. Since the compressor is configured to switch automatically, the compressor is automatically converted to the optimal operation mode depending on the amount of air consumed in the secondary line, and is simply controlled in two stages as in the conventional technology. As shown by the thick dashed line in FIGS. 2 and 3, the power saving effect can be significantly improved compared to the conventional method.

[Brief explanation of the drawing]

Figure 1 is a system diagram of an example of an operation control device for a conventional oil-cooled rotary air IE compressor, and Figures 2 and 3 are diagrams showing the relationship between air consumption and power consumption ratio for each operation control method. So, the second
The figure is a graph showing the ratio of used air to actual power, and FIG. 3 is a graph showing the ratio of air tank capacity to total power. FIG. 4 is a system diagram corresponding to FIG. 1 of an embodiment of the operation control device of the present invention, FIG. 5 is a flowchart thereof, and FIGS. 6 and 7 are respectively for stepless control switching judgment in the flowchart of FIG. FIG. 8 is a characteristic diagram showing the conditions for determining the intermittent control switching (whether to stop or not). 1...Rotary compressor body 2...Motive electric motor 4...Suction closing valve 6--Oil separator Tank 60...
...Outlet side (secondary side) 8...Minimum pressure valve 10.10
A...Pressure sensor 14...Pressure regulating valve 11.12.18. V... Solenoid switching valve A...
...Intake air P...Secondary side line pressure Fig. 1 8 2nd prisoner 9'7>F 2209 Fig. 3 Fig. 4 80541- Fig. 5

Claims (1)

[Claims] The pressure fluctuations in the secondary line 1a of the air compressor are constantly measured by a pressure sensor and a timer, and the computer uses the signal from the pressure switch as human power to control the pressure fluctuations by a preset computer programmer 18. Judging the condition, each commercial corporation J'R; operates a magnetic valve depending on the level of air usage in the secondary line, and changes the operating mode of the air compressor to non-operational load operation. An air system characterized by reciprocally, reversibly and automatically switching between step control, un-[J-mode operation] and continuous control for stopping the driving military motor, respectively. Royal machine operation control device.