JPS5949381A - Load control device - Google Patents

Abstract

PURPOSE:To compensate abnormal pressure reduction in a short time, by switching an unloaded operation of all compressors to a fully loaded operation upon detecting rapid pressure reduction, and carrying out capacity control with a first unloaded compressor. CONSTITUTION:Under first, second and third unloaded operations of compressors, when air consumption is rapidly increased to abnormally reduce pressure, a relay 81 is excited to switch on a contact point 81a1 of an abnormal pressure reduction detecting circuit and to release self-hold of relays 4F, 52 and 55, thereby operating all the compressors under fully loaded condition. At this time, a stepping relay SP2 of an operation stop order determining circuit is positioned at 3. A relay B repeats on-off operation at its contact point Ba1 every set time t'' sec of a timer Tsp to advance a stepping relay SP1 by one step. When the relay SP2 is positioned at 3, the stepping relay SP1 is stopped at a position of 1, and a contact point B8a2 is switched on to carry out capacity control with the first unloaded compressor.

Description

[Detailed description of the invention] The present invention relates to a compressor number control device.

In general, a plurality of compressors are installed, and these are operated while being controlled appropriately according to the needs of the company, and the three air compressors are stably discharged to a desired pressure, and this is used as money.

However, in the past, this unique German unit control system had the disadvantage of preventing the pressure from increasing due to a decrease in the amount of air consumed, as well as averaging the operating time of each compressor, and allowing only one compressor to be unloaded and fully loaded. In order to prevent this from being repeated in a concentrated manner, the valley congressors are unloaded one by one at regular intervals (unnegative state) while the pressure is rising, and finally unloaded. The loaded compressor was in charge of capacity control, and the other unloading machines were configured to continue unloading until they stopped, regardless of the pressure, and to stop at regular intervals. Therefore, if the pressure has been rising for a long time, multiple compressors may be unloaded, and when several compressors are unloaded, the amount of air consumed increases and the pressure suddenly drops. In this case, the other compressors, except for the last unloaded compressor, cannot return to full load, resulting in an abnormal drop in pressure.

The present invention has been proposed in view of the above points, and when a sudden pressure drop is detected when multiple unloading machines occur due to a long-term pressure rise, all of the combination rack salmon machines that are in the state of continuous unloading are detected. At the same time as the compressor is fully loaded, the first compressor to be unloaded in the unloading machine is in charge of capacity control, and the abnormal pressure drop is recovered within a short period of time, thereby eliminating the above-mentioned drawbacks of the conventional method. The purpose is to provide a device for controlling the number of units.

Hereinafter, the present invention will be fully described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram showing the entirety of the present invention, and in the figure C+~
The first to third compressors are connected to C3, and the collecting pipe 1 is connected to the discharge side of these compressors C1 to C3, respectively, and the discharge system is combined into one pipe, and the valley compressors C1 to C3 are connected to each other.
The compressed air from C3 is once sent into the collecting valve 2 and then discharged to the outside via the valve 3 and the valve 4. The collection tank 2 is equipped with pressure regulators PS, ~PS4 that detect the internal pressure and turn on and off when the pressure reaches the pressure value of 1, thereby activating all the relays described later. There is. If the set pressures of these pressure switches PS, ~PS4 are all P, -P4, then the valley pressure switch PS.

P1 means abnormal pressure low - 10, P2 means pressure decrease, P3 means pressure increase, and P4 means abnormal pressure increase. Note that in the above, the number of compressors is not limited to three.

Figure 2 0) shows the connection Bk between the valley lever and the relay. The contact signals of each pressure valve suite PS1 to PS4 are applied to the relays 81 to 84 through five conversion circuits and are connected so as to excite them. It is constructed such that it is energized when the pressure state P is as follows.

P≧P, ... Relay 83 excitation p, > p ≧ P3 ... ... Re - 8
4 FflJ Magnetic P2≧P > P +・・・・・・
Relay 82 excitation P≦P, . . . Relay 81 excitation, etc. The above relationship is illustrated in an easy-to-understand diagram as shown in Fig. 2)).

Figure 3 shows the starting and stopping order of each compressor C8 to C8.
Cs→C7--1, while the stop j bile order is #3
It is configured to stop in the order of movement, that is, in the order of C1 -> C7 -> C3 -> C4-m-.

Also, the unloading order of compressors C4 to C3 is C
The train is operated in the following order: 1→C2→C3→C1-m-. Note that the compressor that will be unloaded first can be selected by operation before operation.

Next, the overall operation of the present invention will be explained with reference to FIG. Suppose now that the pressure has increased after the start of interlocking operation, and several compressors are unloaded. When the predetermined unloading time elapses in this state (see b), the first compressor to be unloaded in the unloading machine is stopped (see c). In other words, in order to stop the compressor δ, the VC motor and the compressor itself are overheated, so the cooling time is a fixed period of about 3 to 5 minutes...
], this is because it is necessary to stop the compressor after operating it with unloading. Next, the pressure is judged (d &"teru), but if the pressure is rising, as shown in the solid line thread path, if the degree of pressure rise is P≧P4, the pressure will not rise abnormally. (Refer to e and f), the degree of pressure increase in the trench is P, ≦P <
If it is a Pi, one compressor should be unloaded.
), wait for its effect for a period of time t sec.
#Show), the following actions are configured so that all lines are returned.

On the other hand, if the pressure has decreased as a result of the pressure determination (see i), the a degree of low pressure 1 is PI <
If P≦P2, all the compressors that were unloaded last are fully loaded (see k). 1, the path through j, that is, the operation when the degree of pressure drop is P≦P1, is a special part of the present invention, and all compressors in the unload operation are fully loaded to cope with the pressure drop. It is supposed to be done. After that, at the specified time...Jt'sec
Then, start the compressors one by one (see m), and repeat these operations.

In addition, in the linked operation, if the unloading time has not elapsed, the operation in step c is omitted and the pressure determination shown in step d is performed. For example, a long-term pressure increase (Ps≦P
<P4), g→h-+ci→e-+g-
+h, unloading is performed every effect waiting time in h, and cffi is exceeded only when the unloading time in b becomes too long.

Further, in FIG. 4, the interlocking operation/stop flowchart is omitted for convenience of explanation, and the interlocking operation mentioned above means an operating state controlled by a well-known number control panel.

Figures 5 and 6 are used for the number system '@l device of the present invention/7'
1 shows the sequence circuit that can be used.
r, corresponds to block 2 of restraint.

The circle mark in the figure indicates the drive coil of the relay, and each contact point is indicated by the same symbol. The third compressor C2, C, Fi are each shown as floor 2.3.

The main operations will be explained below according to the sequence diagrams shown in FIGS. 5 and 6.

The starting control '@ is relay 4F of the starting circuit in Figure 6,
51. 54, and while the amputation is energized,
Wires are connected so that the compressor corresponding to the valley is in operation (not shown). That is, relays 4E, 5
Contact S connected in series with 1 and 54. l+S02
+ Sog is temporarily turned on by a starting program (not shown), and when relays 4E and 51゜54 are energized, they are self-held by their own contacts 4Ea, , 5] and a2゜54a2, and the valley condenser is It will be started.

1, the actual stop is determined by de-energizing these relays 4E and 51.54.

Other operations will be explained in comparison with the flowchart of FIG. 4. Judgment (detection) of pressure at points a, e, and i in Fig. 4 is performed using the pressure switch P shown in Fig. 2.
The relays 81 to 84 are operated by S, ~PS, and in FIG.
Only the contacts related to the relay 81 that detects ≦Rk are shown. Next, the operations g and h in FIG. 4, that is, the execution of unloading, are performed by the timer reset circuit, unload function confirmation circuit, unload effect waiting time setting circuit, and unload effect waiting time setting circuit shown in FIG.
This is performed by the unload execution circuit. In addition,
The stetbink signal generation circuit and the unload order determining circuit select the unload tossable compressor, and the detailed operation thereof will be described later. It's 1.
The operation j in FIG. 4, which is a characteristic part of the present invention, is performed by the abnormal pressure drop detection circuit shown in FIG. 5 (a).

On the other hand, with regard to stopping, the operations indicated by CX in Figure 4 are as follows
Diagram shows four circuits that can be stopped, timer reset circuit,
This is carried out in the cooling time waiting circuit, the stopping process, and the stepping signal generating circuit and the stopping order determining circuit select the compressor to be stopped next.

The operation of the present invention will be explained in further detail below.

2 in FIG. 5, 1 interlock operation is started, and the first compressor C1 to the second compressor C1. Third compressor 02. Let's consider a case where the engine starts with C and becomes fully traversed.

In this state, the pressure P gradually rises, and the pressure P≦P
< When relay 84 is energized at P4, relay B8 is energized by the current flowing through the contact of stepping I) V-sp, so contact B8a2-X+3b2→81 of the unload execution circuit Xb, -+XI
Since the electric current ηt flows to 2 and relay X12 performs self-holding, Xl2a2 →3(il)3-+ 84a, -+
4F, and the first compressor C8 is unloaded.

In other words, the unload execution circuit is divided into sections corresponding to each compressor (in this example, 3 right and 1 sections), and by energizing relays 4F, 52, and 55, unloading of the corresponding compressor is performed. It is about to be done.

Subsequently, after the first compressor C4 is unloaded, the timer TC of the unload effect waiting time setting circuit is activated.
When the time t sec set in 8 has elapsed, contact TC8
a2 turns on, relay A of the stepping signal generation circuit
0 or energized, contact A. a.

is turned on, and stepping relay 5PItdl step advance relay B is energized. In this samurai history, pressure P or P3
If ≦p<P4, the relay 52 of the unloading execution circuit is activated in the same manner as described above. When the time tsee set by the timer Tag has elapsed, the stepping relay SP+ advances by one step, and the relay BA is energized to the position 3, as described in section 8j.

In this state, when the pressure P becomes P3≦p<p, the relay 55 of the unload execution circuit is energized, and the third
When compressor C3 is also unloaded, the amount of air consumption increases rapidly and the pressure P becomes P≦P, relay 8 becomes FJJ magnetized, and contact 81 of the abnormal pressure drop detection circuit
When a1 is turned on, a current flows to 81a, -+81X, and relay 81X is energized. This* meco contact A
5lxb, , 5txbt, 5lxb, are OF
F, relay XI2 + Xt2+ X32 is null J
JiJJ becomes magnetic, and its contact point is X+! a2r X211a
2 + X52at k off L/4 F
The self-holding of +52 and 55 is completely released, and the compressors C1, C2, and C3, which were in unloading mode, are now in full-rotation mode.

Also, when compressors C+ and Ct are unloaded and compressor C3 is also unloaded, the timer is set.
At the setting time t of l'c6), the stepping relay SP+ becomes 16- in the 3 digit as described above, and relay BA'tlh)J6H is activated, and the compressor that performs unload and full load switching capacity control is set to C3. It becomes. At this time, since the stepping relay SP of the stop order determining circuit shown in FIG. 6 is in the position C3, the relay 8A is energized and its contact 8Aag (FIG. 5) is turned on. In this state, when the pressure P becomes P≦P1 and the relay 81 is turned on, the contact 81a of the abnormal pressure drop detection circuit shown in FIG. 5 is turned on, and the relay 8] and X are fully excited. Therefore, the contact 81Xa+ is turned on, υ, Ab, -+81Xa, -+ TSpa, →B, and the current reaches m, relay B is excited, and its contact, T3a,
, Ba2 is turned on. When contact Ba is turned on, stepping relay SP is energized, and stepping relay SP, 'i
1 step advances to position 1, and relay B8 is energized and its contacts B 8 a21 B 8 as k are turned on. As a result, the current increases as B8a3→Ja,→A, and the current increases to +51ttL. Relay A is energized, nl and its contact Ab+2 is turned off, and relay B is de-energized.

Since relay B has a circuit configuration that repeats on and off depending on the set time tNsee of timer TSp,
The contact 13a is turned on and off every sec, and the stepping relay SP and 'tl step are advanced. This causes contacts B8a3, B9a3 . BAa.

are turned on sequentially, and contacts 88a3.89a3.8Aa3 of relays 88.89, 8A of stepping relay SPz
When the contact m#eL in series with the on contact turns on, relay A' is energized, and that contact A
b+ k is turned off and relay B is energized and timer TS is activated.
p) m la k N divided stepping relay SP1
Stop progress. Therefore, when stepping relay SP+ is in position 1 or 3 as described above, stepping relay SP+ stops at position 1, and contact B8a2
The compressor that performs capacity control by turning on is the compressor C7 that is unloaded first.

As described above, in the number control device of the present invention, when the amount of air consumption decreases, the compressors are unloaded at short intervals, and after a certain period of continuous unloading has elapsed, the compressors are unloaded one by one. In the unit control system that stops the compressors, when a sudden pressure drop is detected due to a sudden increase in the amount of air consumed after the unloading operation has been completed, the unloading operation is stopped at full load. With:
The capacity control unit was assigned to the first compressor to be unloaded among the unload operating units, so
Even if the amount of air consumption increases rapidly, it is possible to recover the low pressure T of 7 in a short time, and the ability to follow the number of compressors in operation is improved even for loads where the amount of air consumption changes significantly. There is an opening point. The reason why the capacity control unit was the first compressor to be unloaded is that the first compressor to be unloaded in the continuous rotation machine is the compressor that will stop when the next pressure rises (P, ≦P<P4). Therefore, it is necessary to perform an unload operation to cool down the compressor body and motor before stopping the compressor. Furthermore, since the capacity control machine repeats unloading and full loading, it tends to be overworked, but in the present invention, the capacity control machine is assigned to the machine that first unloads during the unloading transition. The compressor that is unloaded for the first time recovers more quickly than other compressors, which has the effect of reducing the burden on the motor and compressor itself.

Although the sequence circuit is shown and explained in FIGS. 5 and 6 as an example of the circuit for achieving the operation in the above-mentioned period, it is not necessarily limited to this circuit, and the valley pressure switch The output kP) is added to a so-called microcomputer with a preset program installed, and each combination can be operated smoothly using the output of this microcomputer, which is comparable to IL.
In this case as well, an effect similar to that of 1cI can be obtained.

[Brief explanation of the drawing]

Eko shows one embodiment of the number control device according to the present invention, and FIG. 1 is an explanatory diagram showing installation equipment for compressors;
Fig. 2 (a) is an explanatory diagram showing the flashing connection between the pressure cassuitte and the relay used in the invention, Fig. An explanatory diagram showing the order of starting and stopping, Fig. 4 is a flowchart showing the operation of the present invention, Fig. 5 is an example of a sequence circuit for unloading each compressor, and Fig. 6 is a circuit for stopping the valley compressor. This is an example. C4 to C3...1st to 3rd compressor percentage correction applicant Hokuetsu Kogyo Co., Ltd. JP-A-59-49381 (7)

Claims (1)

[Claims] When the amount of air consumption decreases, the compressor is unloaded for a certain period of time, and after one hour of unloading operation, the compressor is stopped one by one. After the load changeover occurred, the amount of air consumed increased sharply and a sudden pressure drop was detected, so the unloading machine was set to full load, and the machine in charge of quantity control was changed to the unloading machine. This is a number control device that allows the first compressor to be unloaded to take charge.