JPS5874883A - Apparatus for controlling the number of compressors to be operated - Google Patents

Abstract

PURPOSE:To prevent abrupt drop of pressure when consumption of air is increased abnormally, by presetting a lower-limit value of abnormal pressure, and starting at least one compressor immediately without waiting time in case that pressure is dropped to a level lower than the lower-limit value of abnormal pressure. CONSTITUTION:It is assumed that pressure is raised after starting of sequential operation of compressors and that a plurality of compressors C1-C3 are unloaded. When a prescribed unloading time is passed in the above state[refer to (b) in the drawing], operation of the compressor that is unloaded first is stopped (c). Here, the pressure of air discharged from the compressors C1-C3 into a concentrated tank 2 is detected, and in case that it is lower than a prescribed lower-limit value of abnormal pressure, the compressor that is stopped first during the operation awaiting time is started immediately without awaiting time by means of pressure switches PS1-PS4 attached to the tank 2. With such an arrangement, it is enabled to prevent abnormal drop of pressure even if consumption of air is increased abruptly.

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 as necessary to stably discharge compressed air at a desired pressure, and this is utilized.

In this case, when operating a group of multiple compressors,
For example, if the amount of air used suddenly increases or decreases, pressure fluctuations will occur.

In such cases, it is necessary to operate each compressor appropriately according to pressure fluctuations.

However, if the pressure decreases when multiple Fi compressors are operated appropriately in this type of conventional unit control system, it is difficult to determine whether the pressure decrease is temporary or a continuous pressure decrease. In order to make a determination, the compressor should not be restarted for a certain period of time (effect waiting time) after the pressure has decreased, and only one compressor should be started after an hour has passed. Unfortunately, if the amount of air consumed suddenly increases, there is a risk that the pressure will drop abnormally.The present invention was proposed in view of the above points, and the amount of air used increases abnormally. The object of the present invention is to provide a device for controlling the number of compressors that completely prevents a sudden drop in pressure even in such a case.

In other words, in the present invention, in the compressor number control device, in order to prevent the pressure from decreasing abnormally when the amount of air used suddenly increases, a pressure abnormality 1 limit value is set, and the pressure abnormality lower limit value is set higher than the pressure abnormality lower limit value. The invention is characterized in that in the event of a pressure drop, at least one compressor is started immediately without any waiting time, thereby achieving the above object.

Hereinafter, the present invention will be explained along with the drawings.

FIG. 1 is an explanatory diagram showing the entirety of the present invention, and C1 to C1 in FIG.
Csu first to third compressors, these compressors C3 to C
Collecting pipes 1 are connected to the discharge sides of the pipes 3 and 3 to form a single discharge system, and the compressed air from each compressor C1 to C1 is once sent into the collection tank 2 and then transferred to the pipes 3 and 3. It is designed to be discharged to the outside via the milled pulp 4. The collecting tank 2 is provided with pressure switches PS, -PSm which detect the pressure sound inside the line and turn on and off when a predetermined pressure value is reached, thereby operating a relay to be described later. These pressure switches PS, ~PS4
Let the set pressures of P and ~P be respectively, then each pressure switch P
The contacts of Sl to PS4 turn on when the set pressure is exceeded, and the relationship between each set pressure is defined as R<R< Ps < P4, and %Pl is the abnormal pressure drop% and P! means pressure drop, pmm positive pressure rise, Pa company positive pressure abnormal rise. Note that in the above, the number of compressors is not limited to only three.

Figure 2 (a) shows the connections between each pressure switch and relay.
- Show. Each pressure switch PS, - is connected to the relays 81 to 84 through the contact signal line conversion circuit 5 to be energized, and in this case, each of the relays 81 to 84
q It is constructed so that it is excited when the pressure in the collecting tank 2 is in the pressure state P as shown below.

P≧P4...Relay excitation P, N P≧P1...Bending relay excitation P! ≧p > p, ・Relay blade excitation P≦P1...
. . . Excitation of the relay 81 The above relationship is illustrated in an easy-to-understand diagram as shown in FIG. 2 (b).

FIG. 3 shows the starting or stopping order of each of the first to first compressors C0 to c1, and shows the starting order C in the present invention.
I-+C! →C1→C1..., and the stopping order is the face that started, that is, C3→c! -4c,
It is configured to stop in the order of →c1... Therefore, during the interlock operation, the first compressor C8 is operated and the second compressor C8 is operated. Third compressor Ct, C
In a situation where the compressor m is stopped, the second compressor Ct is the one that stopped first, and the next starter is the second compressor Ct.

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 among the unloading machines is stopped (C
reference). and.

The pressure is judged (see d), and if the pressure has decreased, Fi (see C), and as shown by the solid line thread path, the degree of pressure drop is P (if R, then relay 81t-excitation'ja The first compressor that stopped during a stopped machine can be immediately started in an emergency without waiting for the effect to take effect (see 1).

The degree of pressure drop is PI < PsP.

In this case, the relay 82t should be energized to fully load the unloading machine or, if there is one, the last compressor that was unloaded (see l). Then, start the compressors one by one (see 1), and repeat these operations as appropriate.

In addition, in the linked operation, if there is no unloading machine, or if the unloading time has not elapsed even though the unloading machine is present, the operation in C is omitted and the pressure judgment shown in d is performed. It has become.

On the other hand, if the pressure has increased as a result of the pressure judgment, and the degree of pressure increase is P≧P, as shown by the broken line, unload the entire machine to prevent the pressure from increasing abnormally. j), and the degree of pressure increase is P1≦P (P
, then unload one compressor (see l), wait for its effect for a predetermined time t (see m), and thereafter repeat these operations.
In the figure, the i-dynamic operation stop flowchart is omitted for convenience of explanation. In addition, in the above, interlocking operation and Fi.

This refers to an operating state controlled by a well-known number control panel.

Figure #I5 is an example of a sequence circuit used in the present invention to concretely realize the above-mentioned operation.The main operation will be explained below.When the interlock operation start switch (not shown) is turned on, the contact point) (Oal turns on, and relay BO is energized through stepping relay SP.0 This causes current to flow from BOa, → 36b → Ylj, relay Y, 3 is energized, and current flows from YIJ cap → 4E. The flow n relay 4E is self-retaining, and the first compressor Cr (in the figure, the first compressor C1 is simply 1, the second and third compressors Ct
, Cs is shown as waterfalls 2 and 3) starts. However, at this time, the collective tank pressure P is in an abnormally low state, so contacts 81a, , 81al are turned on, and 81b, t
I'm off.

Next, when the pressure gradually increases, the contact 81b turns on, and the relay 81Y self-holds through the contacts 81Ya and 81lz. In addition, when one compressor starts and t1 returns, the timer Tc @ a time expires, Tc7m1 is turned on, and relay AO is energized. The advance relay B1 is energized and the second compressor Ct starts.At the same time, the F-timer Tc is set to the operation of the contact 'fc@a', so after the second compressor C8 starts, t Contact 81a, , the pressure does not increase even after the passage of time.
If both contacts of 82&, do not turn off, turn the third pressure 8C
1 will also start.

As described above, the pressure is adjusted to the specified pressure, that is, Fig. 2 00
) until the region of Px < P < Pg is reached, the compressor C2~
The C8s will be started one by one.

Here, the first compressor C1 is in operation and the second compressor C1 is in operation. Third compression 1
! Let us consider the case where k Cm and Cm are stopped.

When the amount of air used increases rapidly and the pressure decreases rapidly, and the relay 81 shown in Fig. 2 (1) is energized (at the time of abnormal pressure drop), Yl, a, -+81Ya, -+81X
A current flows, turning on contact 81Xa and energizing relay A. Therefore, the stepping relay = SPI advances by one step.

The second compressor C1 starts immediately, and if the pressure does not increase after t, the third compressor C1 starts. In a multi-unit control device that sequentially starts or stops compressors, the discharge pressure from each compressor is sent into a collecting tank, and the detected pressure is used to trigger a pressure switch provided in the collecting tank. If the preset pressure abnormality lower limit value = 9 also decreases, at least one or more compressors are immediately started without waiting for the effect to take effect.
It has the advantage of completely preventing an abnormal drop in pressure even when the amount of air consumption increases rapidly.In addition, in the above explanation, a sequence circuit is shown in FIG. 5 as an example of a circuit for achieving the operating tube. As explained above, the circuit is not necessarily limited to this circuit, and the output of each pressure switch is pre-installed with a predetermined program. It is also possible to do this, and in this case, substantially the same effect can be obtained.

[Brief explanation of drawings]

Is the drawing an example of a control device for one compressor according to the present invention? Figure 1 is an explanatory diagram showing the installation equipment of the compressor, Figure 2 is an explanatory diagram showing the relationship between the pressure switch and relay used in the present invention, and Figure 1 (B) is an explanatory diagram showing the relationship between the pressure switch and the relay used in the present invention. FIG. 3 is an explanatory diagram showing the starting and stopping order of each compressor of the present invention, 41st hill is a flowchart showing the operation of the present invention, and FIG. 5 is an example of a circuit used in the present invention. be. C3~C1...First~third compressor %PS1~
PS6: Pressure switch, 2: Collecting tank Patent applicant Hokuetsu Kogyo Co., Ltd. ) November 27, 1981 Commissioner of the Japan Patent Office Shima 1) Spring Tree 1, Display of the case 1982 Patent Application No. 172350 2, Name of the invention Compressor number control device 3, Person making the amendment Related Patent Applicant Name: Hokuetsu Kogyo Co., Ltd. 4, Agent Address: 7-10-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo 160
No. 3 & ``Detailed Description of the Invention'' in the specification subject to amendment and No. 4 in the attached drawings
Figure 5, Figure 6, Contents of the Amendment As shown in the appendix 1, "increase or decrease" in the additional line of page 1 of the specification.
It increases and decreases.'' 2. "Reference l" on page 6, line 12 of the same book is corrected to "reference l". 3. Change "81X and current" from page 8, line 13 of the same book to "81
4. Correct "detected pressure" in the second line of page 9 of the same book to "detected pressure value."

Claims (1)

[Claims] In a number control device that sequentially starts or stops a plurality of compressors, the discharge pressure of each compressor sent into a collection tank is detected, and the detected pressure value is set in the previous one collection tank. The number of compressors characterized in that when all the valves are turned on and the preset pressure abnormality lower limit value j9 also drops, at least one or more compressors are started immediately without making a sound during the effect waiting time. Control device.