JPS6228801A - Automatic alternate operation circuit - Google Patents

Abstract

PURPOSE:To offer an automatic alternate operation circuit to be efficiently operated in spite of a failure of a liquid level detector by applying a pump selecting signal continuously until a selection side pump contactor is opened. CONSTITUTION:A relay 12 holes itself by a pump A contactor closing signal and a relay 13 is excited at the opening of a pump A contactor. When the selection switching relay 13 is excited, a pump B selecting signal 5 is outputted. Although the self-holding of the relay 12 is released by a pump B contactor closing signal 3, the relay 13 continuously outputs the pump B selecting signal 5. When the excitation of the relay 13 is erased at the opening of the pump B contactor, the pump B selecting signal 5 is switched to a pump A selecting signal 4. Thus, a transfer pump circuit to be efficiently operated in spite of a failure of the liquid level detector can be constituted by adding only one relay.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to an automatic alternating operation of a waste liquid transfer pump, and in particular, an automatic alternating operation which is suitable even in response to failure of a liquid level detector, which is a condition for starting and stopping the pump. Regarding the driving circuit.

[Background of the invention]

A conventional automatic alternate operation circuit will be explained with reference to FIGS. 1 and 2. As shown in FIG. 1, the automatic alternate operation circuit of a conventional waste liquid transfer pump is comprised of a generally known self-holding circuit described in Sequence Control System by Minoru Shihyoma (Denkishoin). In other words, when there are A and 82 pumps, the relay 2 is self-held by the pump A contactor close signal 1, and is released from self-hold by the pump B contactor close signal 3.The 7 selection command is as follows. On the other hand, pump A.

B contactor open signals are combined to generate pump A selection signals 4.B and 4.B, respectively. A pump B selection signal 5 is generated.

FIG. 2 shows a startup circuit for two waste liquid transfer pumps A. The pump detects the liquid level of waste liquid accumulating in the tank with a detector, and uses a liquid level high signal 6 and a liquid level bulky signal 7 as a backup. It starts automatically and automatically stops at the low liquid level signal 8 and the low liquid level signal 9 as a backup. usually,
The low liquid level signal 8, which is a stop condition, is set to the self-holding side in order to prevent the pump from being unable to start despite the high liquid level due to failure of the liquid level detector.

Therefore, a low liquid level signal 8 is generated due to a detector failure.

Even with continuous output, the pump can be started, although self-holding cannot be achieved by the auxiliary contact 11 of the pump contactor. However, in the conventional automatic alternating operation circuit, the pump A selection signal 4 disappears immediately after the pump A is started because the relay 2 is energized, so the pump stops immediately after the pump is started.

As a result of the stop, pump B starts, but since pump B also stops immediately after starting, 82 pumps A and 82 start and stop repeatedly. For this reason, there was a drawback that the pump could not rotate and the waste liquid could not be transferred until the pack amplifier was activated due to the high liquid level, even though the waste liquid should normally be transferred at a high liquid level.

[Purpose of the invention]

An object of the present invention is to provide an automatic alternating operation circuit that can operate effectively even when a liquid level detector fails, which is a condition for starting and stopping a pump.

[Summary of the invention]

Conventionally, the pump selection signal disappears after confirming that the selection side pump contactor is closed, but the present invention continuously provides the selection signal until the selection side pump contactor is closed, and the liquid level detector fails. This eliminates the conventional drawback of not being able to transfer waste liquid at the same time.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4. The present invention applies a self-holding circuit in the same way as the conventional one, but as shown in FIG. 3, the disadvantages of the conventional one are solved by adding a selection switching relay 13.

That is, relay 12 is activated by pump A contactor close signal 1.
is self-holding, and relay ]-3 is energized between pump A contactors. By energizing the selection switching relay 13,
Pump B selection signal 5 is output. The self-holding of the relay 12 is released by the pump B contactor close signal 3, but while the pump B contactor close signal 3 is present, the selection switching relay 13 is
Continue outputting pump B selection signal 5. When the relay 13 is no longer energized between the pump B contactors, the signal is switched to the pump A selection signal 4.

FIG. 4 shows the application of the present invention to waste liquid transfer pump A, and even if the liquid level low signal 8 is continuously output, the pump A selection signal is continuously given, so the waste liquid transfer conditions are met. While the liquid level high signal 6 is present, the pump continues to transfer and the liquid level does not become bulky.

Although this embodiment has been explained using an electromagnetic relay, it goes without saying that it can be easily applied to logic and sequence controllers using semiconductor elements.

〔Effect of the invention〕

According to the present invention, with the minimum addition of one relay, it is possible to configure a waste liquid transfer pump circuit that can operate effectively even in the case of failure of the liquid level detector, which is a condition for starting and stopping the waste liquid transfer pump. We can expect a system with improved reliability.

[Brief explanation of the drawing]

Figure 1 is a conventional automatic alternate operation circuit diagram, Figure 2 is a waste liquid transfer pump A startup circuit diagram to which the conventional automatic alternate operation circuit is applied, Figure 3 is an automatic alternate operation circuit diagram of the present invention, and Figure 4 is A starting circuit diagram of the waste liquid transfer pump A to which the present invention is applied, FIG. 5 is a time chart of a conventional automatic alternate operation circuit, and FIG. 6 is a time chart of the automatic alternate operation circuit of the present invention. 1... Pump A contactor close signal, 3... Pump B contactor close repair, 4... Pump A selection signal, 5... Pump B selection signal, 6... Liquid level high signal, 7...Liquid level bulk signal, 8...Liquid level low signal, 9...Liquid level low/low signal, 10
... Pump contactor, 11... Auxiliary contact of pump contactor, ], 3... Selection switching relay.

Claims (1)

[Claims] In an automatic alternating operation circuit that starts one device when a starting condition is met for one or two controlled devices, stops when the condition no longer exists, and starts the other device when the starting condition is met again. , when one device has definitely stopped, the selection command given to the other device is not turned off when the selection device confirms its startup, but until it is confirmed that the startup condition for the selection device has disappeared and it has stopped. An automatic alternating operation circuit characterized by continuous feeding.