JPS63283842A - Liquid circulating device - Google Patents

Abstract

PURPOSE:To enable fine regulation of setting temperature, in a device for circulating liquid such as lubricant for various testing devices, by continuously varying the heating capacity of a heater through an electronic controller based on signals fed from temperature detectors and a flow meter. CONSTITUTION:When a pump 4 in a liquid circulating device is operated to circulate liquid 3 in a tank 3 through a circulation conduit 2 with predetermined speed, a heater 5 is operated based on a command fed from an electronic controller 9 if the temperature of the circulating liquid detected through a temperature detector 7a is lower than a predetermined level so as to increase the temperature of the circulating liquid 3 to predetermined level. Temperatures at various points are detected through other temperature detectors 7b, 7d while flow is detected through a flow meter 6, and detected values are provided to an electronic controller 9. Consequently, the heater 10 is operated with optimal heating capacity for a predetermined time based on a control signal calculated from the detected values so as to heat the circulating liquid 3 quickly and effectively to a predetermined temperature and feed the circulating liquid to target machines 8a, 8b.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid circulation device used in equipment such as molds and machine tools that require circulation of oil at a constant temperature.

Conventional technology It has been widely known that oil and other liquids are circulated and supplied to equipment such as molds, machine tools, and various testing equipment for purposes such as lubrication and heat retention. It has a configuration in which a circulation pump for circulating the circulating fluid, a heater for heating the circulating fluid, and a cooler for cooling the circulating fluid are installed respectively in the circulation pipe connected between the A liquid circulation device is used.

Problems to be Solved by the Invention However, the heater installed in the conventional liquid circulation device uses a heat-sensitive element switch such as a thermostat installed inside the tank, which generally makes it difficult to maintain a constant temperature distribution. It is controlled intermittently. Therefore, it is impossible to control the temperature within a minute range, and the effects of atmospheric temperature, length of the circulation pipe, and flow rate of the circulating fluid on the circulating fluid temperature are not taken into account, so the temperature cannot be accurately set. Not only is it difficult to adjust, but the temperature often rises above a predetermined temperature, requiring a cooler.

The present invention has been made to solve these problems, and provides an economically superior liquid circulation device that allows temperature control to be performed reliably and within a fine range.

Means for Solving the Problems The liquid circulation device of the present invention is a liquid circulation device in which a circulation pump and a heater for heating the circulating fluid are installed in a circulation pipe connected between a tank and a target device. In,
A flowmeter and a temperature sensor are installed in the circulation pipe, and the heating capacity of the heater is substantially disabled so as to heat the circulating fluid to a predetermined humidity based on the signals from the flowmeter and temperature sensor. It is characterized by being equipped with an electronic controller that changes in stages.

Based on the signals from the flowmeter and temperature sensor installed in the circulation pipe, the electronic controller controls the heating capacity of the heater almost steplessly so that the circulating fluid in the circulation pipe reaches a predetermined temperature. The temperature is changed to heat the circulating fluid flowing through the circulation pipe, and the circulating fluid at a predetermined temperature is sent to the target device.

Example Next, embodiments of the present invention will be described based on the drawings.

The figure shows a block diagram of an embodiment of the present invention, in which a circulation pipe 2 is connected to a tank 1, and a circulating fluid 3 contained in the tank 1 is connected to the circulation pipe 2, for example. A circulation pump 4 that transports the fluid in the six directions shown in the figure, an electric heater 5 that heats the circulating fluid 3 in the circulation pipe 2, and a flow rate that detects the flow rate of the circulating fluid 3 in the circulation pipe 2. A total of 6 are installed in order along the transport direction of the circulating fluid.

A target device 8a or 8b such as a mold or a processing machine is installed either between the flow meter 6 and the tank 1 in the circulation pipe 2 or between the circulation pump 4 and the heater 5.

Further, a circulation pipe 2 is provided between the flow meter 6 and the heater 5.
A temperature sensor 7a that detects the temperature of the circulating fluid 3 contained in the tank 1, a humidity sensor 7b that detects the temperature of the circulating fluid 3 contained in the tank 1, and a temperature sensor that detects the ambient temperature of the target device 8a or 8b. 7c and 7d are installed respectively.

These temperature sensors 7a to 7d are, for example, thermistors,
They are formed by temperature-sensitive elements such as semiconductor diode sensors, and are each connected to an electronic controller 9. This electronic controller 9 is connected to the heater 5 and is mainly constituted by a microcomputer, and based on electrical signals continuously sent from each temperature sensor 7a to 7d and flow meter 6, the target device 8a or 8b is Calculate the amount of heating required to send the circulating fluid 3 at a predetermined temperature to the heater 5.
It functions to send a predetermined drive signal to the temperature sensor 7a to 7d and a temperature control circuit that calculates a predetermined amount of heating based on the electrical signals sent from the flowmeter 8, and a temperature control circuit for calculating the predetermined heating amount. For example, the switching element includes a switching element such as a thyristor for supplying a predetermined current to the heater 5 based on the timing, and a sequence control circuit for sequentially applying a drive signal to the switching element as time passes.

In addition, 10 is a cooler installed in the circulation pipe 2, which quickly cools the circulating fluid at the end of work to cool the target equipment and prevent oxidation when the circulating fluid is oil. This is installed especially when high-temperature circulating fluid is required, and does not necessarily need to be installed.

When the circulation pump 4 of the liquid circulation system configured as described above is operated to circulate the circulating fluid 3 in the tank 1 through the circulation pipe 3 at a predetermined speed, the temperature of the circulating fluid detected by the temperature sensor is When the temperature is lower than the predetermined temperature, the heater 5 is activated by a command from the electronic controller 9 to quickly raise the temperature of the circulating fluid 3 to the predetermined temperature. In addition, the temperature at each location is detected by the other temperature detectors 7b to 7d, and the flow rate is detected by the flowmeter 6, and these are input to the electronic controller 9, so the control calculated based on these is inputted to the electronic controller 9. In response to the signal, the heater 10 operates for a predetermined period of time with optimal heating capacity, allowing the circulating fluid 3 to rise to a predetermined temperature quickly and without waste, and supplying the circulating fluid 3 at a predetermined temperature to the target device 8a or 8b. can do.

In addition, in this embodiment, the temperature of the circulating fluid can be adjusted continuously by controlling the heating current almost steplessly with the heater 5 constantly operating, and the temperature of the circulating fluid 3 can be adjusted easily and easily. It is possible to reliably maintain a predetermined temperature with extremely high precision.

In this embodiment, the temperature detectors 1a to 1d are arranged at four locations in order to control the heater 5 with high precision, but it is not necessary to provide all of them. For example, only the temperature detector 7a or 7a and 7b, and even 7a and 7b and 7
As shown in C, various selections and placements can be made depending on the type of target equipment used, the required temperature of the circulating fluid, the location where the target equipment is used, etc. In any case, the circulating fluid can be adjusted with sufficient accuracy. It is possible to adjust the temperature of the

Effects of the Invention As described above, the present invention achieves optimum heating by almost steplessly changing the heating capacity of the heater using an electronic controller based on signals from a temperature sensor placed in the circulation pipe and a flow meter. This configuration enables fine adjustment of the set temperature and allows oil to be circulated at an accurate temperature at all times, and the heater can be continuously controlled with low power, resulting in low power consumption and economical performance. It has many advantages, such as being

[Brief explanation of the drawing]

The figure shows a block diagram of an embodiment of the invention. 1...Tank, 2...Circulation pipe line, 3...Circulating fluid,
4... Circulation pump, 5... Heater 1.6... Flow meter, 7a, 7b, 7c, 7d... Temperature detector, 8a
8b--Target device, 9--Electronic controller.

Claims (1)

[Claims] In a liquid circulation device in which a circulation pump and a heater for heating the circulating fluid are installed in a circulation pipe connected between a tank and a target device, a flow meter and a temperature detector are installed in the circulation pipe. It is also characterized by being equipped with an electronic controller that changes the heating capacity of the heater almost steplessly so as to heat the circulating fluid to a predetermined temperature based on the signals from the flowmeter and the temperature sensor. liquid circulation device.