JPH02102013A - Water supply device of hydrated fire retardant hydraulic oil and injection molding machine equipping water supply device - Google Patents

Abstract

PURPOSE:To complete regulation of prescribed water content ratio in a comparatively short time by previously and automatically weighing make-up water necessary for such amount that the water content of hydrated hydraulic oil is regulated to prescribed value and replenishing this make-up water. CONSTITUTION:Water content of hydrated hydraulic oil 2 is detected with a water content detector 4 and an electric signal thereof is amplified with an amplifier 15 and transferred to a controller. This water content is compared with necessary water supply setting value preset in a water content setter in this controller. When water content of hydrated hydraulic oil 2 is the necessary water supply setting value or below, the signal output from he controller excites an electromagnet via an amplifier 18 to open a solenoid valve 7 and water is supplied to a water supply tank 3 via a water supply pipe 8. When necessary amount of make-up water is housed in the water supply tank 3, a detection signal output from a water supply amount detector 10 is transferred to the controller. The signal inputted to the solenoid valve 7 from the controller is cut to close the valve 7 and water supply is completed. The signal output from the controller excites the electromagnet of a solenoid valve 6 via an amplifier 17 and the solenoid valve 6 is opened and thereby the make-up water housed at once is replenished to a storage tank 1.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a water replenishment device for water-containing flame-retardant hydraulic oil and an injection molding machine equipped with the water-replenishing device, and more particularly, to The present invention relates to a water replenishment device for a hydrous flame-retardant hydraulic oil that can automatically replenish the amount of water lost due to water replenishment, etc., and an injection molding machine equipped with the water replenishment device.

(Prior technology) Flame-retardant hydraulic oil is commonly used in hydraulic equipment for machine tools, injection molding machines, etc. due to automation of manufacturing processes, disaster prevention due to unmanned manufacturing, and fire regulations. has been done.

Such flame-retardant hydraulic fluids include water-containing flame-retardant hydraulic fluids (hereinafter sometimes referred to as water-containing hydraulic fluids), which are obtained by adding a certain amount or more of water to mineral oil, etc., so that the flash point has virtually disappeared. It is used.

Note that the water-containing hydraulic oil contains a water solubilizer and additives that impart characteristics as a hydraulic oil.

In such a water-containing hydraulic oil, flame retardancy disappears when the water evaporates and reaches a flash point.

Therefore, in order to maintain the flame retardancy of water-containing hydraulic oil, it is necessary to replenish the water lost through evaporation, etc., and the water content in the hydraulic oil must be constantly monitored and the necessary amount of water replenished. is necessary.

As a water replenishment device that can automatically perform such water replenishment operations, Japanese Patent Application Laid-open No. 59-143936 discloses a system that automatically detects changes in water content from changes in the specific gravity of water-containing hydraulic oil, and calculates the water content in the hydraulic oil. An automatic water refilling device has been proposed that directly supplies water to a storage tank when the water content falls below a predetermined value until the water content reaches a predetermined value.

(Problems to be Solved by the Invention) According to the water replenishment device disclosed in the above-mentioned Japanese Patent Application Publication No. 2003-120000, monitoring of the water content in the water-containing hydraulic oil, calculation of the amount of water replenishment, and operation of water replenishment can be significantly reduced. This greatly reduces operational and management hassles.

However, in the water replenishment device, water is directly replenished from the water source to the storage tank until the water content in the water-containing hydraulic oil, that is, the specific gravity reaches a certain value, without measuring the required amount of water in advance. Due to the time delay until the oil and the supplied water are evenly mixed, excessive water may be supplied in some areas and the properties of the hydraulic oil may be impaired, or conversely, the amount of supplied water may be insufficient in some areas. In some cases, the water content becomes insufficient and cannot be adjusted to a predetermined moisture content.

Then, when such hydraulic oil that has not been adjusted to a predetermined water content is supplied to a hydraulic device such as an injection molding machine whose conditions are set such that the hydraulic oil has been adjusted to a predetermined water content, the following is obtained. The molded product may become defective or damage the hydraulic system.

In order to solve the problem caused by the time delay until the hydraulic oil and make-up water are evenly mixed, a timer or the like is installed to replenish the make-up water in parts. After replenishing, the problem of inadequate adjustment due to the time delay until uniform mixing was resolved, but
It takes an extremely long time to complete the adjustment, and during that time the operation of the injection molding machine, etc. must be stopped, and this method cannot be adopted industrially.

Therefore, an object of the present invention is to provide a hydrous N flammability system that can adjust the moisture content to a predetermined level even if there is a time delay until homogeneous mixing of hydraulic oil and make-up water, and that can complete the adjustment in a relatively short time. An object of the present invention is to provide a hydraulic oil refilling device and an injection molding machine equipped with the refilling device.

(Means for Solving the Problems) The problems of the water-containing hydraulic oil water replenishment device proposed in the above-mentioned Japanese Patent Application Publication No. 2003-11002 and the problems of the injection molding machine equipped with the water replenishment device can be solved by the present invention as described below. This problem can be solved by a water replenishment device having the above structure and an injection molding machine equipped with the water replenishment device.

That is, the present invention provides a storage tank for storing a flame-retardant hydraulic oil for operating a hydraulic system consisting of water-soluble or water-dispersible oils and water, and a water replenishment tank connected to the storage tank.
A detector that detects the water content in hydraulic oil, a refill valve installed in the refill waterway that refills the refill tank with water, and a supply pulp installed in the refill water supply path between the refill tank and the storage tank. a comparison means for comparing the water content of the water-containing hydraulic oil detected by the detector with a water replenishment required set value; a water replenishment detection means for detecting the amount of makeup water to be refilled in the water refill tank; and a water content compared by the comparison means. When the water content of the hydraulic oil falls below the set value, the water replenishment valve is opened, and when the amount of replenishment water detected by the replenishment water amount detection means reaches the required amount of replenishment water, the replenishment valve is closed and the supply pulp is turned off. The water replenishment device for water-containing flame-retardant hydraulic oil is characterized by comprising a water replenishment valve that is opened, and a control means for controlling supply pulp.

In the water replenishment device of the present invention, the moisture content detector detects changes in the specific gravity, conductivity, dielectric constant, or impedance of the hydraulic oil, and/or detects changes in the temperature sensor provided in the storage tank. It is possible to accurately detect the moisture content of the water-containing hydraulic oil, which is activated when the temperature of the hydraulic oil reaches a predetermined temperature.

In addition, the provision of a throttle section in the replenishment water supply path between the replenishment tank and the storage tank and/or the provision of a heating means in the replenishment tank can reduce the temperature of the hydraulic oil in the storage tank during refilling. This is preferable because it does not cause a significant decrease.

Furthermore, in the injection molding machine of the present invention, a mixing circuit for the hydraulic oil and make-up water that bypasses the hydraulic system is provided between the discharge port of the hydraulic oil supply pump and the storage tank. Mixing with makeup water can be done quickly.

(Function) According to the water replenishment device of the present invention, the water necessary for the water content of the hydrous hydraulic oil to reach a predetermined value is automatically measured and replenished in advance, so there is a time delay until a uniform mixing state is achieved. There is no excess or shortage of make-up water due to such factors, and even when refilling in parts, there is no need to hold water until uniformly mixed each time, so adjustment can be completed in a short time.

In addition, in the injection molding machine of the present invention equipped with such a replenishment device, it is possible to prevent an increase in the number of defective molded products or damage to the equipment caused by an excess or deficiency of replenishment water in the hydraulic oil. It is also possible to prevent a decline in the operating rate.

(Example) The present invention will be explained in more detail using figures.

FIG. 1 shows a route map showing one embodiment of the water replenishment system of the present invention.

Water-containing hydraulic oil 2 is stored in the storage tank 1.
is supplied to a hydraulic system (not shown) via a suction filter 11 and a suction pipe 12 by a supply pump (not shown), and return oil is returned to the storage tank 1 via a return vibe 15.

The hydraulic oil returned to the storage tank 1 is prevented from flowing rapidly by the two baffles 13, air bubbles etc. entrapped in the hydraulic oil are removed, and then supplied to the hydraulic system again.

The storage tank 1 is provided with a water content detector 4 for detecting the water content of the water-containing hydraulic oil 2 and an agitator 14.

The water content detector 4 can detect the water content by detecting changes in the specific gravity, conductivity, permittivity, or impedance of the water-containing hydraulic oil.

Here, examples of the specific gravity measurement method include a method in which a floating weight is placed in the standard oil and the used oil and the specific gravity is measured using a balance system, or a method using a density specific gravity needle using a natural frequency measurement method.

In addition, the conductivity measurement method measures the electrical conductivity of the hydraulic oil between two electrode plates, and the dielectric constant measurement method involves propagating a microfluid in the hydraulic oil and measuring the degree of attenuation. Examples of impedance measurement methods include a method in which impedance is measured by passing a current through a coil in water-containing hydraulic oil.

However, the water refilling device according to this embodiment is often installed integrally with or very close to a hydraulic device, and vibrations from the hydraulic device or the like are transmitted to the water content detector 4.

For this reason, the moisture content detector 4 that employs the specific gravity measurement method tends to cause detection failures due to shaking of the hydraulic oil and weight due to vibration, and requires anti-vibration measures.

In this respect, the conductivity measurement method, dielectric constant measurement method, or impedance measurement method is preferable since it is not necessary to take such anti-vibration measures.

Furthermore, since all of these measurement methods are easily affected by the temperature of the hydraulic oil, a temperature sensor is installed in the storage tank 1, and the water content detector 4 is activated when the water-containing hydraulic oil 2 reaches a predetermined temperature. It is necessary to measure the moisture content accurately.

A refilling water tank 3 is connected to the storage tank 1 via a refilling water supply path (refilling water supply pipe) 9, and a refilling water amount detector 10 is connected to the refilling water tank 3 as a refilling water detection means for detecting the amount of replenishing water 5. is provided.

The water replenishment amount detector 10 is set to detect, for example, when the water level reaches a predetermined height using an electrode and a predetermined amount of water is refilled in the water replenishment tank 3 .

The capacity of the water replenishment tank is approximately 1 of the total capacity of the storage tank.
It is preferably about 0%.

A solenoid valve 7 as a water replenishment valve is provided in a replenishment waterway (refill pipe) 8 that supplies water to the refill tank 3 .

Further, a solenoid valve 6 as a supply valve is interposed in a replenishment water supply pipe 9 that connects the replenishment tank 3 and the storage tank 1.

Each of the above-mentioned detectors, solenoid valves, etc. are connected to the controller directly or via an amplifier.

That is, the signal from the moisture content detector 4 is transmitted to the controller via the amplifier 15, and in the controller, the required water replenishment setting value set in the moisture content setting device and the moisture content of the hydrous hydraulic oil 2 in the storage tank 1 are determined. are compared.

In this manner, the controller has a comparison mechanism that compares the water content of the water-containing hydraulic oil 2 with the water replenishment required set value.

The outputs from such controllers are sent to amplifiers 16, 17 .
It is transmitted to the stirrer 14 , the solenoid valve 6 , and the solenoid valve 7 via the solenoid valve 18 .

Therefore, the controller also serves as a control mechanism for controlling the solenoid valve 7 as the water replenishment valve and the solenoid valve 9 as the supply valve.

Next, the operation of this water refilling device will be explained using FIG. 2.

FIG. 2 is a flowchart showing the procedure of the controller shown in FIG.

First, the water content of the water-containing hydraulic oil 2 is detected by the water content detector 4, and its electrical signal is amplified by the amplifier 15 and transmitted to the controller (step 101).

The water content of the water-containing hydraulic oil 2 is compared in the controller with the water replenishment necessary set value set in the water content setting device (step 102).

When the water content of the water-containing hydraulic oil 2 is less than the water refilling required set value, a signal from the controller excites the electromagnet of the solenoid valve 7 via the amplifier 18 to open the solenoid valve 7, and the water refill pipe 8 is opened.
Water is supplied to the supplementary water tank 3 via (step 10)
3). At this time, the solenoid valve 6 provided in the water replenishment pipe 9 connecting the water refill tank 3 and the storage tank 1 is kept closed.

A refill water amount detector 10 provided in the refill tank 3
The detection end (for example, an electrode) detects that when the water content of the water-containing hydraulic oil 2 reaches the water content set in the water content setting device, the amount of water required for replenishment has been stored in the water replenishment tank 3. It is set in advance at a position where it can be detected that the make-up water 5 has reached a predetermined water level and the amount of water necessary for replenishment has been accommodated in the make-up water tank 3. When the required amount of make-up water is stored in the refill tank 3, a detection signal from the refill water amount detector IO is transmitted to the controller (step 104), and the signal from the controller to the solenoid valve 7 is cut off, causing the solenoid valve 7 to close. This completes the supply of water to the supplementary water tank 3 (step 105).

After the solenoid valve 7 is closed, the makeup water 5 once stored in the makeup water tank 3 is supplied with a signal from the controller via the amplifier 17 to excite the electromagnet of the solenoid valve 6 and open the solenoid valve 6. and the storage tank 1 is replenished (step 106).
.

At this time, the agitator 14 is stirred to promote mixing of the water-containing hydraulic oil 2 and makeup water 5.

The agitator 14 is installed at the suction filter 1.
It is preferable to install the oil bubbles at a distance of more than 1, so that air bubbles that are drawn into the hydraulic oil 2 due to stirring can be removed before reaching the suction filter 11.

When the makeup water 5 is being replenished into the storage tank 1 in this way, the physical properties of the hydraulic oil, especially the temperature, change, so it is preferable to stop the operation of the hydraulic system.

The operation of the hydraulic system whose operation has been stopped in this way can be restarted after the makeup water 5 has been fully replenished into the storage tank 1, and the water-containing hydraulic oil 2 has reached a predetermined temperature and has been adjusted to a predetermined water content. Restarting the operation of the hydraulic system after confirming that it is possible to prevent an increase in the number of defective molded products obtained or damage to the hydraulic system.

In order to minimize changes in the physical properties of the hydraulic oil, especially the temperature, and to enable continuous operation of the hydraulic system, a heating means such as a heater is provided in the replenishment tank 3 to raise the temperature of the replenishment water 5 to a predetermined temperature. It is preferable to gradually replenish the storage tank 1 with the makeup water 5 by providing a constriction part in the replenishment water supply pipe 9 and/or to gradually replenish the storage tank 1 with the makeup water 5.

As a heating means for the make-up water 5, since the temperature of return oil from the hydraulic system is high, the make-up water 5 may be heated by passing the return oil through a pipe provided in the make-up water tank 3.

Further, the constricted portion of the supplementary water supply pipe 9 can be replaced by adjusting the opening degree of the solenoid valve 6.

The solenoid valve 5 is operated by a timer (step 107) that operates when the controller issues a signal to open the solenoid valve 6.
) is up and closed (step 1)
08).

The water refilling device of the present invention described above can be used in various hydraulic devices, but for those that require high hydraulic pressure exceeding 200 kg/cni G, the lubricity of the water-containing hydraulic oil may be a problem. Therefore, it is suitable for a hydraulic system of an injection molding machine that uses relatively low pressure hydraulic pressure.

In the water supply system used in the hydraulic system of such an injection molding machine, a hydraulic oil supply pump (not shown) and a storage tank 1 are used.
It is advisable to provide a circuit that bypasses the hydraulic system between the two. By circulating and mixing the hydraulic oil in this bypass circuit by maximizing the discharge amount of the hydraulic oil supply pump, the hydraulic oil 2 and the make-up water 5 can be mixed quickly.

In addition, it goes without saying that the water content setting value set on the water content setting device should be set at a water content that substantially eliminates the flash point of the water-containing hydraulic oil 2, and should be set slightly higher for safety reasons. preferable.

(Effects of the Invention) According to the water refilling device of the present invention, the water content of water-containing hydraulic oil can be automatically and accurately adjusted.

Furthermore, in an injection molding machine in which such a water refilling device is installed in a hydraulic system, the water content of the hydraulic oil can be adjusted accurately in a short time, thereby preventing a decrease in operating efficiency and an increase in the number of defective molded products.

[Brief explanation of the drawing]

FIG. 1 is a route map showing one embodiment of the water replenishment system of the present invention, and FIG. 2 is a flowchart showing the procedure of the controller shown in FIG. 1. In the figure, 1. Storage tank, 2. Water-containing flame-retardant hydraulic oil, 3.
... Refilling water tank, 4... Moisture content detection device, 5...
Make-up water, 6... Supply valve, 7... Refill water valve.

Claims (1)

[Claims] 1. A storage tank for storing a flame-retardant hydraulic oil for operating a hydraulic system, which is made of water-soluble or water-dispersible oils and water, and connected to the storage tank via a supplementary water supply line. A water replenishment tank, a detector that detects the water content in the hydraulic oil, a refill valve installed in the refill waterway that refills the water tank, and a refill water supply path between the refill tank and the storage tank. a supply valve installed in the water supply valve, a comparison means for comparing the water content of the water-containing hydraulic oil detected by the detector with a water replenishment required setting value, and a water replenishment detection means for detecting the amount of makeup water to be refilled in the water replenishment tank; When the water content of the water-containing hydraulic oil compared by the comparison means becomes equal to or less than the set value, the refill valve is opened, and when the amount of replenishment water detected by the replenishment water amount detection means reaches the required refill amount, the refill valve is opened. 1. A rehydration device for water-containing flame-retardant hydraulic oil, comprising a control means for controlling a rehydration valve and a supply valve, which closes the rehydration valve and opens the supply valve. 2. The moisture content detector detects the specific gravity, conductivity, dielectric constant,
2. The rehydration device for hydrous flame-retardant hydraulic oil according to claim 1, which detects a change in impedance or a change in impedance. 3. The moisture content detector according to claim 1 or 2, wherein the moisture content detector is activated when the temperature of the hydraulic oil detected by a temperature sensor provided in the storage tank reaches a predetermined temperature. Replenishment system for flammable hydraulic oil. 4. The rehydration device for water-containing flame-retardant hydraulic oil according to claim 1, wherein a constriction portion is provided in the refill water supply path between the refill tank and the storage tank. 5. Claim 1, wherein the refilling water tank is provided with heating means
A water replenishing device for a water-containing flame-retardant hydraulic oil according to item 1 or 4. 6. An injection molding machine, characterized in that a storage tank for supplying hydraulic oil to a hydraulic system of the injection molding machine is provided with the water refilling device according to claim 1. 7. Between the discharge port of the hydraulic oil supply pump and the storage tank,
7. The injection molding machine according to claim 6, further comprising a mixing circuit for hydraulic oil and make-up water that bypasses the hydraulic system.