GB2239002A - Coolant system; mixing and dispensing liquids - Google Patents

Abstract

A coolant system for a machine shop in which a drum (12) of coolant concentrate has the concentrate withdrawn therefrom by water under pressure flowing via a venturi mixer valve (18) to fill a sump (14). A pump (30) pressurizes a storage tank (38) and these feed a manifold (39) from which coolant can be fed to each machine via an individual discharge line (44) provided with its own discharge nozzle (46). <IMAGE>

Description

COOLANT SYSTEM The present invention relates a coolant system for a machine shop.

It has been the practice in a machine shop for each machine operator to mix his own coolant/cutting fluid.

Normally a soluble oil is mixed with water in a suitable container, and is then poured into the holding tank of the particular machine tool. While this has been satisfactory with, highly sophisticated machine tools, it is not always possible to ensure that an adequate quantity of correctly mixed coolant is produced in a repeatable manner. As a result of this damage can be done firstly to the workpiece being machined and more importantly to the machine tool itself.

It is now proposed, according to the present invention, to provide a coolant system for a machine shop, said system comprising a probe for insertion into a container of coolant concentrate, a mixing valve for mixing concentrate withdrawn from said container by said probe, at a controlled rate with water to form the desired coolant, a sump connected to said mixing valve to receive the coolant from said mixing valve, a pump having an inlet connected to said sump and an outlet, a pressurized storage tank connected to said pump outlet, to receive coolant therefrom, a plurality of discharge lines connected to said pressurized storage tank and a valved discharge nozzle associated with each discharge line, to control the flow of coolant through each said discharge line.

With such a system it is possible to obtain considerable accuracy of the coolant mix because the mixing is effected at a central location and this can be done in a highly controlled manner. Each machine tool may be provided with its own discharge nozzle and, when it is required to replenish the storage tank of that machine tool, the discharge nozzle associated therewith can be opened to supply a correctly mixed quantity of the coolant. This enables there to be a reliable supply of accurately mixed coolant enabling the equipment to be easily maintained. A large number of machines, for example 12 or more can be supplied from the central coolant supply, which is very easy to use and labour saving.Furthermore, it avoids any skin contact with the coolant by the machine operator and this is particularly important with regard to the operator contacting the concentrated coolant which can have a harmful effect on the skin.

The mixing valve may take a number of different forms but in the preferred simple construction it is in the form of a venturi valve having a mains water supply connected thereto.

Advantageously the sump is provided with a level sensor and said mains water supply includes a solenoid operated valve controlled by said sensor to maintain a desired level of coolant in the sump.

Preferably the pump outlet is connected to the pressurized tank via a three-way connector having a first arm connected to the pump outlet, a second arm connected to the pressurized storage tank and a third arm connected to a main discharge manifold, to which said discharge lines are connected. One of the advantages of the system of the invention is that while the pump can largely supply the nozzles, the pressurized storage tank ensures an adequate supply is always available.

The pressurized storage tank is advantageously resiliently expandable and may include a resiliently expansible rubber bag.

The pump is advantageously of the positive displacement type e.g. a helical gear pump.

In order that the present invention may more readily be understood, the following description is given, merely by way of example, reference being made to the accompanying drawing in which the sole figure is a schematic view of one embodiment of coolant system according to the present invention.

Mounted on the skid 10 is a drum 12 of concentrated coolant/cutting fluid which will usually be of the 45 gallon type, and has associated therewith a drum level sensor 13. Also mounted on the skid 10 is a sump 14 which is conveniently of a 40 gallon size.

Also extending into the drum 12 is a probe 16 which is connected to the suction inlet of a venturi mixer valve 18 which has associated therewith a first pressure gauge 19.

The mains water supply 20 is fed via a stop-cock 22 and an inlet line to a solenoid valve 24 which, when open, feeds water via inlet pipe 25 to the venturi valve 18.

The outlet of the venturi valve 18 is connected to an outlet pipe 26 which leads to the sump 14 and has a vent 28 to atmosphere.

Mounted on or adjacent to the sump 14 is a pump which is preferably of a positive displacement type, e.g. a helical gear pump, having an inlet 32 and an outlet 34. The outlet 34 is connected to a three-way connector 36 having a first arm connected to the pump outlet 34, a second arm connected to a pressurized storage tank 38 and a third arm connected to a discharge manifold 39.

While the pressurized storage tank 38 may take any form, it is advantageously one which is resiliently expandable, for example in the form of a resiliently expandable rubber bag (not shown).

Associated with the three-way connector 36 is a second pressure gauge 40. The manifold 39 has an outlet valve 42 and connected downstream of this are a plurality of discharge lines 44. In the drawing only four such discharge lines are shown but it is envisaged that a far larger number, for example twelve or even more may be provided depending on the number of machine tools within the machine shop. Each discharge line 44 has at its end a discharge nozzle 46 similar to that conventionally employed at a petrol pump used at a filling station.

Electrical mains supply 48 is connected via a main switch 50 to a control panel 52 which supplies power in a controlled manner to the various components as illustrated schematically. One of these lines 53 is connected to a warning light 54 while line 56 is connected to the drum level sensor 13 via a quick release connector 57.

In use, a new drum 12 is positioned on the skid 10 and the probe 16 and the drum level sensor 13 are inserted.

The insertion of the probe 16 is facilitated because the lines 25, 26 are of a flexible hose, e.g. a 19 mm hose.

When the stop-cock 22 is opened and a sump level sensor 58 senses that the sump is not adequately full, the solenoid valve 24 is opened and water flows via inlet pipe 25 to the venturi mixing valve 18. This will cause a controlled amount of coolant concentrate to be withdrawn from the drum 12 so that a correct mix of concentrate and water is supplied to the sump 14. This flow continues until the sump is adequately full. The pump 30 is operated and the mixed coolant is supplied under pressure into the pressurized storage tank 38 and to the manifold 39. When the outlet valve 42 is opened, coolant under pressure is supplied to each of the discharge lines 44.

When a particular machine operator requires more coolant, he simply operates his nozzle 46 to fill up the storage tank associated with his machine tool. When this is done, the warning light 54 will come on effectively to advise other machine operators that they should not, at least at that stage, operate their nozzle 46. The capacity of the pump 30 and of the pressurized storage tank 38 is such as to ensure an adequate flow of coolant to each machine within the workshop.

From time to time, of course, the drum 12 will need to be replaced as indicated by the sensor 13. However, while this replacement is being done, there will be an adequate supply of coolant within the sump 14 and pressurized storage tank 38.

Claims (10)

1. A coolant system for a machine shop, said system comprising a probe for insertion into a container of coolant concentrate, a mixing valve for mixing concentrate withdrawn from said container by said probe, at a controlled rate with water to form the desired coolant, a sump connected to said mixing valve to receive the coolant from said mixing valve, a pump having an inlet connected to said sump and an outlet, a pressurized storage tank connected to said pump outlet, to receive coolant therefrom, a plurality of discharge lines connected to said pressurized storage tank and a valved discharge nozzle associated with each discharge line, to control the flow of coolant through each said discharge line.

2. A system according to claim 1, wherein said mixing valve is a venturi valve having a mains water supply connected thereto.

3. A system according to claim 2, wherein said sump is provided with a level sensor and said mains water supply includes a solenoid operated valve controlled by said sensor to maintain a desired level of coolant in the sump.

4. A system according to any preceding claim, wherein the pump outlet is connected to the pressurized tank via a three-way connector having a first arm connected to the pump outlet, a second arm connected to the pressurized storage tank and a third arm connected to a main discharge manifold, to which said discharge lines are connected.

5. A system according to claim 4, wherein a pressure gauge is connected to said three-way connector.

6. A system according to any preceding claim, wherein the pressurized storage tank is resiliently expansible.

7. A system according to claim 6, wherein the pressurized storage tank includes a resiliently expansible rubber bag.

8. A system according to any preceding claim, wherein said pump is a positive displacement pump.

9. A system according to claim 8, wherein said pump is a helical gear pump.

10. A coolant system for a machine shop substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawing.