The prior art

The invention relates to service equipment for servicing cooling systems in vehicles and comprising an emptying mechanism for emptying coolant possibly admixed with oil and/or a filling mechanism for filling coolant to a closed circuit and having means for sucking out possibly inflammable cool- ants.

Equipment of this type is used for servicing cooling systems, where the coolants are formed by non-inflammable substances, for which reason the requirements of a safety zone in connection with the equipment itself are not necessary.

Where, however, the coolant consists of an inflammable substance, the equipment must satisfy the so-called ATEX Directive, in which rules relating to the use of and equipment for the treatment of inflammable agents involve requirements with respect to the equipment in the form of safety zones.

The object of the invention

It is the object of the invention to provide service equipment for use in con- nection with inflammable media, such as inflammable coolants and mixtures of these with oil, and this is achieved according to the invention by means of equipment having a mechanism which consists of an adapter, which is provided with coupling means in the form of gripping claws for gripping a filling stub, said coupling means being activated by an actuator, and is also provided with ventilation of the area inside the adapter in which inflammable gases may occur. It is ensured in this surprisingly simple manner that the inflammable area, the so-called Zone 2 area, is restricted to the area inside the adapter itself.

This provides the great practical advantage that the area around the adapter is downgraded, i.e. is designated a non-dangerous area.

When, as stated in claim 2, air is sucked out via a channel in the supply hose, the desired ventilation of possible inflammable media in the Zone 2 area may be achieved in a simple manner.

When, as stated in claim 3, the tightness of the system is tested by a pressure test and a subsequent vacuum test, it will be assured that all gaskets and fits are absolutely tight, and thereby that the area around the adapter may be downgraded to a non-inflammable area.

When, as stated in claim 4, the gripping means for the filling stub are constructed as hinged gripping claws, which cooperate with an annular groove in the filling stub, and which are brought into engagement by an axial displacement of an outer bushing with bosses caused by the actuator, a safe and pressure-proof coupling is achieved.

When, as stated in claim 5, the gasket is affected by means of a spring pressure which subjects the gasket to axial pressure, and whose spring is compressed by the pneumatic actuator, a simple and reliable tightness is achieved.

The part of the actuator which opens the non-return valve, is a rod extending at the axis of the pipe, said rod being in firm connection with the pneumatic piston and being adapted to continue the axial movement after the gripping means for the stub have been brought into engagement and the gasket has been subjected to axial pressure, whereby the end of the rod pushes the non-return valve to an open position, said spring unit being compressed additionally by the continued movement of the piston, as stated in claim 6. When the actuator has performed the first operations, its movement continues against the action of the spring, whereby the rod disposed innermost is caused to contact the non-return valve and opens it.

Environmental considerations, too, are to be shown with respect to the re- sidual medium volume which occurs after a filling with an ordinary filling apparatus.

Since, during the filling process, the medium may change its state from liquid to gas, the coupling, as stated in claim 7, is provided with a heating member, said heating member counteracting condensation in the coupling itself, but it is ensured at the same time that the medium enters into a gas phase at the terminating phase of the filling itself, whereby undercooling and a concomitant expansion of the medium take place. Owing to this strong expansion of the medium, an insignificant amount of the medium is left in the coupling itself.

Since pre-evacuation also takes place before the next filling and connection with the coupling, this, together with the above-mentioned expansion, contributes to ensuring that an insignificant amount, if any at all of the medium has the possibility of escaping to the surroundings.

The drawing

An example of an embodiment of the adapter according to the invention will be described more fully below with reference to the drawing, in which fig. 1 shows a sectional view of the adapter with a connection hose prior to the coupling-together, fig. 2 shows a sectional view of the coupling unit itself prior to the coup- ling-together, fig. 3 shows a sectional view of the coupling part after the coupling-together with the stub, fig. 4 shows a sectional view where the gripping means have been caused to engage, fig. 5 shows a sectional view where a positive pressure is applied for pressure testing, fig. 6 shows a sectional view where the medium is evacuated, fig. 7 shows a sectional view during filling of coolant, fig. 8 shows a sectional view after the filling, fig. 9 shows a sectional view after the disengagement, and fig. 10 shows a sectional view at the emptying of residual coolant.

Description of a working example

An example of a filling adapter according to the invention is shown in fig. 1. The adapter 1 itself comprises a rear part 3 with a supply hose 2 having a feed for coolant, pressure test gas, and ventilation in the form of a suction channel for air 4, said air being admitted 23 through openings 27 in the housing, whose interior 4 may thereby be ventilated.

The coupling unit itself is provided at the front, said coupling unit being adapted to be coupled with an inlet stub 5 with connection to the closed circuit in the cooling system.

Now, the coupling part will be described more fully. The coupling itself, which is shown in fig. 2, comprises a pneumatic actuator 6, an outer jacket 7, gripping means 8, gaskets 9 for sealing against a face, a pin 10 for opening a non-return valve 1 1 of a filling stub 5, a filling stub 5, a non-return valve 1 1 of the filling stub, with a point 12 where the pin just touches the non-return valve, an opening/closing point 13, an internal valve 14, an internal filling pipe 15, a heating member 16, a biasing unit 18, a spring 19 and a gasket holder 20.

When the coupling is composed of inter alia the above-mentioned parts, the coupling may be adopted on the filling stub 5, until the gasket 9 engages the face of the filling stub. This situation is shown in fig. 3. The filling pipe 15 of the coupling is pre-evacuated from the internal valve 14 and back. The pre-evacuation may be effective right back to the supply line.

Then, the start button on the operating unit is activated, whereby the pneu- matic actuator 6 is activated and is moved forwards, that is to the right, as will appear from fig. 4, so that the outer jacket 7 is moved correspondingly forwards and pushes the gripping means 8 into engagement with the collar of the filling stub 5. The biasing unit 18 is activated at the same time by the filling pipe 15, whereby the forces of the spring 19 are transferred to the gasket holder 20, and the gasket 9 now sealingly engages the filling stub 5. It is ensured in this manner that the gasket 9 is sealingly engaged both un- der vacuum and under pressure.

It is noted that this structure provides a safeguard against leakage - even if the air should drop out for some reason.

Thus, it appears from fig. 4 that when the outer jacket 7 is in its foremost position and the gripping means 8 are thus in full engagement with the stub 5, the biasing unit 18 and thereby the gasket 9 are mechanically "locked together", even if the actuator 6 might become pressureless and thereby inactive.

This ensures that the gasket 9 will always be in a tight position, just as the gripping means 8 cannot "release" the stub 5, and, thereby, there is no risk of escape of possible inflammable gases from the actuator, even if the pressure should cease either completely or partly.

The pneumatic actuator 6 continues forwards toward the touch point 12 of the non-return valve, as shown in fig. 5. At the same time, the internal valve 14 opens, and the volume present between the internal valve 14 and the non-return valve 1 1 is evacuated.

The pneumatic actuator 6 then continues to its end position, as shown in fig. 6. Hereby, the spring 19 is compressed maximally by the biasing unit 18, whereby the force is transferred via the gasket holder 20 to the gasket 9. The sealing to the filling stub 5 is thus both vacuum- and pressure-proof. In the meantime, the pin 10 has been advanced to the opening/closing point 13 of the non-return valve 11 , and the filling process may now be carried out. This also ensures that the non-return valve 1 1 of the filling stub 5 is affected by the actuator 6 for opening via the internal filling parts, which filling parts may preferably be the filling pipe 15, the internal valve 14, the pin 10 for opening the non-return valve 1 1 of the filling stub 5, the biasing unit 18 and the gasket holder 20 with the gasket 9.

To ensure that the medium supply is blocked when the coupling part 4 is disconnected, a pin 21 or the like may be provided, said pin 21 connecting the outer jacket with the inner coupling parts mechanically, so that if the jacket is pulled back for the disconnection of the coupling, the inner coupling parts comprising the medium supply parts will likewise be closed and removed from the filling stub 5. As the medium may change its state from liquid to gas during filling, the coupling is provided with a heating member 16, which counteracts condensation in the coupling, while ensuring that when the filling is terminated, the medium enters into a gas phase, whereby undercooling with concomitant strong expansion of the medium takes place, which leaves an insignificant amount of medium in the coupling.

In a preferred embodiment, the individual modules are secured to each other by means of only two screws, but may be secured to each other in other ways.

Then, the tightness control as well as the ventilation of possibly inflammable gases will be described more fully.

The tightness control is initiated by the supply of nitrogen, which is a non- inflammable gas, as indicated by an arrow to the hatched cavity in the filling pipe 15 in fig. 5.

All gaskets in the front part of the adapter and in the supply line itself are thus pressure-tested, so that tightness is assured.

Then, the cavity is evacuated, and a vacuum test is carried out, which is shown in fig. 6, where the exhaustion of the hatched cavity is indicated by an arrow. In this manner, all gaskets are checked for tightness at vacuum.

When both the pressure test and the vacuum test are positive, the actual filling of the inflammable medium may be initiated, as indicated by cross hatching in fig. 7.

When the filling has been completed, the pin 10 is pulled back by the actuator 6, as shown in fig. 8. Residual coolant may still be left in the adapter, which will be discharged later.

Now, the adapter may be disconnected, as shown in fig. 9.

Finally, residual coolant, if any, may be emptied, as indicated by an arrow in fig. 10.

To satisfy the ATEX Directive, and as described before, the adapter is provided with means for the ventilation of the cavity 4 in the adapter 1 , as indicated by hatching in fig. 1. This is the so-called Zone 2.

The ventilation takes place by connecting the cavity 4 with a suction channel, which communicates with a ventilator which may be mounted in the rest of the service system or optionally outside the building itself. The admission takes place via openings 22 in the housing 3, as indicated by arrows 23. If a leakage should occur in the adapter or in the hose, these possible inflammable gases will be exhausted to the rest of the service equipment, where sensors will give an alarm in case of leakage. This satisfies the requirements with respect to the handling of equipment pursuant to the ATEX Directive.