The present invention concerns a housing for a liquid- injected screw-type compressor element, which housing is provided with a recess for the spiral bodies of the rotors of the compressor element and the bearing housings for the bearings of the shafts of the rotors, as well as with an inlet, an outlet and at least one injection point for lubricating liquid.

With a liquid-injected screw-type compressor element, a liquid for the lubrication, cooling and sealing of the rotors is injected on the spiral rotors. The lubricating liquid is discharged together with the compressed gas, separated from the gas in a separator, cooled and subsequently injected again.

Traditionally, the housing of such a screw-type compressor element consists of a tubular rotor casing provided with recesses for the spiral rotors, a first bearing housing part provided at one end of the rotor casing and having the bearing housing for the rotor shafts at this far end, and a second bearing housing part provided at the other end of the rotor casing and having the bearing housing for the rotor shafts at this other end. The bearing housing part may also form a lid at one far end through which protrudes for example the driving shaft of one of the rotors and which is possibly provided with a flange for fixing a gear

case. The other bearing housing part may also form a lid or it can be provided with entries to the rotor shafts which are sealed by means of shaft lids.

Thus, the two bearing housing parts are necessary for the assembly of the bearings of the rotor shafts.

The supply line of the liquid to be injected and the discharge pipe of the compressed gas are connected to the bottom of the rotor casing or a lid by means of a separate housing connected to said rotor casing. or said lid.

Due to the large number of components, the production is relatively expensive and the assembly is time-consuming.

Moreover, a lot of mechanical finishing is required after the components have been cast.

The components are cast and mechanically finished afterwards. Thus, the recess for the rotors in the rotor casing is bored out to size. Especially with rotors having a great length, this recess can be axially rather long, so that it is difficult to provide this recess with great accuracy over the entire length by means of a tool.

The present invention aims a housing for a liquid-injected screw-type compressor element which does not have the above-mentioned disadvantages and which has a minimum of components, allowing for a quick production and assembly, and whereby the recess for the rotors can be easily milled out with great accuracy, also in the case of relatively long rotors.

This aim is reached according to the invention in that the housing has two parts which are fixed to one another, namely an inlet part with the inlet and an outlet part with the outlet, each comprising a part of the recess for the bodies of the rotors, and in that the bearing housings for the rotor shafts are integrated in the far ends of said inlet and outlet parts on both ends of the housing.

Thus, no separate bearing housing parts are required, as a result of which the number of components is restricted.

Both parts of the housing are preferably provided with a flange on the far ends which are fixed to one another for said fastening.

At least one of the parts of the housing, for example the part on the inlet side, can be sealed on its far end on the side of the bearing housing, preferably by means of a wall integrated in said part.

The other part of the housing can be sealed on its far end on the side of the bearing housing, to the exception of openings for the bearings.

The latter part of the housing can also be provided with a connecting flange on its far end on the side of the bearing housing in view of the connection of a case, for example a gear case.

The inlet part of the housing is preferably provided around the inlet of a connecting flange, in view of the assembly of the housing of an inlet valve.

In the outlet part of the housing can be integrated a duct for lubricating liquid connecting to the injection point.

This outlet part can also be provided with a connecting flange for the assembly of the housing of a lubricating liquid valve and/or the housing of an outlet valve, whereby the connecting flange is preferably common to both valves.

In order to better explain the characteristics of the invention, the following preferred embodiment of a housing for a liquid-injected screw-type compressor element according to the invention is described as an example only without being limitative in any way, with reference to the accompanying drawings, in which: figure 1 represents a top view of the housing of a screw-type compressor element according to the invention; figure 2 represents a side view of the housing from figure 1 ; figure 3 represents a section according to line III- III in figure 2, with the rotors of the compressor element; figure 4 represents a bottom view of the housing according to the preceding figures;

figure 5 represents a view in perspective of the inlet part of the housing according to the preceding figures, drawn to a larger scale ; figure 6 represents an end view of the inlet part of the housing according to the preceding figures; figure 7 represents a view in perspective analogous to that in figure 5, but of the outlet part of the housing; figure 8 shows a view in perspective according to arrow F8 in figure 7.

The housing, represented in figures 1 to 4, is designed for a screw-type compressor element with two rotors 1 and 2.

As is represented in figure 3, the male rotor 1 consists of a spiral body 3 and two shafts 4 and 5 standing on the far ends of the body 3 and supported on bearings 6 and 7. The shaft 5 protrudes outside the housing and is the drive shaft. The female rotor 2 also consists of a spiral body 8 which works in conjunction with the body 3 and is also driven by this body 3, and of two shafts 9 and 10 on the far ends of the body. The shafts 9 and 10 are supported on bearings 11 and 12.

The housing comprises two parts which are connected to one another, namely an inlet part 13 and an outlet part 14, in each of which is integrated a bearing housing 15,16 respectively.

The inlet part 13, which is represented as separate in perspective in figures 5, is provided with a recess 17 for a part of the two rotors 1 and 2, whereas the outlet part

14, represented as separate in perspective in figures 7 and 8, is provided with a recess 18 for the remainder of the two rotors 1 and 2.

The inlet part 13 and the outlet part 14 each have a connecting flange 19,20 respectively on their far ends which are connected to one another. These flanges 19 and 20 are fixed to one another by means of bolts 21.

The inlet part 13 is further provided with a bearing housing 15 for the aforesaid bearings 6 and 11, on the far end of the inner side which is turned away from the outlet part 14. On its outer side, said inlet part 13 is sealed by means of a wall 22 which is an integral part of the inlet part 13. This wall 22 thus forms a lid integrated in the inlet part 13 of the housing.

Near this bearing housing 15, the inlet part 13 is provided with an inlet 23 at the top, opening into the recess 17 and forming a small, outwardly projecting room. On the outside, this inlet 23 ends in a connecting flange 24 for fixing the housing of an inlet valve.

In an analogous manner, the outlet part 14 has a bearing housing 16 for the bearings 7 and 12 on its far end on the inner side which is turned away from the inlet part 13.

On this far end, the outlet part 14 has a connecting flange 25 for fixing a case, for example a gear case.

The connecting flange 25 is not always required. When the drive of the shaft 5 does not have any gear wheels, for example when the drive motor is coupled directly to the shaft 5, this outlet part 14 can be made without a connecting flange 25.

Further, this far end is not entirely sealed, but provided with an opening 26 for the assembly and adjustment of the bearing 7 as well as the passage of the driven shaft 5, and with an opening 27 for the assembly and adjustment of the bearing 12. Both openings 26 and 27 are surrounded with an elevation 28 on the outside, provided with holes 29, with internal screw thread for fixing rings 30 to fix the bearings 7 and 12.

At the bottom, the outlet part 14 is provided with the outlet 31 for the compressed gas forming a short duct.

This outlet 31 is connected to the recess 18 and connects to a connecting flange 32 for fixing the housing of an outlet flap on the outside.

In the wall of the outlet part 14 has been integrated a supply duct 33 for the lubricating liquid to be injected, opening into the recess 18 via one or several injection points 34. The integration of a part of the supply of lubricating liquid in the outlet part 14 reduces the number of components that have to be cast.

Moreover, it is possible that this supply duct 33 opens into the same connecting flange 32 on the outside as the outlet 31. The form and shape of this connecting flange 32

have been adjusted to make it possible to assemble the housing of the lubricating liquid valve as well. As this connecting flange 32 is common, the finishing is simplified, while the outlet valve and the lubricating liquid valve can be provided in a common housing, so that the assembly on the housing of the compressor element can be done in a faster manner.

On the outside of the inlet part 13 as well as of the outlet part 14 are provided reinforcing ridges 35 which also have a positive effect on the sound level.

All the flanges 19, 20, 24,25 and 32 have been integrated in the housing so that, without counting the bolts 21 and the rings 30, the housing is in fact made up of only two castings forming the inlet part 13 and the outlet part 14 respectively. Moreover, the inlet part 13'and the outlet part 14 are designed such that it becomes possible to finish all the machining of the castings in a single set- up.

This considerably reduces the time required for the mechanical finishing.

The invention is by no means limited to the above-described embodiments represented in the accompanying drawings; on the contrary, such a housing for a liquid-injected screw- type compressor element can be made in all sorts of variants while still remaining within the scope of the invention.