WO2022152936A1

WO2022152936A1 - Air/gas exhaust port protector configured for connection to an exhaust port of a device with a sleeve-shaped filter locked up between a ledge and a flow guider portion

Info

Publication number: WO2022152936A1
Application number: PCT/EP2022/051002
Authority: WO
Inventors: Henk Bakker
Original assignee: Asco Controls B.V.
Priority date: 2021-01-18
Filing date: 2022-01-18
Publication date: 2022-07-21
Also published as: EP4278097A1; NL2027335B1

Abstract

An air/gas exhaust port protector comprises a body (1) with an inlet portion (9) and a chamber portion (10) that branches of in outlet channels (11). A first transition wall (14) extends between the inlet and chamber portions and comprises a circumferential ledge 15 that projects forward into the chamber portion. An end cap (4) is releasably connected with a connection portion (22) to the body and delimits a head end of the chamber portion. The cap comprises a flow guider portion (25) that projects into the chamber portion. A second transition wall (26) extends between the connection and flow guider portions. A sleeve-shaped filter 2 fits inside the chamber portion with the ledge projecting into an upstream head end (18) of the filter and with the flow guider portion projecting into a downstream head end (29) of the filter.

Description

Title: Air/gas exhaust port protector configured for connection to an exhaust port of a device with a sleeve-shaped filter locked up between a ledge and a flow guider portion.

FIELD OF THE INVENTION

The present invention relates to air/gas exhaust port protectors configured for connection to an exhaust port of a device and protect it against entering of outside objects.

BACKGROUND TO THE INVENTION

Air/gas exhaust port protectors are known in various embodiments and mostly comprise some kind of robust metal hollow body that comprises a male threaded connection portion that can be screwed into a female threaded connection portion of an exhaust port of for example a high flow valve like a booster valve or another instrumentation device that from time to time quickly needs to exhaust relative large volumes of air/gas at relative high pressures of 2 bar or more. The hollow inside the body then forms a flow channel that at the location of its connection portion connects to the exhaust port and that on its opposing side connects to one or more outlet openings via which the exhausted air/gas may freely flow out into the atmosphere.

The main purpose of the air/gas exhaust protector is to prevent that in particular during periods that no air/gas is exhausted, outside objects like bugs, flies or other insects may fly or crawl into the exhaust port, and like debris or abrasive particles may end up in the instrumentation device. For that the known air/gas exhaust protectors are equipped with some kind of filter that is placed inside their flow channels upstream of their outlet openings.

A disadvantage hereof is that the functioning and durability of known exhaust port protectors leaves to be improved. At high pressure, turbulence starts to play an increasing negative role on the rate at which the volumes of exhaust air/gas can be exhausted. Furthermore it has appeared that at such high demands it may even occur that the filter gets damaged, deformed and/or displaced in such a manner that it starts blocking the outlet openings and no longer is able to prevent the outside dead or living objects from entering the instrumentation device.

Due to the high forces and turbulences it then may even occur that the filter starts to vibrate, spin and/or move back and forth at high speed inside the flow channel of the hollow protector body. When the filter is made out of a same or even harder material than the hollow protector body, this may well lead to the hollow protector body getting worn out from the inside by the quickly vibrating, spinning and/or moving back and forth filter. This may lead to dangerous situations with a part of the protector suddenly breaking off and getting forcedly blown away as a projectile. Furthermore, when the hollow protector bodies are made out of stainless steel, while the filter is also made out such stainless steel, then those are expensive components that need to be replaced. Even further this may lead to the instrumentation device getting damaged during the time the air/gas exhaust port protector is no longer functioning properly.

BRIEF DESCRIPTION OF THE INVENTION

The present invention aims to overcome those disadvantages at least partly or to provide a usable alternative. In particular the present invention aims to provide an exhaust port protector that is well able to have large amounts of air/gas flow as quickly as possible and as unhindered as possible through it, including passed through a filter that is locked up inside it.

According to the present invention this aim is achieved by an air/gas exhaust protector according to claim 1. The air/gas exhaust protector comprises a first connection portion that is configured for connection to an exhaust port of a device. The air/gas exhaust protector is configured for protecting the device against entering of outside objects like bugs, flies or other insects that otherwise may fly or crawl into the exhaust port, and like debris or abrasive particles that otherwise may accidentally end up inside the exhaust port. The air/gas exhaust protector for that comprises a hollow body with a central flow channel and one or more outlet openings, and a filter lying inside the central flow channel in front of the one or more outlet openings. The central flow channel comprises an inlet portion and a chamber portion, of which the chamber portion branches of in a plurality of sideways projecting outlet channels. A sideways projecting first transition wall extends between circumferential walls that delimit the inlet and chamber portions. According to the inventive thought, a circumferential ledge projects forward from this first transition wall into the chamber portion. The air/gas exhaust protector further comprises a removable end cap that comprises a second connection portion configured for connection to the body and delimiting a head end of the chamber portion. The end cap further comprises a flow guider portion that projects into the chamber portion. A sideways projecting second transition wall extends between circumferential walls that delimit the connection and flow guider portions. The filter is sleeve-shaped and is configured to fit inside the chamber portion with the ledge projecting into an upstream head end of the sleeve- shaped filter and with the flow guider portion projecting into a downstream head end of the sleeve-shaped filter.

Thus advantageously an exhaust port protector is provided that provides nonrestricting exhaust protection and that is able to offer an optimal flow capacity and protection against ingress of debris and dust into an exhaust port of a device. Exhaust air/gas enters through the inlet portion into the chamber portion and from there blows through the sleeveshaped filter and via the plurality of sideways projecting outlet channels into the atmosphere. With this the total cross-sectional surface areas of the plurality of outlet channels and the total effective surface area of the sleeve-shaped filter advantageously is much larger than the cross-sectional surface area of the inlet channel, which means that the flow of exhaust air/gas shall only have to experience a relative small amount of resistance when forced to flow through the inlet portion, through the chamber portion, through the sleeve-shaped filter, and through the plurality of outlet channels positioned around it. Furthermore the sleeve-shaped filter is reliably kept positioned and held locked up in axial direction between the two transition walls, and in radial direction by the ledge and the flow guider portion projecting into its outer ends. This advantageously has the effect that the sleeve-shaped filter is well able to periodically deal with truly high air/gas pressures and volumes.

The present invention thus has appeared suitable to be connected to exhaust ports of all kinds of high flow instrumentation devices that from time to time need to exhaust air/gas into the atmosphere as quickly as possible. Examples hereof are solenoid valves, control valves, pilot valves and volume boosters. The protector however also can be used on pneumatic operators, like a spring return actuator, or even combinations of such valves and operators, like an exhausting of the valve’s pressure via a protector protected exhaust port helping to return an actuator to return to its depressurized position as quickly as possible. The air/gas exhaust protector can be of robust design and even survive being stood on or run into when connected to such an exhaust port, for example in a sideways projecting position. The air/gas exhaust protector is especially suitable for process industry applications, especially oil and gas, in that it cannot only be made very robust but also to not block or freeze even for demanding applications e.g. down to -60°C (-76F).

In practice it has appeared possible to even use the air/gas exhaust protector for an expanded pressure range of 0-16 bar. Furthermore it has appeared possible to obtain a truly high flow for such an expanded pressure range, which flow even might be up to 40% higher than state of the art ones.

The removable end cap makes it possible to service the air/gas exhaust protector whenever required, for example to have it thoroughly cleaned and/or have its sleeve-shaped filter replaced. For that the body can remain in position, that is to say can remain being connected to the exhaust port. The provision of the ledge has a number of important advantages. It aids in easy placement of the sleeve-shaped filter inside the chamber portion during assembly. It helps to keep it in place during use. And, as importantly, it guides the incoming flow of exhaust air/gas away from and internally passed by the upstream head end edge of the sleeve-shaped filter. This helps to prevent the sleeve-shaped filter from starting to vibrate, spin and/or move back and forth at high speed inside the chamber portion of the central flow channel.

The exhaust port protector can advantageously be mounted with an axial direction of its chamber and/or inlet portion extending horizontally. In that orientation ingress of (rain) water is prevented, because the plurality of outlet openings can be divided around the circumference of the body, thus allowing water to easily pass through. This gives the air/gas exhaust protector a low freezing risk.

In a preferred embodiment a first head end of the sleeve-shaped filter may directly come to lie against one of the transition walls, whereas a second opposing head end of the sleeve-shaped filter then may directly come to lie against an elastically deformable sealing ring that is placed against the other one of the transition walls.

Thus advantageously the sleeve-shaped filter is automatically kept in place by means of a biasing force caused by an elastic deformation of the sealing ring, for example due to a connecting of the end cap with the body. Any tolerance differences of the body, the end cap and the sleeve-shaped filter, as well as of the chamber portion provided inside the body, then can easily be dealt with and compensated for by a lesser or bigger degree of elastic deformation of the sealing ring. Together with the locking up of the sleeve-shaped filter in between the opposing transition walls with the ledge and flow guider portion projecting into it, and together with the ledge guiding the incoming flow of air/gas away from the downstream edge of the filter, this biasing force helps to further prevent the sleeve-shaped filter from starting to vibrate, spin and/or move back and forth at high speed inside the chamber portion of the central flow channel.

In addition thereto it is then preferably the upstream head end of the sleeve-shaped filter that may abut directly against the transition wall of the body, whereas it is then the downstream head end of the sleeve-shaped filter that may press against/into the elastically deformable sealing ring that is placed against the transition wall of the end cap. This has the advantage that during exhaust the high pressure of the exhaust air/gas shall automatically press the sealing ring in place towards the second transition wall of the end cap. Furthermore, this has the advantage that during forceful exhaustion, the initial axial direction of the flow of exhaust air/gas may even force the sleeve-shaped filter further into the sealing ring thus increasing the biasing force. Even if during such forceful exhaustion the upstream head end edge of the sleeve-shaped filter should come to lie slightly spaced from the transition wall of the body, this is no problem because even then, the ledge shall keep on guiding the flow of air/gas away from and internally passed by the upstream head end edge of the sleeveshaped filter and shall keep the upstream head end of the sleeve-shaped filter radially positioned inside the chamber portion and thus properly in place in front of all outlet channels. This particularly goes for large enough sizes of the protector due to machining limitations during production.

The sealing ring may be a standard O-ring. Not only is this economic, it also may result in the sealing ring not getting damaged during assembly by sharp pointed edge parts of the sleeve-shaped filter. This is because the O-ring may well be smoothly fitted into a grooveshaped seat that is provided inside the end cap at a position around the flow guider portion and in front of the transition wall of the end cap. This smooth fitting then gives the O-ring freedom to remain at a standstill as soon as it has started gripping onto the downstream head end edge of the sleeve-shaped filter, while the end cap then remains being screwed onto/into the body by means of a threaded connection.

In addition or in the alternative the sealing ring can be made out of Acrylonitrile- Butadiene Rubber (NBR), more in particular 75 shore NBR Low Temperature. An alternative can be FVMQ. FPM (or FKM) is also a good alternative because it is well able to deal with several types of oil that could be used as lubricants in the air or part of the gasses to be exhausted. FFPM (or FFKM) is also a good alternative because it is well able to deal with fast decompression of H2S, CO2 or aggressive exhaust gasses.

Thus advantageously the air/gas exhaust protector is suitable for proper operating at a temperature range of -60 to +90°C. Even at -40°C this type of sealing ring is able to maintain at least 10% of its elasticity. Furthermore, this type of sealing ring material is also suitable for deal with not only air but also all kinds of gasses and oil lubricated air. It will not disintegrate because of them. The sealing ring preferably is made of a 70 shore hardness. Together with an allowable deformation caused by the downstream head end edge of the sleeve-shaped filter starting to press into it, it will generate sufficient force to keep the filter in place and not damage the O-ring.

An axial height of the ledge preferably may be made larger than 50% of an axial thickness of the sealing ring. This particularly goes for large enough sizes of the protector due to machining limitations during production. Thus, should the sealing ring get somewhat damaged over time, the ledge being higher than at least half the thickness of the sealing ring, shall remain being able to keep the sleeve-shaped filter neatly locked up in place in a radial sense.

In a preferred embodiment the ledge may be tapered, and comprise at least an internal angled circumferential wall. This has the advantage that the incoming flow of exhaust air/gas not only shall be guided away from and passed along the upstream head end edge of the sleeve-shaped filter, but also give it freedom to gradually start flowing into the direction of the plurality of sideways projecting outlet channels.

The sideways projecting outlet channels advantageously makes it possible to provide a plurality of them, and in particular to equally divide them around the circumferential wall of the body. For example the plurality of outlet channels then may extend substantially perpendicular/radial relative to an axial direction of the central flow channel. This makes it relative easy to machine them into the body straight towards the central chamber portion of the central flow channel. Also this makes it possible to give the outlet channels other/larger cross-sectional shapes, like slotted holes.

In a preferred embodiment the plurality of sideways projecting outlet channels may extend oblique relative to an axial direction of the central flow channel, in particular under an angle of between 25-65 degrees.

Thus advantageously an axial inflow direction of the exhaust air/gas into the inlet and chamber portions of the hollow body can smoothly be guided gradually obliquely sideways into the plurality of outlet channels. This results in a large capacity being achievable.

In a preferred embodiment the flow guider portion can be cone shaped, in particular under an angle of between 25-65 degrees.

Thus advantageously an axial inflow direction of the exhaust air/gas into the inlet and chamber portions of the hollow body can smoothly be guided gradually obliquely sideways towards the plurality of outlet channels that are divided around its circumference. This results in a large capacity being achievable. Furthermore the cone shape brings the advantage that during assembly it shall help to automatically center the end cap and sleeve-shaped filter relative to the body.

In addition thereto the oblique angle of the outlet channels then can be similar to the cone angle, such that air/gas flowing out of the inlet portion into the chamber portion there gets deflected exactly in the direction of the respective oblique outlet channels. In a preferred embodiment the chamber portion may have a cross-sectional dimension that is larger than a cross-sectional dimension of the inlet portion, and the sleeve-shaped filter may have a cross-sectional dimension that lies in between the first and second cross- sectional dimensions.

Thus advantageously no obstructions are formed inside the flow channel that may result in turbulences and building up of pressure. This also results in a large capacity being achievable.

In a preferred embodiment the sleeve-shaped filter can be a steel woven filter mesh, in particular a stainless steel woven filter mesh, more in particular with a mesh of between 100 micron - 1 mm.

Thus advantageously a durable corrosion free filter mesh is used through which the exhaust air/gas is well able to flow through substantially unhindered while at the same time preventing that all outside objects like bugs, flies or other insects, as well as debris or abrasive particles may reach the instrumentation device.

In a preferred embodiment the body and end cap can be made out of steel, in particular stainless steel.

Thus advantageously the body and end cap are robust, and resistant and usable for all kinds of aggressive or harsh environments.

In a preferred embodiment the connection between the end cap and the body can be threaded of a parallel/straight type, whereas the connection between the body and the device then can be threaded of a tapered type.

Thus advantageously the end cap can be mounted onto and removed again from the body whenever desired, without running a risk of the body screwing loose from the instrumentation device, and without a need for a glue or adhesive needing to be used between the end cap and the body.

Further preferred embodiments of the invention are stated in the dependent subclaims.

DETAILED DESCRIPTION OF THE DRAWINGS

The invention shall now be explained in more detail below by means of describing an exemplary embodiment in a non-limiting way with reference to the accompanying drawings, in which: - Fig. 1 shows a perspective view of a preferred embodiment of the exhaust port protector according to the invention;

- Fig. 2 shows an exploded view of fig. 1;

- Fig. 3 shows a cross-sectional view of fig. 1 through two of the outlet channels;

- Fig. 4 shows a cross-sectional view of fig. 1 in between the outlet channels;

- Fig. 5 shows a variant of fig. 1 with a straight/parallel threaded connection portion;

- Fig. 6 shows a photograph of a double braided preferred embodiment for a stainless steel sleeve-shaped filter mesh; and

- Fig. 7 shows a schematic drawing of the woven/braided structure that has been used for making the sleeve-shaped filter mesh.

In fig. 1-4 the exhaust port protector is shown as comprising merely four components, that is to say a stainless steel body 1 , a stainless steel sleeve-shaped filter mesh 2, an NBR sealing ring 3 and a stainless steel end cap 4.

The body 1 is mainly cylindrical shaped and delimits a central flow channel that extends through the entire body in an axial direction. At one end the body 1 is provided with a male threaded first connection portion 6, whereas on its other end it is provided with a female threaded second connection portion 7. The first connection portion 6 is configured to be screwed into a complementary threaded connection portion of an exhaust port of a device. The second connection portion 7 is configured to have a complementary male threaded connection portion of the end cap 4 screwed into.

The central flow channel starts with an inlet portion 9 of an inner diameter D9i, and continues with a chamber portion 10 of a larger inner diameter D 10i. The central flow channel ends with the female threaded second connection portion 7 of an inner diameter D7i. The chamber portion 10 branches of in six outlet channels 11 that are each drilled obliquely under an angle of 30 degrees relative to the axial direction through the circumferential outer wall of the body 1 towards the chamber portion 10. The outlet channels 11 are equally divided around the circumference of the chamber portion 10.

At the transition between the inlet portion 9 and the chamber portion 10 a first transition wall 14 is provided which comprises a tapered ledge 15 that projects forward into the chamber portion 10. At its radial inner side the ledge 15 is delimited by an oblique wall that preferably extends under a sharp angle relative to the axial direction of between 0-45 degrees. At its radial outer side the ledge 15 is delimited by an oblique wall that preferably extends under a sharp angle relative to the axial direction of between 0-45 degrees. A radially extending transition wall portion 16 is provided between the ledge 15 and an inner circumferential wall of the chamber portion 10. The sleeve-shaped filter mesh 2 is cylindrical shaped and has an outer diameter D2o that is slightly smaller than the inner diameter D10i of the chamber portion 10. Thus the sleeve-shaped filter mesh 2 fits with a narrow play inside the chamber portion 10. In the assembled position an upstream head end 18 of the sleeve-shaped filter mesh 2 lies against the transition wall portion 16, while this upstream head end 18 at a same time lies around the tapered ledge 15.

The sleeve-shaped filter mesh 2 has an axial length that is equal to an axial length of the chamber portion 10, and with that also has more than enough length to lie in front of and thus cover all outlet channels 11. The sleeve-shaped filter mesh 2 has a welding seam 19 that during assembly is to be positioned such that it does not come to lie in front of one of the outlet channels 11.

The end cap 4 comprises an end wall 21 , the male threaded connection portion 22, a groove-shaped seat 23, an axial wall portion 24, and a cone-shaped flow guider portion 25. At the transition between the male threaded connection portion 22 and the axial wall portion 24 a second transition wall 26 is provided, that here extends in the radial direction. The sealing ring 3, here an O-ring, is located in the groove-shaped seat 23 while also lying against the transition wall 26.

The axial wall portion 24 has an outer diameter D24o that is slightly smaller than an inner diameter D2i of the sleeve-shaped filter mesh 2. Thus the axial wall portion 24 fits with a narrow play inside the sleeve-shaped filter mesh 2.

As a first step during assembly the sleeve-shaped filter mesh 2 gets carefully positioned inside the chamber portion 10 in such a way that the welding seam 19 comes to lie in front of a so-called spoke, that is to say in between two of the outlet channels 11. Then as a next step the end cap 4 with the sealing ring 3 already placed inside its groove-shaped seat 23, gets screwed onto/into the body 1. With this the cone-shaped flow guider portion 25 gets to project more and more into a downstream head end 29 of the sleeve-shaped filter mesh 2.

As soon as the sealing ring 3 comes to lie in contact with the downstream head end 29 of the sleeve-shaped filter mesh 2, sharp pointed ends of the wires that make up the mesh get to grip into the sealing ring material. At a same time, sharp pointed ends of wires at the side of the upstream head end 18 get pushed against the transition wall portion 16. The sleeve-shaped filter mesh 2 together with the sealing ring 3 from that moment on are kept substantially rotationally fixed in place. Further screwing of the end cap 4, then results in the end cap 4 starting to rotate relative to the sealing ring 3 while at a same time starting to compress the sealing ring 3 in the axial direction and have it elastically deformed. This screwing preferably is done with an appropriate tool, here a pin hole spanner, such that it can be carefully monitored when a certain prescribed torque is reached.

This prescribed torque provides a perfect mating of the end cap 4 to the body 1. The materials and the tolerances with which they are made then determine the amount of elastic deformation of the sealing ring 3 and thus the biasing force with which the sleeve-shaped filter mesh 2 is kept locked up in position inside the chamber portion 10 of the body 1.

Since the angle of the cone-shaped flow guider portion 25 is the same as the angle of the outlet channels 11 , the cone-shaped flow guider portion 25, in this fully assembled state, lies optimally, that is to say flush with the outlet channels 11.

Further it is noted that an axial height hi of the ledge 15 preferably is at least equal to or larger than half the cross-sectional diameter d3 of the O-ring type sealing ring 3.

For a protector size 3/8, the ledge as an example can be made with an axial height of 2.5 mm whereas an O-ring of 2.6 mm is used.

For larger size protectors 1/2”, 3/4, 1, the ledge as an example can be made with an axial height of 3 mm whereas still an O-ring of 2.6 mm is used. For even larger size protectors 1-1/2 , 2” the ledge as an example still can be made with an axial height of 3 mm whereas an O-ring of 3.5 mm is used. Thus for those bigger O-rings higher compression force is required.

Thus for all those cases a ledge can be made, for example by means of a machining tool, that is more than high enough to keep on compensating during deteriorations of the O- ring.

However, for a protector size 1/4”, the ledge as an example can be made with an axial height of 1 mm whereas an O-ring of 2.6 mm is used. In that case the manufacturing of the ledge is limited by the machining process, and a higher axial O-ring compression is needed to compensate for that.

During operation, that is to say when the device to which the protector is connected, needs to quickly exhaust air or gas into the atmosphere, this air or gas flows out of the exhaust port straight into the inlet portion 9. From there it flows into the chamber portion 10. The tapered ledge 15 then advantageously directs the air or gas passed by the upstream head end 18 of the filter mesh 2 without exerting disturbing forces onto it that otherwise may lead to the filter mesh 2 starting to vibrate and/or rotate inside the body 1. The flow of air or gas then reaches the flow guider portion 25 that bends it straight towards the outlet channels 11. Finally the air or gas freely blows out of these outlet channels 11 into the surrounding atmosphere.

It has appeared possible to achieve very high flow capacities to flow through the protector during such exhaust periods. The 100 micron openings in the filter mesh 2 hardly have any negative influence on that. Those very high flow capacities in the exhaust of air or gas makes it possible to optimize the functioning of the device to which the protector is connected. If for example the exhaust port forms part of an actuator or valve, this may help to increase the operating/switching speed thereof. Thus the protector will not jeopardize the efficiency of for example a solenoid or booster valve. This may result in a higher total system efficiency which may safe energy. At the same time the filter mesh is well able to block dust particles and insects like mud flies from entering the device via the protector when exhaust does not take place.

In fig. 5 a side view of a variant of the protector is shown. In contrast to fig. 1-4, where the male threaded connection portion 6 of the body 1 that lies around the inlet portion 9 of the flow channel is of a tapered type, this male threaded connection portion in fig. 5 is of a straight/parallel type.

In fig. 6-7 a preferred embodiment of the sleeve-shaped filter mesh 2 is shown. It can be seen there that it has a woven structure that is braided out of two different thicknesses of stainless steel wires, warp 30 and weft 31 , in order to create an open structure of which the resistance is low cq the permeability for air/gas is large, and at a same time making it well suitable for the aimed protecting against entering of outside dirt as well as sound damping. The initially flat woven braided structure is formed into a cylinder-shape and then is plasma welded along its seam in the axial direction. The cylinder-shape advantageously makes it even stronger, and in particular well able to also withstand some forces in axial and radial direction.

The two wire thicknesses for example may be 230 pm for the warp 30 and 180 pm for the weft 31. Other thicknesses are also possible. The mesh size here can be chosen to lie between 100 micrometer - 1 mm. The lower value particularly for protection against entering of fine dust, whereas the upper value is particularly for protection against entering of certain small insects. The filter mesh thus is well able to maintain its shape and position without starting to kink or buckle.

Besides the shown and described embodiments, numerous variants are possible. For example the dimensions and shapes of the various parts can be altered. Instead of using stainless steel other kinds of materials can be used for the body, end cap and/or filter, like other metals or (carbon reinforced) plastics.

Instead of using NBR, it is also possible to use other kinds of sealing ring materials, for example FVMQ, FPM or FFPM. It is also possible to use sealing rings of other types/cross-sectional shapes. It is even possible to dispense of the sealing ring entirely. The filter mesh then comes to lie with both of its head ends locked up and/or against the respective transition walls of the body and end cap. It is also possible to use two sealing rings, one at each head end of the sleeve-shaped filter mesh. The filter mesh then comes to lie with both of its head ends locked up and/or against the respective sealing rings in front of the transition walls of the body and end cap.

It is also possible to have one or both head ends of the sleeve-shaped filter mesh manufactured with some kind of elastically deformable edge ring(s). In that case also no distinctive sealing ring(s) need to be provided nor special groove-shaped seat(s) for such sealing ring(s).

Instead of using woven/braided filter wire mesh it is also possible to use other types of filters, like for example plate material with a perforation of small flow through openings therein and formed into a sleeve-shape.

It should be understood that various changes and modifications to the presently preferred embodiments can be made without departing from the scope of the invention, and therefore will be apparent to those skilled in the art. It is therefore intended that such changes and modifications be covered by the appended claims.

Claims

1. An air/gas exhaust port protector configured for connection to an exhaust port of a device and protect it against entering of outside dirt, comprising:

- a body (1) with a central flow channel and one or more outlet openings; and

- a filter (2) lying inside the central flow channel in front of the one or more outlet openings, wherein the central flow channel comprises an inlet portion (9) and a chamber portion (10), of which the chamber portion (10) branches of in a plurality of sideways projecting outlet channels (11), wherein a sideways projecting first transition wall (14) extends between circumferential walls that delimit the inlet and chamber portions (9, 10), which first transition wall (14) comprises a circumferential ledge (15) that projects forward into the chamber portion (10), wherein the air/gas exhaust protector further comprises an end cap (4) that comprises a connection portion (22) configured for releasable connection to the body (1) and delimiting a head end of the chamber portion (10), wherein the end cap (4) further comprises a flow guider portion (25) that projects into the chamber portion (10), wherein a sideways projecting second transition wall (26) extends between circumferential walls that delimit the connection and flow guider portions (22, 25), wherein the filter (2) is sleeve-shaped and is configured to fit inside the chamber portion (10) with the ledge (15) projecting into an upstream head end (18) of the sleeveshaped filter (2) and with the flow guider portion (25) projecting into a downstream head end (29) of the sleeve-shaped filter (2).

2. Air/gas exhaust port protector according to claim 1 , wherein a first one of the head ends (18, 19) of the sleeve-shaped filter (2) abuts against its corresponding one of the transition walls, and wherein a second opposing one of the head ends of the sleeve-shaped filter (2) presses against an elastically deformable sealing ring (3) that is placed against the other one of the transition walls.

3. Air/gas exhaust port protector according to claim 2, wherein the first head end (18) of the sleeve-shaped filter (2) abuts directly against the first transition wall (14) of the body (1), and wherein the second head end (29) of the sleeve-shaped filter (2) presses against the elastically deformable sealing ring (3) that is placed against the second transition wall (26) of the end cap (4) while extending around the flow guider portion (25).

4. Air/gas exhaust port protector according to claim 2 or 3, wherein the sealing ring (3) is an O-ring, in particular made out of Acrylonitrile-Butadiene Rubber (NBR), more in particular 75 shore NBR Low Temperature.

5. Air/gas exhaust port protector according to one of the preceding claims 2-4, wherein an axial height of the ledge (15) is larger than 50% of an axial thickness of the sealing ring (3).

6. Air/gas exhaust port protector according to claim 5, wherein the ledge (15) is tapered, and comprises at least an internal angled circumferential wall.

7. Air/gas exhaust port protector according to one of the preceding claims, wherein the plurality of sideways projecting outlet channels (11) extend oblique relative to an axial direction of the central flow channel, in particular under and angle of between 25-65 degrees.

8. Air/gas exhaust port protector according to one of the preceding claims, wherein the flow guider portion (25) is cone-shaped, in particular under an angle of between 25-65 degrees.

9. Air/gas exhaust port protector according to claim 7 and 8, wherein the oblique angle of the outlet channels (11) is similar to the cone angle.

10. Air/gas exhaust port protector according to one of the preceding claims, wherein the chamber portion (10) has a cross-sectional dimension that is larger than a cross-sectional dimension of the inlet portion (9), and the sleeve-shaped filter (2) has a cross-sectional dimension that lies in between the first and second cross-sectional dimensions.

11. Air/gas exhaust port protector according to one of the preceding claims, wherein the sleeve-shaped filter (2) is a steel woven filter mesh, in particular a stainless steel woven filter mesh, more in particular with a mesh of between 100 micron - 1 mm.

12. Air/gas exhaust port protector according to one of the preceding claims, wherein the connection between the end cap (4) and the body (1) is threaded of the parallel/straight type, whereas the connection between the body (1) and the device is threaded of the tapered type.

13. Air/gas exhaust port protector according to one of the preceding claims, wherein the body (1) and end cap (4) are made out of steel, in particular stainless steel.

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