MXPA05012365A - Air dryer cartridge - Google Patents

Abstract

An air dryer desiccant cartridge, the cartridge comprising a base having an inlet and an outlet, and a casing connected to the base to define a cavity therebetween, wherein the cavity contains a filter and a desiccant, the filter being arranged upstream of the desiccant such that during normal operation fluid flow entering the cartridge through the inlet passes through the filter and then on to the desiccant before reaching the outlet, and during purging of the cartridge purge flow entering the outlet passes through the desiccant before reaching the filter, wherein further the cartridge includes a valve operable to permit a portion of the purge flow to bypass the filter.

Description

AIR DRYER CARTRIDGE DESCRIPTION OF THE INVENTION The present invention is concerned with a vehicle air dryer and in particular with a dehydrating vehicle air dryer cartridge. The provision of air drying apparatuses, hereinafter referred to as an air dryer, in vehicle air systems is well known. The air dryer apparatus is commonly placed intermediate to an air source, for example a compressor and a reservoir. The air dryer includes a dehydrating material, for example a moisture-absorbing material such as silica gel, which removes moisture from air supplied by the compressor to prevent moisture from being deposited downstream in the vehicle's air system where over time it can damage the components of the air system. To treat the accumulation of moisture in the dehydrating material, the air dryer is periodically purged to the atmosphere with dry air from the reservoir. The dehydrating purge is commonly undertaken during period when the compressor is inactive and no significant demands of dry air are made from the reservoir. The dehydrating material is commonly provided in a separable can or drum, hereinafter referred to herein Ref .: 168304 as a cartridge that is releasably attached to the air dryer. The cartridge is replaced periodically to take into account the degradation in the performance of the dehydrating material with the passage of time. It is known that the air supplied by the compressor includes a mist of very fine oil droplets. The oil drops are generated from the lubricating oil present in the compressor through the reciprocating action of the compressor. The oil mist commonly passes through the air dryer and is subsequently deposited in the tank or further downstream in the vehicle's air system. While the oil deposited in this way is much less likely to damage the components of the air system in the same way as moisture, its deposit can lead over time to problems such as, for example, the constriction of narrow passages in the air. the components of the air system and the degradation of the elastomeric seals. It is an object of the present invention to provide an improved air dryer that seeks to prevent the transmission of oil therethrough. According to a first aspect of the present invention there is provided an air dryer dehydrating cartridge, the cartridge comprises a base having an inlet and an outlet, a box connected to the base to define a cavity therebetween, wherein the The cavity contains a filter and a dehydrator, the filter is arranged upstream of the dehydrator, so that during the normal operation of the cartridge the flow of the fluid entering the cartridge through the inlet passage passes through the filter and then onto the filter. dehydrating before reaching the outlet and during the purge of the purge flow of the cartridge entering the exit passage through the dehydrator before reaching the filter wherein in addition the cartridge includes an operable valve to allow a portion of the purge flow deviate from the iltro. The inclusion of the valve ensures that all fluid entering the cartridge during normal operation is routed through the filter before reaching the dehydrator, while allowing the purge flow to be divided in such a way that a portion of the flow purge is directed through the filter in the reverse direction, while the rest of the purge flow deviates from the filter. The valve preferably includes a valve element that is urged to a closed position, thereby preventing fluid flow through the valve, by the flow of fluid entering the cartridge through the inlet. The valve element can take the form of a flexible element. In such modality, the flexible element can be provided with a proximal portion fixed to an element of the cartridge and a movable remote portion. In such an embodiment, the flexible element can be placed in a lower region of the cartridge between the filter and the base. In an alternative embodiment, the valve may comprise a flow passage having a movable valve member contained therein. The cartridge may further include a manifold associated with the filter. The collector serves to collect the liquid separated from the incoming air flow entering the cartridge. Preferably, the manifold is located in the vicinity of the valve, such that the purge flow directed through the valve entrains any liquid contained in the manifold. According to a second aspect of the present invention, an air dryer dehydrating cartridge is provided, the cartridge comprises a base having an inlet and an outlet, a box connected to the base to define a cavity therebetween, wherein the cavity contains a filter, a container inside which a dehydrator is provided and a spring arranged to drive the container and filter towards the base, where the filter is placed intermediate to the container and the base, in such a way that at least some The force applied to the container and dehydrating by the spring is transmitted to the base through the filter.

The present invention provides by this a dehydrating cartridge in which the dehydrating container and the filter are stacked one on top of the other and the force of the spring is used to place the filter and the container one in relation to the other and to the base. In such an embodiment, the filter may comprise a structural element on which a filter material is mounted. Alternatively, the filter material can be mounted on more than one structural element. In a preferred embodiment, the filter is cylindrical comprising an annular structural element on which a correspondingly annular array of filter material is carried. Preferably, the structural element is provided radially inwardly of the filter material. The dehydrating container can be substantially cylindrical. In such an embodiment, the container can be received at least partially with the filter annulus. The container may comprise a first portion having a smaller diameter than that of the annulus and a second portion having a diameter greater than that of the annulus. In such an embodiment, the transition portion of the container between the first and second portions may define a seat configured to receive the filter. According to a third aspect of the present invention there is provided a base element for a dehydrating cartridge, the base element comprises an upper portion configured to receive a filter of a dehydrating cartridge and a lower portion adapted to lean against a base of a Dehydrating cartridge, the lower portion further includes a flow passage and operable locking means for opening and closing the flow passage. In a preferred embodiment, the upper portion of the base member is provided with a seat configured to receive and support the filter. The seat can be provided with one or more coupling elements which, in service, serve to locate the filter in relation to the base element. The coupling elements may comprise one or more projections. The projections mentioned above can take the form of one or more spring fingers. Additionally, the seat can be contoured. The flow passage can be defined by a discontinuity in the lower portion of the base element. The blocking elements may comprise a flexible element comprising the discontinuity. The flexible element can take the form of a skirt or rib of a flexible plastic material. The lower portion may be provided with a plurality of flow passages. In such an embodiment, the flow passages can be defined by a plurality of discontinuities. In an alternative embodiment, the lower portion may be provided with a plurality of legs which, in use, rest against the base of a dehydrating cartridge, wherein the flow passages are defined between the legs. The base element can be provided with one or more coupling elements which, in service, are coupled with one or more elements of the base of a dehydrating cartridge. The base element can preferably be manufactured from a plastic material by an injection molding operation. The flexible rib or skirt can advantageously be co-molded with the base element. According to a fourth aspect of the present invention, there is provided a filter assembly adapted to fit between a dehydrating cartridge and an air dryer housing, the filter assembly comprising a body having an inlet, an outlet and a filter placed inside the intermediate body at the entrance and exit, the body is further provided with seals at the inlet and outlet to allow the filter to be connected in a fluid-tight manner between the dehydrating cartridge and the air dryer housing, in service. The filter assembly described above provides a autonomous component which can optionally be incorporated into an air dryer system to allow filtration of the incoming fluid before the fluid reaches the dehydrator of an air dryer cartridge. During the normal operation of the filter assembly and the cartridge the fluid flow entering the filter assembly through the inlet passage passes through the filter and then onto the cartridge through the outlet. During purging of the cartridge and purging of the filter assembly the flow entering the outlet passes through the filter before leaving the filter assembly through the inlet. The filter acts advantageously to separate particulate material, oil mist and incoming air humidity. In a preferred embodiment, the filter assembly is provided with a manifold to which the liquid separated from the fluid flow by the filter can be drained. The filter assembly advantageously includes a valve operable to allow a portion of the purge flow to deviate from the filter. The inclusion of the valve ensures that all fluid entering the filter assembly during normal operation is channeled through the filter before reaching the dehydrator, while allowing the purge flow to be divided, such that a portion The purge flow is directed through the filter in the reverse direction, while the rest of the purge flow is diverted from the filter. The valve preferably includes a valve element that is urged to a closed position, thereby preventing fluid flow through the valve, through the flow of fluid entering the filter assembly through the inlet. The valve may comprise a flow passage having a movable valve element contained therein. Modes of the present invention will now be described with reference to the accompanying figures in which: Figure 1 shows a cross-sectional side view of an air-drying cartridge according to the present invention; Figure 2a shows a partial cross-sectional view of a seat element of the cartridge of figure 1; Figure 2b shows a partial cross-sectional view of an alternative seating element; Figure 3 shows a cross-sectional view in approach of an inner portion of the cartridge of Figure 1; Figure 4 shows a cross-sectional view in additional approach of a lower portion of the cartridge of Figure 1; Figure 5 shows a partial cross-sectional view of an air-drying cartridge according to an alternative embodiment of the present invention; Figure 6a shows a side view of a valve of the air dryer cartridge of Figure 5; Figure 6b shows a perspective view of a valve seat of Figure 6a; Figures 7 and 8 show side cross-sectional views of a filter assembly according to a further aspect of the present invention and Figure 9 shows a schematic side view of a further embodiment of an air-drying cartridge according to the present invention. invention. Referring first to Figure 1 shows a cross-sectional view of a dehydrating cartridge, designated generally with the number 10, which is constructed in accordance with the present invention. The cartridge 10 includes a base member 12, a box 14 and an internal cup 16. The base member 12 is provided with a central opening 18 surrounded by a plurality of secondary openings 20. The central opening 18 is threaded so as to that the cartridge as a whole is screwed into a complementary threaded projection of an air dryer housing. The base element 12 is additionally provided with an annular seal pillar 22 bearing an elastomeric seal 24. The seal 24 ensures that, in service, the cartridge 10 fits in a leak-tight manner to an air dryer housing. A dehydrating matrix 26 comprising a moisture absorbing material such as silica gel pellets is provided within the inner cup 16. The inner cup 16 comprises a perforated base 28 having a vertical wall 30. An O-ring seal 31 is provided between the base member 12 and the perforated base 28 of the cup 16 to prevent any fluid communication therebetween. As can be seen in Figure 1, the wall is stepped in such a way that the cup 16 is provided with a lower portion 32 having a diameter that is smaller than that of an upper portion 34. The provision of the smallest diameter of the lower portion 32 defines an annular space 36 between the lower portion 32 and the box 14 within which an annular filter 38 is provided. The filter 38 is provided with an upper end 40 received in a seal 42 that abuts against the harrow 44 in the cup 26 and a lower end 46 which is also received in a seal 48 abuts against a seat element 50. The cartridge 10 is additionally provided with a perforated lid 52 received in the upper portion 34 of the cup 16 and a spring 54 disposed between the cover 52 and the box 14. The spring 54 is received in an appropriately formed seat 56 of the cover 52 and abuts against a washer 55. The filter 38 comprises an annular tube of filter material 78 which is attached to a m perforated anguide 80. The sleeve 80 acts as a load carrying element which, in service, transmits the force applied to the filter 38 by the spring 54, washer 55, cover 52 and cup 16 to the seat element 50. The filter material may comprising multiple layers of a porous material and is configured in such a manner as to cause the liquid droplets, such as oil and water, to coalesce and trap the particulate material that enters the cartridge 10. The seals 42, 48 can be of any suitable type such as for example, elastomeric "toric" gasket seals or compressible gasket type seals. In the embodiment shown, the seals 42, 48 are provided on carriers which fit around respective ends 40, 46 of the filter 38. The cup 16 is provided with a spaced plurality of fingers 82 (one of which is shown) which they are coupled with the upper seal carrier to retain the filter 38 in association with the cup 16. The seating element 50 is shown in greater detail in Figure 2a and comprises an annular base 58 having a vertical wall 60 at an inner edge Of the same. The outer edge of the base 58 is provided with a plurality of vertical fingers 62, each having a projection 64 at its distal end. In the embodiment shown, the annular base 58 is substantially flat, however it will be appreciated that the base can be configured to assist in the location and positioning of the filter 38 with respect thereto. For example, the base 58 can be provided with one or more elements, such as projections, which are coupled with complementary elements of the filter 38. The base 58 can be contoured, for example having a concave or convex shape, to assist in the location and positioning the filter 38. The lower side of the base 58 is provided at its outer edge with a peripheral rib 66 that has thereon provided a number of spaced tabs 68. Similar tabs 70 are provided in a spaced relation around the inner edge. bottom side of the base 58. in service and as can be seen in Figure 1, the tabs 68, 70 of the seal member 50 abut against the base member 12 and thereby define a number of flow openings between the base elements. tabs 68, 70, the annular base 58 and the base element 12. The seating element 50 is additionally provided with a seal element 72 that extends around the peripheral rib 66. Seal element 72 includes a flexible flange 74, in which, when viewed in cross section, it extends both radially inwardly and downwardly with respect to the rib. The seal member 72 commonly comprises a flexible plastic material such as, for example, a neoprene rubber material. As can be seen from Figure 2, the outer edge 76 of the flange 74 extends below the inner faces of the tabs 68 of the rib 66. As will be described in greater detail later herein, the sealing element can, in service, to be used to close the defined flow openings between the rib tabs 68. The seat member 50 can be formed by a molding operation of a plastic material, with the seal member 72 applied thereto by an operation of subsequent molding. This subsequent molding operation can be used to additionally mold another optional seal to the annular base 58. The additional seal 77, indicated by broken lines, consists of the same material as the seal element 72 and in service, ensures that a connection is made. leak tightness between the filter 38 and the seat element 50. The seal 77 is connected to the seal member 72 through a plurality of through holes 59 provided in the annular base 58. Figure 2b shows an alternative seating element designated in general with the number 51. The elements common to the seating element of Figure 2a are identified with like reference numbers. The seat element 51 differs in that it is provided with a plurality of projections directed inwards 61 (only one of which is shown) extending from the wall 60. The projections 61 include a tine 63 which, in service, engages with the base member 12 of the cartridge 10 by gripping edges of the secondary openings 20. The interengagement of the projections 61 and secondary openings 20 prevents the possibility of the seat member 51 moving axially relative to the base member 12 if differential pressures are experienced therethrough. The prevention of axial movement reduces the possibility of the sealing element 72 being displaced below the rib 66. The seat element 51 is shown with the fingers 62, however these can optionally be omitted. In use, the cartridge 10 is attached to the body of an air-drying apparatus (not shown) in such a manner that the incoming moist air (indicated by the arrow 84) and the oil mist (indicated by the arrow 86) of a The compressor is directed to the cartridge 10 through the secondary openings 20. The moist air and oil mist is directed between the base 28 of the cup 16 to the filter 38. After passing through the filter material 78, a significant proportion of the which oil mist is separated from the air flow. The filter material 78 acts to separate the oil mist by coalescing the individual drops forming the mist into larger droplets which are not transported by the air stream passing through the filter material 78. These larger droplets are either retained on or by the filter material 78 or drained from the filter material 78 as indicated by the arrow 86 to a peripheral manifold 88 defined between the cartridge base 12, the seat element 50 and the box 14. Advantageously, the filter material 78 further serves to separate a portion of the moisture contained in the incoming air in a similar coalescent manner. As with the oil mist, the water droplets in the incoming air are coalesced and retained in the filter material 78 or drained to the manifold 88. Figure 3 shows in amplified detail a lower portion of the cartridge 10 that includes the element sealing 72 of the seat member 50. During the normal flow of moist air and oil mist through the filter 38 there is a pressure differential across the filter 38. This pressure differential is exploited by the sealing element 72 to provide a fluid-tight seal between the base 12 and the underside of the seat member 50 as shown. The provision of this fluid-tight seal ensures that all incoming moist air and oil mist must pass through the filter 38. After passing through the filter 38, the incoming air and its remaining moisture is directed upwards between the wall inside the box 14 and the cup 16 before passing down through the dehydrating matrix 26 after which the moisture is separated and retained by the material forming the dehydrating matrix 26. The additional condensation of moisture within the air can occur as the air passes between the inner wall of the box 14 and the cup 16. The clean, dry air then passes through a fleece pad 105 that lines the base of the cup 16 and the central opening 18 of the cartridge 10 to the body of the air dryer apparatus and to a reservoir (not shown). As described in the preceding introductory paragraphs, the dehydrating material of the cartridge 10 requires periodic regeneration with dry air to prevent it from becoming saturated with moisture and hence becoming ineffective. The flow of regenerative dry air through the cartridge is in the opposite direction to that shown for moist air and oil mist and is indicated by arrows 90. The dry regeneration air from the reservoir enters the cartridge 10 through the central opening 18 before entering the cup 16 and passing through the pad fleece 105 and dehydrating matrix 26. The moist air now leaves the cup 16 through the cover 52 and passes between the cup 16 and the box 14 to the filter 38. At this point, the regeneration flow is divided in such a way that a portion thereof passes through the filter 38, while the rest deviates from the filter 38 and is used to separate any oil and water present in the filter. collector 88 as described below.

Figure 4 shows in amplified detail a lower portion of the cartridge 10 that includes the sealing element 72 of the support element 50 during the regeneration flow. The portion of the regeneration flow 90 that reaches the sealing element 72 causes the element 72 to deviate up and away from the base 12. Accordingly, the regeneration flow 90 is able to flow past the sealing element 72. while at the same time entrains any liquid retained in the manifold 88 as indicated by the arrow 92. The regeneration flow 90 and the entrained liquid 92 exit the cartridge 10 through a secondary opening 20 are vented to the atmosphere. The portion of the regeneration flow 90 that passes through the filter 38 entrains any liquid retained by the filter material 78, also as any particulate matter and vents similarly to the atmosphere through a secondary opening 20. As can be seen in Figure 4, divided portions of the regeneration flow 90 are brought together before passing through the secondary opening 20. Referring now to Figure 5 there is shown an alternative embodiment of a dehydrating air dryer cartridge according to an aspect of the present invention and designated in general with the numeral 110. The cartridge 110 includes a base 112 having a box 114 connected thereto by a seal post 116. In the embodiment shown, the seal post 116 is associated with the base 112 by providing a plurality of fingers 118 (only one of which is shown) that are received in corresponding through holes 120 d e the base 112. In order to retain the box 114 with the base 112, a rim 122 of the box 114 is received in circumferential recesses 124 of the seal post 116, such recesses 124 are crimped to hold the box 114. The stile Seal 116 further serves to support and retain a seal member 126, which, in service, ensures that an air tight seal is made between the cartridge 110 and the air dryer housing (not shown). The base 112, box 114 and seal post 116 define a cavity within which a dewatering matrix 130 is provided. The dewatering matrix 130 is provided within a substantially cylindrical support member 132 comprising a larger diameter portion 134 and a smaller diameter portion 136. The diameter portion 134 is configured to receive and support the dehydrating matrix 130 in an upper region of the cavity, while the smaller diameter portion defines a channel 138 that is aligned with an opening centrally positioned 140 of the base 112. The smaller diameter portion 136 of the support member 132 includes a shoe 142 that abuts an O-ring seal 144 of the base 122. An annular inlet chamber 146 is defined between the base 112, box 114 and smaller diameter portion 136 of the support element 132. The large diameter portion 134 of the support element 132 is di mentioned in relation to the box 114, in such a way that an annular passage 148 is provided around it. The annular passage 148 provides a communication path in the inlet chamber 146 and a space 150 above the dehydrating matrix 130. The support member 132 and dehydrating matrix 130 are retained in position with the cavity by the provision of a spring 128. which acts between a perforated lid 129 which is superimposed on the die 130 and the box 114. The cartridge 110 is further provided with a filter assembly, generally designated with the number 152, which is positioned within the box 114 between the base 112 and the support element 132. The assembly 152 comprises a filter element 154, a support ring 156 of the lower filter element and an upper filter support ring 157. The filter element 154 and the support rings 156157 define the inlet chamber 146 in respective first and second portions 158, 160. The seal elements 162, 164 are provided to prevent fluid flow through the interfaces made between the assembly 152, the support element 132 and the case 114. The support ring 156 is additionally provided with a manifold 166 which is positioned in the second portion 160 of the inlet chamber 146. The manifold 166 includes a drain valve 168, which, under certain operating conditions, it allows the liquid collected in the manifold 166 to drain to the first portion 158 of the inlet chamber 146. The filter element 154 comprises a plurality of layers of filter media. The media of each layer may comprise, for example, a plate composed of glass microfibers or an appropriate plastic material. The layers may be in intimate contact with each other or alternatively may be spaced apart by the provision of appropriate separator means. The filter element has a construction similar to that of the first embodiment mentioned in that it comprises a perforated load carrying support to which the filter means are attached. Advantageously, the cartridge 110 is provided with operable pressure relief means in case the filter element 154 is blocked. The seal element 162 between the assembly 152 and the support element 132 can be adapted to fall in a controlled manner if the pressure differential across them exceeds a predetermined value. Alternatively, the support element 132 may be arranged to separate from the filter element 154 against the action of the spring 128 to define a flow path therebetween. Figures 6a and 6b show the drain valve 168 in greater detail. The valve 168 includes an inlet 170 in fluid communication with the manifold 166 and an outlet 172 in fluid communication with the first portion 158 of the inlet chamber 146. Between the inlet 170 and the outlet 172 a valve chamber 174 is provided which contains a valve element 176, which in the embodiment shown, is substantially spherical. The chamber is additionally provided with a seat 178 for the valve element 176 surrounding the inlet 170 and a plurality of deflection channels 180 adjacent the outlet 172. The valve member 176 is longitudinally movable within the valve chamber 174 as it is indicated by arrow 182. A plurality of castellations 173 are provided around outlet 172 to ensure that it is not blocked by valve member 176. In the embodiment shown, valve chamber 174 is substantially perpendicular to the base. 112 of the cartridge 110. It will be appreciated that such an arrangement maximizes the influence of gravity on the valve element 176 and further promotes drainage of the manifold 166 during periods when the compressor is out of charge. It will be appreciated that an alternative embodiment, the valve chamber 176 may be inclined.

The operating states of the cartridge 110 will now be described. In service, it will be understood that the cartridge 110 is connected to an air dryer housing. The connection is commonly effected by the provision of a threaded portion of the base 112 that is adapted to receive a corresponding threaded portion of an air dryer housing. When the compressor of the air system in charge, moisture and contaminated air and oil mist are supplied to the first portion 158 of the inlet chamber 146 via the through holes 120 of the base. Then the moist air and oil mist pass through the filter element 154 to the second portion 160 of the inlet chamber 146. The air is prevented from passing through the drain valve 168 since the pressure differential through of the valve 168 maintains the valve element 176 against the seat 178 and from here it closes the inlet 170. The air received in the second portion 160 of the inlet chamber 146 subsequently passes via the annular passage 148 to the space 150 above the dehydrating matrix 130. Then the air passes through the dehydrating matrix 130 after which the moisture entrained in it is eliminated. The dry air subsequently exits from the cartridge 110 via the channel 138 and the opening 140. It will be understood that the air received in the first portion 158 of the inlet chamber 146 of the compressor is saturated with water and is contaminated with a compressor oil mist. and particulate material such as powder. The filter element 154 is configured to coalesce at least a significant proportion of the oil mist, so that the collector 166 can be drained and the passage of the particulate material prevented. As described above in relation to the first embodiment, the filter element 154 further acts to coalesce a portion of the water contained in the incoming air. The water and oil subjected to coalescence are initially retained by the filter element 154 and can subsequently be drained to the manifold 166. Additional condensation may occur in the annular passage 148 as the air cools. Any such condensate is capable of draining to the inner part of the box 114 to the manifold 166. As described above, the air and water subjected to coalescence are retained in the manifold 166 while the drain valve 168 is closed. The drain valve 168 is arranged to open when the pressure differential across it is either equalized or inverted. The pressure differential can be matched when the compressor is taken out of charge and hence no longer supplies air to the inlet chamber 146. The force that drives the valve member 176 against the seat 178 is thereby eliminated by allowing the element valve 176 moves under the force of gravity towards the outlet of the valve 176. Then, the liquid retained in the manifold 166 can pass through the chamber of the valve 174 to the outlet 172 via the deflection channels 180. An annular drain 184 is provided in the base 112 which is in fluid communication with the through holes 120 of the base 112. The reversal of the pressure differential through the valve 168 occurs during the regeneration of the dehydrating matrix 130 when the air dry is purged back through the cartridge 110. The valve member 176 moves in the manner described above under the influence of the pressure applied through the inlet. valve 170. It will be appreciated that any liquid collected in the manifold 166 is forced through the valve 168 into the drain 184 and subsequently out of the cartridge 110 via the holes 120. The valve 168 is configured in such a way that not all the dry air is apt to pass through it, with the result that a portion of the dry air must pass through the filter 154. As described above, this drags the water and oil retained in the filter 154, which are subsequently vented to the atmosphere. Referring now to Figures 7 and 8, a further embodiment of the present invention is shown. Components common to those of the embodiment in the invention shown in Figure 5 to 6b are identified with corresponding reference numbers. The embodiment of Figures 7 and 8 differs in that the contaminant filter assembly 152 is provided within a separate housing 186 located between the body of the air dryer 188 and the cartridge 190 containing the dehydrator. The housing 186 contains the filter element 154, the manifold 166, the drain valve 168 and further defines the two portions 158, 160 of the inlet chamber 146. The filter element 154 is retained in the housing by an upper plate 187 In the embodiment shown, the clamping force between the cartridge 190 and the body of the air dryer 188 is transmitted through an external wall of the housing 186. It will be appreciated that in an alternative embodiment, this force can be transmitted through both. of the upper plate 187 as the filter element 154. In such an embodiment, the filter element 154 is reinforced to be able to compensate for the force transmitted through it without deformation or structural failure. Thus, the filter element 154 can be constructed in a manner similar to that of the embodiment of Figure 1, that is, comprising one or more structural elements on which a filter material is mounted. The housing 186 is annular having a central opening through which a hollow projection 192 of the body 188 goes into service. The projection 192 is provided with a portion of the threaded end 194 that is adapted to engage with a corresponding threaded portion 196 of the base 112 of the cartridge. In service, the housing 186 is sandwiched between the cartridge 190 and the body 188. The sealing rings 126, 198, 200, 202 are provided to ensure leak-tight seals between the respective components 186, 188, 190. The valve drain 168 has a configuration similar to that of the embodiment of Figures 5 to 6b, ie, a valve member movable by a pressure differential therethrough to close valve 168 during normal air flow to and through the cartridge 190 and movable to move the valve either by gravity when the compressor is discharged or by the regeneration flow through the cartridge 190. In service, compressor air enters the first portion 158 of the inlet chamber 146 via a gate 204 of the body 188 of the air dryer as indicated by arrows 206. Then the compressed air passes through the filter element 154 to the second portion 160 of the intake chamber. 146. As before, the oil and water coalesced by the filter element 154 can be drained to the manifold 166 at the base of the second portion 160. Then the compressed air passes through an inlet 120 into the cartridge 190 after which is conventionally dried by the dehydrating 130. The manifold 166 is drained either by gravity when the compressor air supply is stopped, or by the backflow of dry air through the cartridge 190 to regenerate the dehydrator. This second instance is illustrated in Figure 8 by the keys 208. The liquid of the manifold 166 is at the im- posing to the gate 204 and thereafter ventilated to the atmosphere through a vent gate (not shown) of the body 188 of the air dryer. As before, the regeneration of the dry air is divided between the filter element 154 and the drain valve 168. The portion passing through the filter element 154 entrains any liquid or particulate material retained by the material of the filter element 154. The portion of the regeneration flow passing through the drain valve 168 drains any liquid retained in the manifold 166. The filter assembly 152 of FIGS. 7 and 8 can be used in conjunction with a cartridge containing a filter. of the type described with reference to Figures 1 to 6b to provide additional liquid and debris removal. Alternatively, the filter assembly 152 can be used in conjunction with a conventional cartridge containing only dehydrating material.

Referring now to Figure 9 there is shown a dehydrating cartridge, generally designated 210, according to a further embodiment of the present invention. The cartridge 210 comprises a base 212 and a box 214 defining between them a cavity 216. Disposed within the cavity 216 is a dehydrating matrix 218 and a contaminant filter assembly 220. The assembly 220 comprises a first filter bed 222, a second filter bed 224, a manifold 226, a drain 228 and a drain valve 230. The cartridge 210 further includes a unidirectional valve 232 positioned intermediate the dehydrating matrix 218 and the contaminant filter assembly 220, a drain of dehydrating regeneration 234 and a dehydrating regeneration drain valve 236. In service, the compressor air is fed to the cartridge 210 in a conventional manner as indicated by the arrows 240. Air passes via an annular passage 238 defined between the dehydrating matrix 218 / contaminant filter assembly 220 and the box 214 to the upper part of the cavity 216 before passing successively through the filter beds 222, 224. It will be noted that a unidirectional valve 223 is provided between the beds 222, 224. The oil and moisture released from the incoming air are deposited in the collector. 226. Then the air passes through the dehydrating matrix 218, after which additional moisture is removed. Then substantially dry air exits subsequently from the cartridge 210 through an outlet 242 in the base 212. The flow of regeneration air through the cartridge 210 is indicated by the arrow 244. The dry air from a reservoir enters the cartridge 210 a through the outlet 242 and passes through the dehydrating matrix 218 to release the moisture retained therein. Most of this now moist air enters the regeneration drain 234 and is vented to the annular passage 238 through the drain valve 236. A portion of the wet regeneration air enters the manifold 226 via the unidirectional valve 232 and thereby drives any liquid retained therein through the drain 228 and the drain valve 230 to the annular passage 238. The humid air and any moisture in the collector 226, as indicated by arrows 246, is then vented to the atmosphere through an orifice of ventilation of the body of the air dryer (not shown). It is noted that, in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (35)

CLAIMS Having described the invention as above, it is claimed as property, contained in the following claims:

1. A dehydrating air dryer cartridge, the cartridge is characterized in that it comprises a base having an inlet and an outlet and a box connected to the base to define a cavity therebetween, wherein the cavity contains a filter and a dehydrator, the The filter is arranged upstream of the dehydrator, so that during normal operation, the flow of fluid entering the cartridge through the inlet passes through the filter and then into the dehydrator, before reaching the outlet and during purging. of the cartridge, the purge flow entering the outlet passes through the dehydrator before reaching the filter, wherein the cartridge further includes an operable valve to allow a portion of the purge flow to deviate from the filter.

2. The air dryer dehydrating cartridge according to claim 1, characterized in that the valve includes a valve element that is driven to a closed position, thereby preventing the flow of fluid through the valve, by means of the flow of the valve. fluid that enters the cartridge through the inlet.

3. The dehydrating air dryer cartridge according to claim 2, characterized in that the valve element takes the form of a flexible element.

4. The air dryer dehydrating cartridge according to claim 3, characterized in that the flexible element is provided with a proximal portion fixed to an element of the cartridge and a movable remote portion.

5. The air dryer dehydrating cartridge according to claim 3 or claim 4, characterized in that the flexible element is positioned in a lower region of the cartridge between the filter and the base.

6. The air dryer dehydrating cartridge according to claim 1 or claim 2, characterized in that the valve may comprise a flow passage having a movable valve element contained therein.

The dehydrating air dryer cartridge according to any of the preceding claims, characterized in that the cartridge further includes a collector associated with the filter.

8. The air dryer dehydrating cartridge according to claim 7, characterized in that the collector is located in the vicinity of the valve, in such a way that the purge flow directed through the valve entrains any liquid contained in the collector. .

9. A dehydrating air dryer cartridge, the cartridge is characterized in that it comprises a base having an inlet and an outlet, a box connected to the base to define a cavity therebetween, wherein the cavity contains a filter, a container within the which is provided a dehydrating and an arranged spring to push the container and filter towards the base, where the filter is positioned intermediate to the container and the base, in such a way that the force applied to the container and dehydrating, through the spring, is transmitted to the base by means of the filter.

The dehydrating air dryer cartridge according to claim 9, characterized in that the filter comprises a structural element on which a filter material is mounted.

11. The air dryer dehydrating cartridge according to claim 10, characterized in that the filter is cylindrical and comprises an annular structural element on which an array of correspondingly annular filter material is carried.

12. The air dryer dehydrating cartridge according to claim 11, characterized in that the structural element is provided radially inwardly of the filter material.

13. The dehydrating air dryer cartridge according to claim 11, characterized in that the structural element is provided radially outwardly of the filter material.

14. The air dryer dehydrating cartridge according to any of claims 11 to 13, characterized in that the filter includes a plurality of structural elements.

15. The dehydrating air dryer cartridge according to any of claims 11 to 14, characterized in that the dehydrating container is substantially cylindrical.

16. The air dryer dehydrating cartridge according to claim 15, characterized in that the container is received at least partially with the annulus of the filter.

17. The air dryer dehydrating cartridge according to claim 15 or claim 16, characterized in that the container comprises a first portion having a diameter smaller than that of the annulus and a second portion having a diameter greater than that of the annulus. .

18. The air dryer dehydrating cartridge according to claim 17, characterized in that the transition portion of the container between the first and second portions defines a seat configured to receive the filter.

19. A base element for a dehydrating cartridge, the base element is characterized in that it comprises an upper portion configured to receive a filter of a dehydrating cartridge and a lower portion adapted to lean against a base of a dehydrating cartridge, the The lower portion further includes a flow passage and operable locking means for opening and closing the flow passage.

20. The base element for dehydrating cartridge according to claim 19, characterized in that the upper portion of the base element is provided with a seat configured to receive and support the filter.

21. The base element for dehydrating cartridge according to claim 20, characterized in that the seat is provided with one or more coupling elements which, in service, serve to locate the filter in relation to the base element.

22. The base element for dehydrating cartridge according to claim 21, characterized in that the coupling elements comprise one or more projections.

23. The base element for dehydrating cartridge according to claim 22, characterized in that the projections take the form of one or more spring fingers.

24. The base element for dehydrating cartridge according to any of claims 19 to 23, characterized in that the flow passage is defined by a discontinuity in the lower portion of the base element.

25. The base element for dehydrating cartridge according to claim 24, characterized in that the blocking means comprise a flexible element that spans the discontinuity.

26. The base element for dehydrating cartridge according to claim 23, characterized in that the flexible element takes the form of a skirt or rib of a flexible plastic material.

27. The base element for dehydrating cartridge according to any of claims 19 to 26, characterized in that the lower portion is provided with a plurality of flow passages.

28. The base element for dehydrating cartridge according to claim 27, characterized in that the flow passages are defined by a plurality of discontinuities.

29. The base element for dehydrating cartridge according to claim 27, characterized in that the lower portion is provided with a plurality of legs which, in service, bear against the base of a dehydrating cartridge and where the flow passages They are defined between the legs.

30. A filter assembly for fitting into a dehydrating cartridge and an air dryer housing, the filter assembly is characterized in that it comprises a body having an inlet, an outlet and a filter positioned within the intermediate body at the Inlet and outlet, the body is additionally provided with seals at the inlet and outlet, to allow the filter to be connected in a fluid-tight manner between the dehydrating cartridge and the air dryer housing, in service.

31. The filter assembly according to claim 30, characterized in that the assembly is provided with a manifold within which the liquid separated from the fluid flow by the filter can be drained.

32. The filter assembly according to claim 31, characterized in that the filter assembly advantageously further includes a valve operable to allow a portion of the purge flow to deviate from the filter.

33. The filter assembly according to claim 32, characterized in that the valve includes a valve element that is driven to a closed position, thereby preventing the flow of fluid through the valve, by the flow of the fluid entering the assembly filter through the entrance.

34. The filter assembly according to claim 32 or claim 33, characterized in that the valve comprises a flow passage having a movable valve element contained therein.

35. The filter assembly according to claim 34, characterized in that the valve element is driven to an open position by gravity.