FI117161B - Method and arrangement for attaching a filter to a respirator - Google Patents

Description

117161

FIELD OF THE INVENTION The present invention relates generally to inter-component joints in a respirator for removing harmful substances from the respiratory air. In particular, the invention relates to attaching a filter to the blower part of a ventilator.

Modern breathing apparatus 100 generally has, as shown in Figure 1, a face portion 101, 10 intended to be strapped to the user's face by means of straps, and a fan portion 102 containing a fan (not separately shown) that draws air through the filter or filters 103 and blows air through hose 104 to face portion 101. Filters 103 are generally disposable. Filters with different filtering properties can be attached to the ventilator, depending on the environment in which the ventilator user will operate. Common types of filters include, for example, particle filters and flue gas filters

Fig. 2 is a sectional view of a known procedure for attaching a filter 103 to a fan portion 102. The filter has a threaded neck 201 having an outer thread 202 on the outside surface 202. The fan portion 102 has: a recess 203 having an internal thread 204 on its bottom. is a step 205 against which an annular rubber gasket 206 is placed.

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When the filter 103 is attached to the fan section 102 by rotating its threaded neck 201 into the recess 203, the outer end of the threaded neck 207 depresses the rubber seal

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; 25 206 and seals the connection between the filter and the fan part.

One of the disadvantages of the prior art sequenced system is that the filter has to be rotated all the way to the bottom of the thread to make the joint tight. If the filter is not properly screwed in, the connection between the filter and the fan section will leak, which may be fatal for the user. On the other hand, standard DEN 3182 *. determines the length of the thread of the filter so that, when the filter is twisted, the threads remain visible, so that the threads easily collect dirt and dust. If the machine is used in an environment where the dirt and dust contain harmful substances, the dirt and dust accumulated in the threads can be dangerous over time.

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It is an object of the present invention to provide a method and arrangement for attaching a filter so that the sealing of the joint is not dependent on whether the filter is fully screwed or not. It is also an object of the invention to provide a filter mounting arrangement which is advantageous in manufacturing technology. A further object of the invention is to provide an arrangement that reduces the accumulation of dirt and dust in the threads of the filter.

The objects of the invention are achieved by providing a sealing point on the inner surface of the filter attachment neck.

The arrangement according to the invention is characterized in that it comprises the features set forth in the characterizing part of the independent claim 10 directed to the arrangement.

The invention also relates to a method, characterized in that it comprises the functions set forth in the characterizing part of the independent claim to the method.

15

According to the invention, a cylindrical portion may be formed in the portion of the breathing apparatus to which the filter is attached, which, when the filter is attached, protrudes into the threaded neck of the filter. The part of the filter having prior art threads is generally referred to as a clamping neck. A sealing point may be formed between the outer surface of the cylindrical portion 20 and the inner surface of the filter attachment neck by inserting between the surfaces, for example, an elastic element known per se: **; Material O-ring. The closer the sealing point thus formed is to the outer end of the cylindrical portion, the less the tightness of the arrangement is sensitive to whether the filter is properly screwed in or not. The invention does not exclude the possibility that the fastening arrangement also has a prior art seal: double sealing further improves product safety.

The invention is very well applicable to a modular fan section having a separate fan module, which can be fitted with suction duct modules of various shapes and sizes * *: 30, which can be further connected with a suitable number of filter · [[[· mia. According to a preferred embodiment, the filter is connected directly to the cylindrical portion in the fan module by the arrangement according to the invention. The suction * * λ / duct module may then be a simple support section that does not have an actual suction duct but merely supports the connection of the filter to the fan module.

: v 35 * * * • ·· • · 3 117161

The invention will now be described in more detail with reference to exemplary preferred embodiments and the accompanying drawings, in which Figure 1 illustrates a known respirator, 5 Figure 2 illustrates known stiffening for mounting a filter, Figure 3a illustrates a principle of the invention, Figure 3b applied to a modular blower part, Figure 5 shows the principle of Figure 3a applied to another modular blower part, and Figure 6 shows a variant of the invention.

1 and 2, so that in the following description of the invention, reference will be made mainly to Figures 3a to 6. In the drawings, the same reference numerals are used for like parts.

Fig. 3a is a partial sectional view of the filter 301 and the other part 302 of the ventilator, which may be, for example, a suction duct module 20i of a modular fan section. The filter has a retaining neck 303 having an exterior thread 304 on its outer surface per se in this embodiment of the invention, as defined by DIN 3182 as defined in the prior art. The wall of the recess 302 has a corresponding internal thread 305. The 302 also has a cylindrical portion 306, which. is coaxial with the thread 305, so that when the filter 301 is screwed in, the cylindrical portion 306 extends into the filter retaining neck 303.

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The exterior surface of the cylindrical portion 306 is rotated by a groove 307 having a prior art sealing ring made of elastic material, such as an O-ring 308. The depth of the groove 307 is less than the thickness of the O-ring 308: the ring 308 is in the groove 307, its outer surface is slightly raised from the outer surface of the cylindrical: T: 30. The outer diameter of the cylindrical portion 306 is smaller than the inner diameter of the filter mounting neck 303 such that the cylindrical portion fits well inside the mounting neck; however, the thickness of the ring is * so large that the inner surface of the filter clamping collar is pressed tight against the O-ring to form a tight connection between the inner surface of the clamping collar 303 and the outer: 35 surface of the cylindrical portion 306.

Figure 3a shows that the tightness of the connection between the filter 301 and the part 302 is not very sensitive to whether the filter is properly screwed in or not. If the inner surface of the filter engaging collar 303 is substantially rectangular, the filter may be rotated helically (wherein the filter moves upwardly relative to the image position) until the outer end of the collar 303 is flush with the O-ring 308, without . The closer the groove 307 is to the distal end (upwardly pointing in the figure) of the cylindrical 5-member portion 306, the further the filter can be rotated out of place without the connection beginning to leak.

Figure 3b is a partial cross-sectional view of another embodiment of the invention, otherwise similar to that of Figure 3a, but incorporating a prior art seal ring 320. The inner end 305 of the inner thread 305 of the member 302 has a plane 321 against it. seal ring 320 is set. When the filter 301 is fully screwed in, the outermost end of its clamping collar is pressed against the sealing ring 320 in the same manner as in prior art solutions. However, since the stiffener shown in Fig. 3b also has a sealing point according to the invention between the outer surface of the cylindrical portion 306 and the inner surface of the clamping neck 303, this solution achieves a very high operational safety: the seal between the filter and 302 has two sealing points; and even if the filter is accidentally rotated slightly open, there is still one more sealing point.

··· * * · «*: Fig. 4 is a partial sectional view of a modular fan section 400, which consists of a fan module 401, a suction duct module 402, and filters 403 * *. and 404. The suction duct module 402 is secured to the fan module 401 by partially pushing the 1 fan module into a cylindrical socket portion 405 • *: m // in the suction duct module and tightening the collar 406 around the socket portion 405 and inside the fan * · * module. There may be a hole in the connector portion 405, the collar 406, and on the outside of the fan module 401 for the breathing apparatus face hose; the hose and the hole are not shown for clarity. On the other hand, the hose: T: 30 can also be provided with an attachment point at a position on the fan module that does not enter the connection portion 405, whereby the connection portion 405 and the collar 406 do not need • m. be a hole for it. When the fan module 401 and the suction duct module 402 are attached to each other, the cylindrical portion 407 in the fan module is inserted into the suction duct 408 in the suction duct module. A joint is formed between the outer surface 35 of the cylindrical portion 407 and the inner surface of the suction passage 408, which may be improved if desired by inserting an O-ring 410 of elastic material into a groove 409 rotating the outer surface of the cylindrical portion 407.

5,117,161

The suction duct module 402 has attachment points for two filters 403 and 404, the filter 403 and its sealing gaskets are shown removed, and the filter 404 and its sealing gaskets are shown affixed. The attachment points have the same structure as in Fig. 3b, that is, each of the 5 attachment points has an internal thread that fits outside the filter attachment neck and a cylindrical portion extending into the filter attachment neck when the filter is screwed into place with an O-ring 411, 412. The joints between the suction duct module 402 and the filters 403 and 404 are sealed by the O-ring 411, 412 and further, when the filters 10 are properly screwed in, by the prior art sealing lugs 413, 414.

Fig. 5 is a partial sectional view of directly attaching the filter 403 to the fan module 401 in accordance with the invention; connection. The purpose of the cylindrical portion 407 is to direct air to the impeller in the fan module or similar pumping member which, when rotated by an electric motor 20, pumps air into the face of the ventilator. The combination between the fan module and the: V. filter, in which the filter retaining neck 303 is inserted; over the cylindrical portion 407, as such, would require no other parts. However, for the stability of the joint, * 1, 1, it is preferable that the arrangement further comprises a support member * * ^ 501 having an internal thread 502 suitable for the external thread of the filter retaining collar and can be secured to the fan module 401 by a similar 4 with reference to the attachment of the suction duct module 402 to the fan section 401. It is clear that the prior art: * ·· seal could also be added to the arrangement of Fig. 5, for example by forming the cylindrical: T: 30 portion of the fan module 401 to the left end) the platform against which the prior art sealing ring would be positioned.

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Because in the arrangement of the invention, sealing does not occur at the outermost end of the filter clamping neck, and since the seal between the filter and the other respirator 35 is not dependent on axial movement of the filter clamping neck internal threads for attaching the filter may be shaped in a manner different from prior art 6 117161. The aforementioned state-of-the-art standard DIN 3182 states that the thread of the clamping neck must remain visible even when the filter is properly screwed in. In the arrangement according to the invention, this need not be the case, but the filter can be rotated so far that the entire fastening neck 5 disappears from the visible recess in which the wall has internal threads.

A variant of the latter principle can be illustrated in Fig. 6, wherein a separate annular sealing portion 602 is formed in the support portion 601 (or other similar portion to which the filter is threaded) when the filter 10 403 is fully screwed in, sealing portion 602 depresses filter surface 603 facing the part of the ventilator to which the filter is attached. Such stiffening effectively prevents the accumulation of dirt and dust in the filter neck area. Figure 6 also shows how the prior art seal ring 320 is inserted into an arrangement where the filter is directly connected to the fan-15 module.

The body of the filters is usually injection-molded polypropylene.

In a modular blower device, the blade module body material is typically glass fiber reinforced injection-molded polypropylene. The suction duct module may be of any of a more flexible material, such as polyurethane, molded for example; why casting. The benefits of selecting materials are described, for example, in the # #

; in the Finnish patent application number 972931 of the same applicant. Standard DIN

. ,,, · 3182, however, requires that the thread whereby the filter attaches to some other • part of the ventilator be filled, e.g. certain rigidity requirements. Because of this, * ·· * 25 suction duct module * i made of soft material such as polyurethane had to be fitted with a threaded insert, * for example, injection-molded polypropylene. According to the present invention, the sealing in the filter mounting does not depend on the stiffness of the thread, so that the use of * ·: * ·· inserts can be at least partially dispensed with. For example, in the arrangement 30 shown in Figure 5, the support member 501 may be entirely of polyurethane. Plastic parts made entirely of the same material are advantageous in both manufacturing technology and recyclability.

The invention may be modified in various ways without departing from the scope of the following 35 claims. For example, the invention does not require the inside surface of the filter neck to have a straight circular cylinder, but may be slightly conical so that the inside diameter of the neck is at its largest at the outermost end of the neck and decreases toward the inner end of the neck. This provides the advantage that the filter is easier to control. On the other hand, at the same time, some of the advantageous features of the invention are lost because the conical clamping neck is sealed against the O-ring on the surface of the cylindrical portion entering it only when the filter 5 is properly screwed in. Also, the cylindrical portion in the suction duct module or fan module which protrudes into the filter mounting neck when the filter is mounted may be of a non-cylindrical shape: the invention only requires that a sufficient proportion thereof be accommodated within the filter mounting neck. The cylindrical portion 10 in question is called cylindrical only to have a certain consistent and unambiguous designation. The invention also does not require that the outer surface of the filter neck has threads according to DIN 3182 or that the outer surface of the neck has no threads, but since the filter production lines are typically provided with threads on the outer surface of the filter neck. existence as in prior art arrangements.

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Claims (8)

117161 An arrangement for attaching a filter (301, 403, 404) to a breathing apparatus, wherein the sequential filter 5 comprises a clamping neck (303) having an external threaded surface and a smooth inner surface, the first portion (302, 402, 401) of the breathing apparatus 306,407), which is smooth, comprises 10 internal threads (305, 502) corresponding to the threaded outer surface of the filter attachment neck for attaching the filter (301, 403, 404) directly or through a second portion (501, 601) to the first portion (302,402,401); the arrangement comprising means (308, 411, 412, 410) for forming a sealing point between the filter (301, 403, 404) and the first part (302, 402, 401) of the ventilator 15; characterized in that - the outer diameter of the smooth cylindrical portion (306, 407) in the first portion (302, 402, 401) of the breathing apparatus is smaller than the inside diameter of the fastening neck (303) and the means (308, 411, 412); 410) for forming a sealing point is arranged to provide a sealing point between a smooth cylindrical outer surface portion (306, 407) in the first portion of said breathing apparatus. An arrangement according to claim 1, characterized in that it comprises, in said first part of the ventilator, an internal thread (305) which is concentric with said cylindrical part (306) and to which said outer thread is mechanically fit. ♦ * • * * Arrangemang enligt patent krav 1, a rotating device for detergent insertion of a respirator (305) and a respirator for a cylindrical respirator (306) and an operation of the passar in mechanism. Arrangemang enligt patentkrav 1, a translation technique for att det deteffer in in gänga (502) i en spec andra del (501, 601) av respiratom, i flaunting this yttre gänga mechanic passar in. An arrangement according to claim 1, characterized in that it comprises an internal thread (502) in a certain second part (501, 601) of the breathing device, to which: V: said external thread is mechanically fit. An arrangement according to claim 3, characterized in that it further comprises means for securing said first part (401) and said second part (501, 601) in a position in which said the inner thread (502) and said cylindrical portion (407) being disposed centrally relative to each other. 117161 4. Arrangemang enligt patent krav 3, a translation technique for the att det dessutom innefattar 15 organ för att fåsta första del (401) och nämnda andra del (501, 601) vidandra to för, gärnda inre gänga (502) och nämnda cyl. (407) and placerade inbördes concentriskt. Arrangemang enligt patent krav 4, a rotary link module (401) for the respiratory module (401) and the modular interface (501, 601). ·· i: ·: • * «* An arrangement according to claim 4, characterized in that said first part is a fan module (401) of a modular blower part of the ventilator and said second part is a support part (501,601) to be attached thereto. Arrangement according to Claim 2 or 3, characterized in that said external thread is a thread according to DIN 3182. A method for forming a sealing point (308, 411, 412, 410) between a filter (301, 403, 404) and a cylindrical portion (306, 407) in a first portion (302, 402, 401) of a ventilator, for attaching a filter to a first portion of a ventilator. (302, 402, 401) by means of a threaded fastening, characterized in that the sealing point (308, 411, 412, 410) is formed by a smooth outer surface of the cylindrical portion (306, 407) in the first portion (302, 401, 402) of the breathing apparatus and ) between the smooth inner surface. 15 Method according to claim 7, characterized in that it further supports the attachment between the filter (403) and said first part by twisting the threads (304) on the outer surface of said attachment collar to mechanically corresponding inner threads (305), 20 M ». • f Vj 1. Arrangemang för att fästa ett filter (301, 403, 404) vid en respirator, i whistle *: ··: arrangemang ·; · 25 - filter innefattar en fastsättningshals (303), med en gängad yttre yta och en slät inre - respiratoms första del (302, 402,401) innefattar et parti (306,407) med formen av yttre ytan av en cylinder, som är slät,. - arrangemanget innefattar en inre gänga (305, 502) som motsvarar den gängade \\ V 30 yttre ytan av filtrets fastsättningshals för att fästa filtret (301, 403, 404) direct eller * ·; · via en speciell andra del (501, 601) ) account respiratoms första del (302, 402, 401) och: V: - arrangemanget innefattar organ (308, 411, 412, 410) för att bilda et tëstningst: ***: mellan filtret (301,403,404) och respiratoms första del (302,402,401) ); ·· • Λ kännetecknat av att * * «\ \ 35 - diametem hos det släta partiet (306, 407) med formen av yttre ytan av en cylinder i" · respiratory första del (302, 402, 401) är mindre än fastsättningshalsens ( 303) inre diameter och 10 117161 - organ (308, 411, 412, 410) för att bilda tätningsstalle and anordnade att bilda det släta partiet (306, 407) med formen av yttre ytan av en cylinder i nämnda respirators första del (302,402,401) och den inre ytan av nämnda fastsättningshals 5 6. Arrangemang enligt patentkrav 2 eller 3, kännetecknat av att nämnda yttre *: ··: gänga en gänga enligt DIN 3182 standard. ... f 25 • \ e 7. Förfarande för att picture that the filter (308, 411, 412, 410) has a filter (301, 403, 404) and a cylindrical filter (306, 407) and a respirator (302, 402, 401) and filters the filter. respiratoms första del (302, 402, 401) med gängfäst- * Ning, kännetecknat av att tätningsstället (308, 411, 412, 410) picture mellan den 30 släta yttre ytan av det cylindriska partiet (306, 407) i respiratoms första del ( 302, • · * ··· * 401,402) och den släta inre ytan av fastsättningshalsen (303) i filtret. »: *: *: ***: 8. Förfarande enligt patentkrav 7, kännetecknat av att dessutom stöds infästnin- · <· .Λ gen mellan filtret (403) och nämnda första del genom att vrida gängoma (304) i yttre \\ 35 ytan av these fastsättningshals mechanics i motsvarande inre gängor (305). • «f • ·» t ·