Ventilation and filtration device for the purification of air within the closed protected space of a facility

Abstract

A filtration and ventilation device for the purification of air within a closed protected space of a facility according to the invention is characterized in that at the outlet of the filter-absorber (1), a self-acting check valve (2) is situated to ensure structurally determined unidirectional flow of air through the filter-absorber into the protected space or the facility and shut off uncontrolled backflow of contaminated / damp air to the filter-absorber. The implemented solution is aimed at the protection of the filter-absorber (1) installed in the device against the destructive impact of the external environment and the resulting extension of the useful life of the filter-absorber.

Description

[0001] Ventilation and filtration device for the purification of air within the closed protected space of a facility

[0002] The invention relates to a ventilation and filtration device for the purification of air within a closed protected space of a facility, said device being equipped with an air filter-absorber outlet check valve providing protection against the undesirable backflow of air to the filterabsorber. The air filter-absorber outlet check valve is designed to protect the filtration and ventilation device equipped with said filter-absorber during its storage and use, including particularly against the undesirable impact of airborne impurities and moisture on the filterabsorber.

[0003] Various types of ventilation and filtration / ventilation devices are known from the prior art and intended for supplying the closed protected spaces of indoor facilities with purified air or for purifying the air within these spaces of various types of mechanical and industrial pollutants.

[0004] Various types of filtration and ventilation devices are known in military art to protect the supply of purified breathable air within the protected spaces of stationary facilities (such as shelters or command posts) as well as mobile facilities (such as combat vehicles, special vehicle bodies, cabins, and containers). The aforementioned devices, constructed as collective protection systems for people outside or inside facilities, operate by collecting air from the environment and, after passing it through appropriate filters, feeding it into the protected spaces. The devices operate in the following modes: pure ventilation - protection against the inflow of mechanically contaminated external air (dusts, natural smoke particulates) and / or filtrationventilation, involving additional protection against the inflow of air that has been contaminated mechanically (finer dusts, radioactive dusts, aerosols, vapors), chemically (vapors and gases of chemical warfare agents) and biologically (viruses, bacteria). The operating mode of these devices is switched mechanically by means of air valves, with the use of various types of actuators, or by manual force. Said devices are equipped with electrical / electronic control systems to facilitate the supply of purified air according to appropriately predefined / preset parameters, including efficiency, overpressure, operation mode switching condition, cooperation with pollution detection devices, etc.

[0005] The operation of filtration and ventilation devices commonly used for collective protection purposes, differing in the methods of ensuring the supply of purified air to the protected space, are presented for standalone system and facility-mounted external units in block diagrams in Figs, l.a and l.b.

[0006] In the case of the filtration ventilation device FVD shown in Fig. 1.a, the polluted external air is collected from the environment by the pre-filter PF as a result of underpressure generated by the air turbine AT and further fed through three-way valve TWV - depending on its setting - to the protected space of the facility F. In the pure ventilation (PV) mode, air pre-pureed of mechanical impurities on the filter PF is fed directly through the air duct AV to the protected space of the facility F. In the filtration-ventilation (FW) mode, the additionally passes additionally through the filter absorber FA, where it is additionally purified of minor mechanical impurities (including radioactive ones), as well as chemical and biological impurities, and further fed directly through the additional air duct AF to the protected space of the facility F. At the same time, both in the CW and the FW mode, no drying is applied to the passing air. In this embodiment, when the filtration and ventilation device FVD is non- operationally stored within the facility F or operated in the pure ventilation mode PV, the three- way valve TWV is set in the position tightly closing the air supply to the filter-absorber FA while on the side of the protected space, penetration of contaminated / damp air to the filterabsorber FA is tightly shielded by the protective cap PC. In the pure ventilation mode PV, the filter-absorber FA is also effectively protected against the inflow of contaminated / damp air from both sides as specified above. A disadvantage of this solution consists in the requirement to provide physical access to the protective cap PC and the need to remove this cap when switching the device to work in the filtration-ventilation mode FV. Another disadvantage consists in the use of structurally complex dual-channel (D V and DF) supply of purified to the protected space of facility F, where the required free space is not always available.

[0007] In the filtration and ventilation device FVD in the variant shown in Fig. l.b, a common, simplified design of purified air being supplied to the protected space of the facility F via a single air duct DA has been used. In this case, contaminated outside air is also taken collected the environment via the pre-filter PF as the result of underpressure generated by the air turbine AT and is fed further through the three-way valve TWV, depending on its setting, to the protected space of the facility F. In pure ventilation mode PV setting of the three-way valve TWV, non-dried air pre-pureed from mechanical impurities on the pre-filter PF, is fed through the air duct DF and further through the T-connector TC and the air duct DA to the protected space of the facility F. However, in this case, some of the contaminated (just pre-pureed) and damp air flows back (as the result of fluctuations of the overpressure of air in the protected space) through the T-connector and the filtration duct DF to the open air outlet of the filter absorber FA. Taking into account that the pure ventilation mode PV is the most common operational mode of the filtration and ventilation device (i.e. operated for longest durations in normal, i.e. uncontaminated, environmental conditions), the harmfill long-term impact of the backflow of contaminated / damp air on the filter-absorber cannot be disregarded.

[0008] When the device is non-operationally stored within the facility set F, the three-way valve TWV is always set in the position tightly closing the supply of external air to the filter-absorber FA. A disadvantage of this solution also consists in the fact that the filter-absorber FA air outlet is not protected against the backflow of contaminated / damp air (via the T-connector TC) from the protected space of the facility F through air duct DA (as the result of fluctuations in the overpressure of air within the protected space) as well through air duct DV (as the result of fluctuations in the outside air pressure outside). The tight closure of the air duct DA outlet using the protective cap PC (or shut-off valve) on the side of the protected space of the facility F does not protect the filter-absorber FA against the ingress of damp external air through the air duct DV from the pre filter PF during non-operational storage. This is a significant problem that can lead to degradation of filter-absorbers, especially following long-term (multi-year) non- operational storage of filtration and ventilation devices within the facilities.

[0009] For the operation of the filtration- ventilation device FVD in the filtration- ventilation mode FV, the three-way valve TWV is set in the FV position to open the delivery of external air to the filter-absorber FA. The air then passes through the filter-absorber FA, where it is additionally purified of minor mechanical impurities as well as chemical and biological impurities and is fed through the air duct DF to the T-connector TC and further through the air duct DA to the protected space of the facility F. This is the basic variant of the use of the filtration and ventilation device as intended (when used under air contamination conditions), wherein the filter-absorber is subject to all possible environmental exposures. However, this is intended to be a relatively short period; after leaving the contaminated zone the filtration and ventilation device should be deactivated (decontaminated, disinfected) and the filter-absorber should be replaced.

[0010] The design of the filtration and ventilation devices FVD presented above, consisting of separate units being located outside the facility F, facilitates the process of replacing filter cartridges of the pre-filter PF as well as filter-absorber FA, particularly after exposure to external contamination has come to an end. In other embodiments of the design, the listed components of FVDs can be installed inside the facility F either outside the protected space, inside the protected space or partially outside and partially inside the protected space. In any case, however, the basic principle of operation of the filtration and ventilation devices FVD remains the same as described above.

[0011] Despite the availability of numerous different solutions for the filtration and ventilation devices FVD, the designs of these devices do not provide for the possibility of protecting their filter-absorbers FA against the backflow of contaminated / damp air. Filter-absorbers FA with exemplary external structure as shown in Fig. 2 are known in military art, with rated clean air efficiencies of 100, 200 and 300 m3 / h, respectively. Filter-absorbers FP (1) usually consist of metal housing with an additional layer of nonwoven fine-filter fabric to retain minor mechanical impurities and a layer of activated carbon to retain chemical and biological impurities. The activated carbon layer of the filter-absorber FA as a standalone subunit (as a replaceable operational component) is protected against degradation by contaminants and moisture contained in the air. In this case, when the filter-absorber FA is stored in an non-operational mode, the inlet and outlet of air of the filter-absorber FA are tightly closed with lids preventing the filter-absorbed against the ingress of contaminated and damp outside air. On the other hand, when the filter-absorber FA is installed within the filtration-ventilation device FVD (Fig. 3), the three-way valve TWV is set in the position tightly closing the air inlet to the filter-absorber while filter-absorber remains unprotected on the side of the air outlet. This results in contaminated and damp air entering the filter-absorber FA as described above, and consequently in accelerated degradation of the activated carbon layer and reduction in the time of possible effective use of the filter-absorber.

[0012] Various types of check valves to ensure airflow in only one direction are also known in the art. On the basis of closure design, check valves are categorized into poppet valves, ball valves, plate valves, membrane valves, and flap valves. On the basis of operation mode, the valves are categorized into load valves - closed upon no pressure difference, and unloaded valves - closed by the difference in flows and pressures. For structural and functional reasons, the optimum solution for the inventive protection of filter-absorbers FA against the backflow of contaminated / damp air appears to consist in self-acting, normally closed membrane / flap valves switching between the closed and the open state depending on the sign of the difference of pressures on both sides of the valve.

[0013] For example, a filtration and ventilation device comprising two parallel filtration and ventilation sets operating in an alternating fashion, coupled together and supplying purified air to the protected space of the facility through a common duct is known from patent applications P-365760 and PL-204155 Bl.

[0014] The utility model PL-064292 discloses a filtration and ventilation device, particularly for use in combat vehicles, comprising air purification units and air forcing blower units connected by air ducts, featuring a housing with cyclone blowpipes connected to a dual-position control valve having one outlet connected directly to a manifold connected to the vehicle cabin and the other outlet connected to the manifold through a filter-absorber.

[0015] Various structural and functional solutions of filtration and ventilation devices FVD intended for collective protection, including in combat vehicles, are also known from other applications of inventions. The above solutions do not provide for the use of a check valve CV ZZ at the outlet of air from the filter-absorber FA.

[0016] Considering the above, it is advisable to provide structural protection of the air outlet of filter-absorber FA against the backflow of contaminated / damp air using the check valve CV as part of the filtration and ventilation devices FVD.

[0017] The invention is aimed at the development of a filtration-ventilation device FVD effectively securing unilateral flow of air through the filter-absorber FA.

[0018] The filtration and ventilation device FVD complete with a check valve CV on the air outlet of filter-absorber FA protects the filter-absorber during operation of the device against environmental exposures in the form of uncontrolled backflow of contaminated / damp air resulting in degradation of the internal structure of the filter-absorber.

[0019] The filtration and ventilation device FVD complete with a check valve CV on the air outlet of filter-absorber FA extends the usefill life of the filter-absorber installed in the device.

[0020] Filtration and ventilation device according to the invention for the purification of air within a closed protected space in indoor facility comprising a housing in which a pre-filter PF, an air turbine AT, a three-way valve TWV, a filter-absorber FA and air supply ducts DV, DF and DA are installed is characterized in that at the outlet of the filter-absorber, a self-acting check valve is situated to ensure unidirectional flow of air into the protected space and shutting off uncontrolled backflow of contaminated / damp air to the filter-absorber.

[0021] Preferably, the check valve is mounted on the housing at the air outlet of the filter-absorber and is connected to said housing by means of a flexible gasket and metallic face using screw fasteners. Preferably, the check valve follows a flap-plate design wherein the flexible pressure flap is a part of the flexible gasket.

[0022] Preferably, the check valve is installed on the extension of the air outlet stub of the filterabsorber and air duct section terminated, in addition to check valve, by another air duct section.

[0023] The filtration and ventilation device FVD fur the purification of air within the closed protected space of a facility, complete with a check valve CV on the air outlet of filter-absorber FA, protects the filter-absorber during operation of the device against environmental exposures in the form of uncontrolled backflow of contaminated / damp air resulting in degradation of the internal structure of the filter-absorber, thus extending the useful life of the filter-absorber installed in the device.

[0024] Embodiments of the ventilation device for the purification of air within closed protected space of a facility are shown in the figures, wherein FIGS, l.a-b show the block diagrams of the filtration-ventilation device according to the invention; FIG. 2 is a perspective view of a filter-absorber with a check valve mounted to the housing of said filter-absorber; FIG. 3 is a general view of the same filter-absorber with a check valve mounted in orthogonal projections; FIG. 4 is an orthogonal projection of the vertical longitudinal section A-A of the same filterabsorber with a flap-plate check valve mounted thereto in open position; FIG. 5 is an orthogonal projection of the horizontal longitudinal section B-B of same filter-absorber with an open flapplate check valve mounted thereto in open position; FIG. 6 is an orthogonal projection of the vertical longitudinal section A-A of the same filter-absorber with a closed flap-plate check valve mounted thereto in closed position; FIG. 7 is a perspective view of the filter-absorber with the check valve being mounted thereto in another way constituting another embodiment of the filtration-ventilation device; FIG. 8 is a perspective view of the filter-absorber in yet another variant of check valve being incorporated within the structure; FIG. 9 is an orthogonal projection of the vertical longitudinal section of the same filter-absorber with a flap-plate check valve mounted thereto; and FIG. 10 is an orthogonal projection of the vertical longitudinal section of the same filter-absorber with a standard poppet check valve mounted thereto.

[0025] In an embodiment, the filtration and ventilation device for the purification of air in a closed protected space - presented in the form of a block diagram in Fig. l.a - consists of an air prefilter PF, an air turbine AT, a three-way valve TWV, a filter-absorber FA, an additional check valve CV and air supply ducts DV, DF, and DA. This is the basic functional system of the filtration and ventilation device FVD, with a simplified design for the supply of purified air to the protected space of the facility F via a single air duct DA as well as via the additional check valve CV structurally integrated with the filter-absorber FA within the FVD system. During the operation of the filtration and ventilation device FVD contaminated and damp outside air is also taken collected the environment via the pre-filter PF as the result of underpressure generated by the air turbine AT and is fed further through the three-way valve TWV, depending on its setting, to the protected space of the facility F. In pure ventilation mode PV setting of the three-way valve TWV, non-dried air pre-pureed from mechanical impurities on the pre-filter PF, is fed through the air duct DF and further through the T-connector TC and the air duct DA to the protected space of the facility F. However, in this case, some of the contaminated (just pre-pureed on the prefilter PF) and damp air flows back (as the result of fluctuations of the overpressure of air in the protected space) along air duct DA through the T- connector and further via the filtration duct DF to check valve CV. Normally in closed position, check valve CV does not allow contaminated / damp air to flow back into the structural filterabsorber FA air outlet, thus protecting the filter-absorber against the possibly harmful longterm effects of this air. This is particularly important since pure ventilation mode PV is the most common operational mode of the filtration and ventilation device (i.e. operated for longest durations in normal, i.e. uncontaminated, environmental conditions).

[0026] Likewise, when the FWD device is stored in the facility F, the three-way valve TWV is always set in the position tightly closing the supply of external air to the filter-absorber FA, and the air outlet of the filter-absorber FA is protected against the backflow of contaminated / damp air (via the T-connector TC) from the protected space of the facility F through air duct DA (as the result of fluctuations in the overpressure of air within the protected space) as well through air duct DV (as the result of fluctuations in the outside air pressure outside) by the normally closed check valve CV. Thus, the above system effectively protects the filter-absorber FA during non-operational storage against the ingress of contaminated / damp air both from the protected area within the facility and the outside environment. As the result, no degradation of filter-absorbers occurs, especially upon long-term (multi-year) non-operational storage of filtration and ventilation devices within the facilities.

[0027] For the operation of the filtration- ventilation device FVD in the filtration- ventilation mode FV, the three-way valve TWV is set in the FV position to open the delivery of external air to the filter-absorber FA. The air then passes through the filter-absorber FA, where it is additionally purified of minor mechanical impurities as well as chemical and biological impurities and through the normally closed check valve CV (which, in this case, opens up as the result of the difference in pressure on both sides of the valve) and is fed through the air duct DF to the T-connector TC and further through the air duct DA to the protected space of the facility F. This is the basic variant of the use of the filtration and ventilation device as intended (when used under air contamination conditions), wherein the filter-absorber is subject to all possible environmental exposures. However, this is intended to be a relatively short period; after leaving the contaminated zone the filtration and ventilation device should be decontaminated and the filter-absorber should be replaced.

[0028] Another embodiment of the filtration and ventilation device for the purification of air in a closed protected space is presented in the form of a block diagram in Fig. l.b and consists of an air prefilter PF, an air turbine AT, a three-way valve TWV, a filter-absorber FA, an additional check valve CV and air supply ducts DV, DF, and DA. This is the basic functional system of the filtration and ventilation device FVD, with a simplified design for the supply of purified air to the protected space of the facility F via a single air duct DA as well as via the additional check valve CV provided with the FVD system as a separate subassembly mounted into the air duct DF - without structural integration with the filter-absorber FA. Practical applicability of such a solution for check valve installation may be determined by structural considerations. The operation of the above filtration- ventilation device FVD featuring the check valve CV air in the pure ventilation mode PV, during non-operational storage and in the filtration- ventilation mode FV is the same as in the first example.

[0029] Fig. 2 is a perspective view of an embodiment including filter-absorber FA 1 with the air check valve CV 2 within a functional system of a filtration and ventilation device FVD according to the block diagram in Fig. l.a, delivered in a structurally compact form ready for installation in the device. The flexible air duct DF 3 is installed and sealed at the outlet stub of check valve CV 2 using hose clamp 3. a.

[0030] Fig. 3 is a general view of the filter-absorber FA 1 of Fig. 2 with the air check valve CV 2 mounted thereto and fitted with an elastic air duct DA 3 in orthogonal projections. The check valve CV (2) consists of a housing (2.a) attached to the filter-absorber using fasteners in the form of screws (2.f) and washers (2.g). The screws are complete with holes (2.h) holes for the wire protecting against unscrewing and being threaded therethrough and a seal being placed on the connection. The flexible air duct DF 3 is installed and sealed at the outlet stub of check valve CV 2 using hose clamp 3. a. Fig. 4 is an orthogonal projection of the vertical longitudinal section A-A of the filterabsorber FP 1 of Fig. 2 with a flap-plate check valve CV 2 mounted thereto in closed position and fitted with an elastic air duct DA 3. The check valve (CV) 2 is screwed to the filter-absorber (FA) 1 and sealed at the direct contact point with the filter-absorber using a flexible gasket 2.e. This valve has a flap-plate design wherein the flexible pressure flap 2.c is structurally separated (cut out) from the flexible flat plate 2.d. The flap 2.c is closed automatically by elastic forces to seal to the rigid flat metal face 2.b as shown in the view. The check valve (CV) 2 - screwed to the filter-absorber (FA) 1 using fasteners 2.f and 2.g, is sealed along the perimeter of the direct contact point with the rigid metal face 2.b by means of a flexible flat plate 2.d (as being in structural unity with the pressure flap 2.c). Any backflow of air (contaminated and damp) from the filtration-ventilation device FVD results in overpressure within the flexible air duct (DA) 3 to additionally seal flap 2.c onto the rigid flat metal face (2.b), thus blocking the ingress of this air to the filter-absorber (FA) 1.

[0031] Fig. 5 is an orthogonal projection of the vertical longitudinal section A-A of the filterabsorber FA 1 of Fig. 2 with an open flap-plate check valve CV 2 mounted thereto in open position. The pressure flap 2.c, normally closed, opens up spontaneously as show under excessive pressure of air on the side of the filter-absorber FA (1). The resulting large flow area of the open check valve (CV) 2 does not pose significant restriction (resistance) to the flow of compressed air filtered on the filter-absorber (FA) 1. The filtered air then enters the system further through the flexible air duct (DA) 3.

[0032] Fig. 6 is an orthogonal projection of the horizontal longitudinal section B-B of the filterabsorber FA 1 of Fig. 2 with an open flap-plate check valve CV 2 mounted thereto in open position. The pressure flap 2.c, normally closed, opens up spontaneously as show under excessive pressure of air on the side of the filter-absorber FA (1). The large flow area of the open check valve (CV) 2 obtained by means of the presented open apertures of the rigid flat metal face (2.b) does not pose significant restriction (resistance) to the flow of compressed air filtered on the filter-absorber (FA) 1.

[0033] Fig. 7 is a perspective view of an embodiment including filter-absorber FA 1 with the air check valve CV 2 inversely mounted (along the axis of the filter-absorber) at the outlet stub to form a functional system of a filtration and ventilation device FVD according to the block diagram in Fig. l.a, delivered in a structurally integrated form ready for installation in the device. The flexible air duct DF 3 is installed and sealed at the outlet stub of check valve CV 2 using hose clamp 3. a. Fig. 8 is a perspective view of an embodiment including filter-absorber FA 1 with the air check valve CV 2 mounted in a different fashion (perpendicular to the filter-absorber) to form a functional system of a filtration and ventilation device FVD according to the block diagram in Fig. l.a, delivered in a structurally integrated form ready for installation in the device. The flexible air duct DF 3 is installed and sealed at the outlet stub of check valve CV 2 using hose clamp 3. a.

[0034] Fig. 9 is an orthogonal projection / longitudinal cross-section of an embodiment including the filter-absorber FA 1 with the check valve CV 5 having a flap-plate design (similar to the above). The check valve CV is connected to the filter-absorber FA and the rest of the system using sections of flexible air duct PF 3.b and 3.c, mounted and sealed onto the outlet stub (elbow) 4 and the stubs of the check valve CV 5 using hose clamps 3. a.

[0035] Fig. 10 is an orthogonal projection / longitudinal cross-section of an embodiment including the filter-absorber FA 1 with the check valve CV 6 having a poppet design within a functional system of a filtration and ventilation device FVD according to the block diagram in Fig. l.b. The check valve CV is connected to the filter-absorber FA and the rest of the system using sections of flexible air duct PF 3.b and 3.c, mounted and sealed onto the outlet stub (elbow) 4 and the stubs of the check valve CV 6 using hose clamps 3. a.

[0036] The use of the filtration and ventilation device FVD complete with a check valve CV on the air outlet of filter-absorber FA as in the presented embodiments protects the filter-absorber FA during operation of the device - including during non-operational storage and during operation in the pure ventilation mode - against environmental exposures in the form of uncontrolled backflow of contaminated / damp air resulting in degradation of the internal structure of the filter-absorber.

[0037] Implementation of the filtration and ventilation device FVD complete with a check valve CV on the air outlet of filter-absorber FA extends the useful life of the filter-absorber installed in the device.

Claims

Claims1. Filtration and ventilation device for the purification of air within a closed protected space in indoor facility, comprising a housing in which a pre-filter PF, an air turbine AT, a three- way valve TWV, a filter-absorber FA and air supply ducts DV, DF and DA are installed, characterized in that at the outlet of the filter-absorber (1), a self-acting check valve (2) is situated to ensure unidirectional flow of air into the protected space and shut off uncontrolled backflow of contaminated / damp air to the filter-absorber (1).

2. Device according to claim 1 characterized in that the check valve (2) is mounted on the housing at the air outlet of the filter-absorber (1) and is connected to said housing by means of a flexible gasket (2.e) and metallic face (2.b) using screw fasteners (2.f).

3. Device according to claim 1 characterized in that the check valve (2) follows a flap-plate design wherein the flexible pressure flap (2.c) is a part of the flexible gasket (2.d).

4. Device according to claim 1 characterized in that the check valve (2) is installed on an extension of the air outlet stub (4) of the filter-absorber (1) and air duct section (3.b) terminated, in addition to check valve (2), by air duct section (3.c).

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