FILTER UNIT FOR A COMPRESSOR

Description

[0001] The present invention relates to a compressor equipped with a filter unit and to a method for compressing and filling breathing air by means of such a compressor.

[0002] While strict regulations regarding the quality and maximum permissible contaminants already exist for the compression and filling of gases, especially breathing air, such as the breathing air standard EN12021:2014-07, which stipulates that all contaminants must be less than one-tenth of the national 8-hour exposure limits, there has recently been a desire or need to inactivate any viruses that may be present in the gas to be compressed before it is compressed and filled. It is therefore understood that, in the context of this description, the term "gas" should always include gas mixtures.

[0003] Due to their structure and size, such inactivation of viruses is, according to current knowledge, only possible using heat, pressure, suitable chemicals and UV radiation.

[0004] When using heat, a residence time of 8 minutes at temperatures above 120°C is required. While such conditions could be created in the intake area of ​​a compressor, the gas to be compressed would then have to be cooled again, which would be costly, as conventional compressors have a maximum intake temperature of approximately 45°C, which must not be exceeded.

[0005] On the other hand, while the temperature in the compressor itself can sometimes exceed 200°C, the gas's residence time in this state is usually only a few seconds, so reliable inactivation of viruses is not guaranteed. It should also be considered that heating already pressurized containers results in a significant additional pressure increase, which could result in the container being destroyed or requiring a higher pressure design, which would significantly increase costs.

[0006] Finally, an increase in temperature before filling the container would result in a significant drop in pressure in the container being filled after the gas has cooled, making it impossible to store the intended gas volume. Thus, there is no way to achieve sufficient heating of the gas being filled at any point during the compression and filling process in an efficient and economically viable manner.

[0007] Similarly, inactivation of viruses by means of pressure or chemicals is not feasible because, on the one hand, pressures of over 4000 bar would be necessary, which also cannot be realized in an economically viable manner, and, on the other hand, the use of virucidal disinfectants is not feasible for many processes, especially in the case of compressing and filling breathing air.

[0008] In this connection, JP H02 23278 A discloses a filter unit for a compressor, which comprises a housing, a pre-filter, an ultraviolet irradiation unit, and a ballast for controlling the irradiation unit. For the sake of completeness, reference is also made to CN 209 839 649 U, as well as to JP 3 009261 U, which specifically deals with the wiring of a compressor device, including its motor and a UV lamp.

[0009] It is therefore the object of the present invention to provide a compressor with which viruses contained in the gas to be compressed can be inactivated in a reliable and efficient manner.

[0010] For this purpose, the filter unit for the compressor according to the invention comprises a housing with an inlet and an outlet for gas to be compressed, a particle pre-filter arranged downstream of the inlet in the flow direction of the gas to be compressed, an ultraviolet irradiation unit arranged downstream of the particle pre-filter in the flow direction of the gas to be compressed, which is configured to emit ultraviolet light, and a ballast configured and arranged to control the ultraviolet irradiation unit. The filter unit is designed such that gas to be compressed supplied at the inlet first passes through the particle pre-filter, is then irradiated by the ultraviolet irradiation unit, and can finally be supplied to the compressor through the outlet.

[0011] It is therefore the merit of the present inventors to have recognized that the filter unit can free the gas from active viruses even before the actual compression, whereby the particle pre-filter protects the ultraviolet irradiation unit from contamination and a consequent deterioration of its efficiency and inactivation rate.

[0012] The ballast is in turn responsible for supplying the irradiation unit with electrical energy and, depending on its design, can be designed to supply an increased current during a switch-on process and then a substantially constant current.

[0013] Furthermore, the filter unit described here is suitable for both mobile and stationary compressor systems, as it is installed in the intake line at atmospheric level. This also makes the unit according to the invention particularly suitable as a retrofit solution, as it can be operated completely independently and only requires a separate power supply for the ballast and the irradiation unit. Furthermore, it should be noted that although this description primarily focuses on the inactivation of viruses in the gas to be compressed, the filter unit according to the invention can also be used effectively to combat bacteria, spores, etc.

[0014] In an advantageous embodiment, the housing of the filter unit in the area of ​​the ultraviolet irradiation unit can be made at least partially, preferably entirely, particularly on its interior, of anodized aluminum. In contrast to, for example, stainless steel, anodized aluminum exhibits excellent reflection properties in the relevant ultraviolet wavelength range, which increases the efficiency of the irradiation. Furthermore, the absorption of radiation in stainless steel could lead to undesirable increased heating of the housing. In particular, the housing could be made at least partially from a type of aluminum tube that is commonly used in the large-scale production of gas cartridges.A cost-effective supply of this critical component is therefore ensured, with cartridge tubes with article numbers 61089, 62333 and 60174 being used in particular.

[0015] Furthermore, the housing in the area of ​​the ultraviolet irradiation unit can be elongated, particularly cylindrical, for example circularly cylindrical. This not only creates a suitable receiving space for the irradiation unit, which is usually also elongated, but also increases the residence time of the gas in the effective irradiation area, thus ensuring the efficiency of the filter unit. Furthermore, a circular-cylindrical shape of the housing in the area of ​​the ultraviolet irradiation unit ensures that a laminar gas flow is generated along the irradiation unit, in which the gas is always guided past it at a well-defined distance. Furthermore, disadvantageous flow characteristics within the housing that could be caused by undercuts or similar features are avoided.

[0016] A further measure to increase the efficiency of the unit can consist of further configuring the ballast to adapt the control of the ultraviolet irradiation unit to an ambient temperature and / or a temperature of the gas to be compressed, which can be entered by a user using an input unit or detected by a suitably arranged sensor unit. This development is based on the fact that the inactivation rate is usually temperature-dependent, so that the ultraviolet irradiation unit must be designed to be at least powerful enough to still achieve the desired inactivation rate in the least effective temperature range. For example, its radiation output could be regulated down by the ballast at higher temperatures.The input unit and / or the sensor unit used may be of any suitable known types of such units and may be arranged accordingly and operatively coupled to the ballast.

[0017] As a safety measure and to prevent insufficiently treated gas from being compressed and / or bottled in the event of a failure or other problem with the ultraviolet irradiation unit, the filter unit according to the invention can further comprise a monitoring unit configured to monitor the correct operation of the ultraviolet irradiation unit. This can include, among other things, monitoring the electrical properties of the ultraviolet irradiation unit using suitable means, for example, an interruption in the supply circuit, a failure of the irradiation unit during operation, a short circuit or breakage of radiator electrodes, a drop below the minimum permissible mains voltage, or an exceedance of the maximum voltage applied to the irradiation unit.Furthermore, a sensor for ultraviolet radiation could be provided within the housing, which emits a corresponding signal when the radiation intensity is below a predetermined threshold.

[0018] One possibility for further processing incorrect operation of the ultraviolet irradiation unit detected by the monitoring unit may be for the filter unit to further comprise a notification unit that is operatively coupled to the monitoring unit and configured to issue a notification upon detection of a deviation from the correct operation of the ultraviolet irradiation unit. This may include an indicator device such as a display or simply a warning light, or alternatively or additionally, an acoustic signaling unit. Furthermore, in addition to the notification unit, data output from the monitoring unit to another device may also be provided, for example, to a control unit of the corresponding compressor, which will be discussed further below.

[0019] Since conventional compressors generate considerable vibrations during their operation, which can sooner or later lead to damage to the ultraviolet irradiation unit, particularly in embodiments in which the filter unit is in direct contact with the compressor, it can be advantageous if the ultraviolet irradiation unit is mounted within the housing in a vibration-damped manner, in particular by means of at least one spring clamp, which is preferably made at least in sections from a ceramic and / or sheet metal material.

[0020] Materials such as ceramic and sheet metal are preferable to cheaper plastic alternatives due to their greater resistance to ultraviolet radiation.

[0021] Alternatively or additionally, particularly in embodiments in which the filter unit according to the invention is to be arranged directly on the housing of the compressor in question, it can comprise at least one holder provided on the outside of the housing, which preferably comprises at least one damping element for mechanical vibrations, for example an elastomer damping element. The holder preferably comprises at least one permanent magnet to enable simple and tool-free attachment to ferrous metal surfaces. Alternatively, however, other attachment means could of course also be provided, for example screws or an adhesive material.

[0022] Although radiation in the entire ultraviolet spectrum has an inactivating effect on viruses, bacteria, etc., the ultraviolet irradiation unit of the filter unit according to the invention can be designed in particular to emit ultraviolet light in the UVC range, preferably at a wavelength of approximately 254 nm. In Lamps emitting in this wavelength range are commercially available and such radiation offers good properties with regard to its absorption in many gases and its reflection from anodised aluminium, as already mentioned, and it also does not lead to the undesirable production of ozone from oxygen, which would occur with even shorter-wave radiation.

[0023] Although the particle pre-filter can be of a wide variety of suitable types, as long as it reliably prevents the penetration of dirt particles into the housing of the filter unit according to the invention, it has been shown that particle pre-filters which are at least of filter class F7 are particularly suitable for this purpose.

[0024] A further contribution to ensuring the intended operation of the filter unit can be provided by providing it with a vacuum monitoring unit designed to notify of an excessive pressure difference between the interior and the surroundings of the housing, and which can be located in particular in the area of ​​the particle pre-filter. This could involve commercially available vacuum monitors that, when such a pressure difference exceeds a predetermined threshold, emit a corresponding signal indicating that the particle pre-filter is clogged with particles accumulated over its service life and needs to be replaced.

[0025] As already mentioned, the present invention relates to a compressor, in particular a breathing air compressor and / or multi-stage piston compressor, comprising a compressor block with at least one compressor motor and a filter unit. Multi-stage piston compressors are known per se to those skilled in the art and, in addition to several piston stages connected in series, usually also comprise cooler, drying, and separator units for treating the compressed gas.

[0026] In the case described above that the filter unit used comprises a monitoring unit and the compressor further comprises a control unit, the control unit can be operatively coupled or integrated with the monitoring unit and can be configured to adapt the operation of the compressor upon detection of a deviation from the correct operation of the ultraviolet irradiation unit, for example to switch off the compressor or to open a flushing valve.In this way, the compressor can prevent insufficiently treated gas from being filled, whereby the use of a purge valve, which allows the compressor to compress the gas sucked in through the filter unit but instead of filling it simply releases it from the compressor into the environment, can prevent repeated switching on and off of at least one compressor motor if there is only a temporary problem with the ultraviolet irradiation unit.

[0027] Alternatively or additionally, the compressor could also comprise a timing unit configured to ensure a time interval between the start-up of the ultraviolet irradiation unit and the at least one compressor motor. This could be a fixed value for such a delay, which experience has shown the irradiation unit used requires to reach its intended power, or an electrical or electronic circuit assigned to the irradiation unit that only releases a start signal for the compressor motor once the intended power has been reached. In this context, the start-up of the at least one compressor motor could also be understood as the closing of a corresponding purge valve.In any case, this measure ensures that filling of the compressed gas only begins once the ultraviolet irradiation unit has reached its intended operating state, for example, once it has completed a warm-up phase.

[0028] Although the filter unit could be flanged directly to a gas inlet of the compressor block with its outlet, an intake hose can also be provided between the filter unit and the compressor block, which is attached to the filter unit outlet, preferably sealed by means of an elastic material. This allows for flexible positioning of the filter unit; for example, the filter unit can be attached to the housing of the compressor block using the permanent magnets mentioned above.

[0029] The compressor according to the invention always comprises a safety device designed to ensure that operation of the compressor is only possible when the filter unit is in operation, for example, based on the above-described monitoring unit of the filter unit. The safety device additionally comprises means by which operation of the compressor can be permitted, exceptionally, even in cases where the filter unit is not in operation, for example, when, in the event of a disaster, the availability of the basic function of the compressor outweighs the disadvantages of the filter unit being out of operation. Such means can include, among others, a key switch or a code input device.

[0030] Finally, the present invention relates to a method for compressing and filling breathing air by means of a compressor according to the invention, wherein the breathing air to be compressed is sucked through the filter unit, then compressed by the at least one compressor motor and finally filled at a pressure of, for example, between 90 and 550 bar.

[0031] Further features and advantages of the present invention will become even clearer from the following description of an embodiment when considered together with the accompanying figures. These show in detail: Figure 1 shows a filter unit in schematic side view; Figure 2 shows the filter unit from Figure 1 in a sectional view along a section plane AA Figure 1 ; and Figures 3a and 3b show enlarged detail views of two areas from Figure 2 .

[0032] In the Figures 1 and 2Each of the figures shows a filter unit of a compressor according to the invention, which is generally designated by the reference numeral 10. The filter unit 10 comprises a multi-part housing 12, which has a gas inlet 14 on a first part 12a, the uppermost part in the figures, to which an intake hose can optionally be connected. The individual parts of the multi-part housing 12 described below are each firmly connected to one another, for example, riveted, screwed, welded, or the like, whereby in some embodiments, several of the parts of the housing 12 can also be formed integrally with one another.

[0033] In this first part 12a of the housing 12, a filter material is accommodated in a chamber, forming an annular particle pre-filter 16 through which the gas flowing in through the inlet 14 passes before entering the actual interior of the housing 12. Also assigned to the first part 12a of the housing 12, the filter unit 10 comprises a negative pressure monitoring unit 18 for indicating a possible blockage of the particle pre-filter 16. By closing the first part 12a of the housing 12 at its top by a releasably clamped and sealed cap 12e, an openable access to the interior of the housing 12 can be created at this point, through which the filter material of the particle pre-filter 16 can be removed and replaced at regular intervals, for example.

[0034] Below the first part 12a there is a second part 12b of the housing 12, which Figure 3ais shown again in an enlarged detailed view and in which a first attachment element 20a for a rod-shaped ultraviolet irradiation unit 22 is arranged, which can be inserted and replaced by unscrewing and removing the second part 12b, which is screwed onto the third part 12c of the housing 12 (described below) by means of a thread not shown. The irradiation unit 22 can, for example, be designed as a fluorescent tube for ultraviolet light at a wavelength of approximately 254 nm, by means of which any viruses, bacteria, spores, etc. present in the gas flowing within the housing can be inactivated or killed.

[0035] In the embodiment shown, the first attachment element 20a is formed by a spring clamp that holds the irradiation unit 22 in a vibration-damped manner, with a socket 24 for supplying the irradiation unit 22 with electricity being removably attached thereto from above. Furthermore, on the outside of the second part 12b of the housing 12, there is a cable gland 26 to which a power cable for supplying the ultraviolet irradiation unit can be attached. Furthermore, an electrical connection (not visible in the figures) between the cable gland 26 and the socket 24 is provided within the second part 12b of the housing 12.

[0036] From the first attachment element 20a, the irradiation unit 22 extends through a third part 12c of the housing 12 to a fourth part 12d, in which it is held in an analogous manner by a second attachment element 20b, which in Figure 3bis also shown in an enlarged detail view. Here, the third part 12c of the housing 12 is made of anodized aluminum, since this material reflects ultraviolet light of the aforementioned wavelength and thus both increases the efficiency of the device and counteracts excessive heating. The other parts of the housing 12 can also be made of aluminum or of another material, such as stainless steel, since they are significantly less exposed to the radiation from the irradiation unit 22.

[0037] Finally, on the underside of the fourth part 12d of the housing 12, a flange-shaped outlet 28 is attached, to which, in the configuration shown in the figures, an intake hose 30 is attached, through which the irradiated gas can be fed to a compressor block (not shown here). It should be noted that in the area of ​​the third and fourth parts 12c, 12d of the housing 12 and the outlet 28, no further accesses to the interior of the housing 12 are provided, so that on this side of the filter unit 10, where the gas has already been irradiated and is thus in a state ready for compression and ultimately filling, no complex measures need to be taken to seal the housing 12, and at the same time, critical contamination of the treated gas is reliably excluded.

[0038] Furthermore, it should be noted that on the outside of the housing 12, in particular in the area of ​​the third part 12c thereof, two brackets 34 are mounted by means of mounting clamps 32. Each bracket comprises an elastomer damping element 36 and a permanent magnet 38, and by means of which the filter device 10 can be attached to a surface made of a ferrous metal, for example, an outer side of the compressor system (not shown). Together with the above-mentioned attachment elements 20a and 20b, the damping elements 36 serve to decouple the filter device 10, and in particular the ultraviolet irradiation unit 22, from the vibrations and shocks occurring during operation of the compressor block.

[0039] Furthermore, a ballast 40 in the form of a switch box is similarly mounted on the housing 12 by means of two mounting clamps 32. This ballast performs all control functions necessary for the operation of the filter unit 10, and in particular the ultraviolet irradiation unit, as well as providing the electrical supply via a further cable gland 42 and a cable (not shown). The ballast 40 itself is powered from the mains via a connection (not shown), so that the filter unit 10 can be operated independently of this.The ballast 40 may further be operatively coupled to other electronic components that are optionally provided and not shown here, such as sensors for the ambient temperature or the temperature of the gas sucked into the filter unit 10, a monitoring unit for the function of the ultraviolet irradiation unit, a notification unit for a user and / or a control unit of the compressor block.

Claims

1. Compressor, in particular a breathing air compressor and / or multi-stage piston compressor, comprising a compressor block with at least one compressor motor and a filter unit (10), the filter unit (10) comprising: - a housing (12) having an inlet (14) and an outlet (28) for gas to be compressed; - a particle pre-filter (16) arranged downstream of the inlet (14) in the flow direction of the gas to be compressed; - an ultraviolet irradiation unit (22) which is arranged downstream of the particle pre-filter (16) in the flow direction of the gas to be compressed and is configured to emit ultraviolet light; and - a ballast (40) which is configured and arranged to control the ultraviolet irradiation unit (22); wherein the filter unit (10) is designed in such a way that gas to be compressed which is fed in at the inlet (14) first passes through the particle pre-filter (16), is then irradiated by the ultraviolet irradiation unit (22) and can finally be fed to the compressor through the outlet (28), characterized in that the compressor further comprises a safety device which is configured to ensure that operation of the compressor is only possible when the filter unit is in operation, and which additionally comprises means by which operation of the compressor can exceptionally also be allowed in cases in which the filter unit is not in operation.

2. Compressor according to claim 1, in which the housing (12) in the area of the ultraviolet irradiation unit (22) is made at least partially, preferably completely, of anodised aluminium, in particular on the inside, wherein, for example, cartridge tubes, in particular with article numbers 61089, 62333 and 60174, can be used.

3. Compressor according to any of the preceding claims, wherein the housing (12) is elongate, in particular cylindrical, for example circular-cylindrical, in the region of the ultraviolet irradiation unit (22).

4. Compressor according to any of the preceding claims, wherein the ballast (40) is further configured to adapt the control of the ultraviolet irradiation unit (22) to an ambient temperature and / or a temperature of the gas to be compressed, which can be entered by a user using an input unit or can be detected by a sensor unit.

5. Compressor according to any of the preceding claims, further comprising a monitoring unit which is configured to monitor correct operation of the ultraviolet irradiation unit (22).

6. Compressor according to claim 5, further comprising a notification unit which is operatively coupled to the monitoring unit and is configured to output a notification when a deviation from the correct operation of the ultraviolet irradiation unit (22) is detected.

7. Compressor according to any of the preceding claims, wherein the ultraviolet irradiation unit (22) is fastened inside the housing (12) in a vibration-damped manner, in particular by means of at least one spring clip (20a, 20b), which is preferably made at least partially from a ceramic and / or sheet metal material.

8. Compressor according to any of the preceding claims, further comprising at least one bracket (34) which is provided on the outside of the housing (12) and preferably comprises at least one damping element (36) for mechanical vibrations, for example an elastomeric damping element, wherein the bracket (34) preferably comprises at least one permanent magnet (38).

9. Compressor according to any of the preceding claims, wherein the ultraviolet irradiation unit (22) is configured to emit ultraviolet light in the UVC range, preferably at a wavelength of about 254 nm.

10. Compressor according to any of the preceding claims, wherein the particle pre-filter (16) is at least of filter class F7.

11. Compressor according to any of the preceding claims, further comprising a vacuum monitoring unit (18) which is configured to provide a notification of an excessive pressure difference between the interior and the surroundings of the housing (12), and which can be arranged, in particular, in the region of the particle pre-filter (16).

12. Compressor according to any of claims 5 to 11, further comprising a control unit which is operatively coupled to or integrated with the monitoring unit and is configured to adapt the operation of the compressor, for example to switch off the compressor or to open a flush valve, when a deviation from the correct operation of the ultraviolet irradiation unit (22) is detected.

13. Compressor according to any of the preceding claims, further comprising a timing unit which is configured to ensure a time interval between a start-up of the ultraviolet irradiation unit (22) and of the at least one compressor motor.

14. Compressor according to any of claims 12 to 14, wherein a suction hose (30) which is attached, preferably sealed by means of elastic material, to the outlet (28) of the filter unit (10) is provided between the filter unit (10) and the compressor block.

15. Compressor according to any of the preceding claims, wherein the safety device comprises means by which operation of the compressor can exceptionally also be allowed in cases in which the filter unit is not in operation.

16. Method for compressing breathing air using a compressor according to any of the preceding claims, wherein the breathing air to be compressed is drawn in through the filter unit (10), then compressed by the at least one compressor motor and finally bottled at a pressure of, for example, between 90 and 550 bars.