Insulator with ventilation arrangement, and method for ventilating the working region of an insulator

Abstract

In an insulator having a working region and having a ventilation arrangement which has a pressure monitoring circuit which, during use, automatically detects the internal pressure (pi) prevailing in the working region and compares it with a reference pressure detected outside the working region for the purpose of determining a quantitative differential pressure between the internal pressure (pi) and the external reference pressure, and, in the event of a quantitative differential pressure of less than or equal to Pa, automatically raises the internal pressure (pi), the invention proposes that the ventilation arrangement has a compressed air accumulator which is connected to the working region and in which an accumulator pressure prevails which is at least as high as the setpoint pressure of the working region, wherein an air line runs from the compressed air accumulator to the working region, which air line can be selectively interrupted or flowed through by means of a shut-off valve, and that the pressure monitoring circuit is designed in such a way that the shut-off valve is automatically opened at a quantitative differential pressure of less than or equal to 50 Pa.

Description

[0001] "Isolator with ventilation arrangement, and method for ventilating the working area of ​​an isolator"

[0002] Description:

[0003] The invention relates to an isolator according to the preamble of claim 1 and a method for ventilating the working area of ​​such an isolator.

[0004] Such isolators are used in the pharmaceutical sector. Depending on their design, some isolators are also referred to in practice as "large-capacity isolators": a "large-capacity isolator," for example, is large enough to accommodate people, e.g., for maintenance purposes and to install equipment used for fully automated handling of the pharmaceutical product (feeding, filling, and removing it from the isolator). Smaller isolators are used, for example, for small batches and for testing purposes, e.g., during the trial phase of the pharmaceutical product. They are not fully automated and have, for example, reach-through openings for gloves, so that the aforementioned handling of the pharmaceutical product can be carried out manually, with the personnel outside the isolator.

[0005] A generic isolator used for work in the pharmaceutical industry, as well as a method for ventilating its work area, are known from practice. In a work area of ​​the isolator, also referred to as a production room, there is an internal pressure that is regulated by the supply and exhaust air volume flows of the so-called working air, namely the air used to ventilate the work area. The supply and exhaust air volume flows are regulated in a technical area of ​​the isolator by the supply air in a suction plenum and the exhaust air extraction in a pressure plenum. The supply and exhaust air units used in this isolator, which is known from practice, are designed as independent filter systems with their own drives.They ensure the air exchange rate in the work area, through which the working air flows from top to bottom, and return the air volume lost through the isolator openings to the work area. The internal pressure in the work area is measured below the air outlet surface and differentiated from the neighboring sections and surrounding rooms. The air pressure measured outside the work area is called the reference pressure and forms the starting point for the ventilation of an isolator. The difference between the internal pressure and the external reference pressure is called the differential pressure. A differential pressure of 10-15 Pa (guideline value) is generally targeted.

[0006] The internal pressure is controlled by controlling the exhaust air unit, e.g., the exhaust fan and an exhaust air damper, and thus by adjusting the volume of air to be discharged. For this purpose, the isolator has a ventilation arrangement that includes, among other things, a pressure monitoring circuit, by means of which the internal pressure in the working area is automatically and practically continuously recorded and compared with a reference pressure. The resulting differential pressure can form the basis for determining various internal pressure control parameters:

[0007] • For example, the measured internal pressure can be compared with a target pressure. • For example, the measured internal pressure can be compared with a lower limit of a pressure that must not be exceeded and can be referred to as the limit pressure.

[0008] • For example, the recorded internal pressure can be compared with an alarm value of a pressure below which an alarm is triggered and can be referred to as alarm pressure.

[0009] The control parameters setpoint pressure, limit pressure and / or alarm pressure can thus represent different differential pressures.

[0010] In one embodiment, for example, if the setpoint pressure is undershot by a certain amount, namely when a so-called alarm pressure is reached when approaching the limit pressure, the pressure monitoring circuit can cause the internal pressure to be automatically raised to at least the setpoint value, so that a pressure drop to the limit pressure is avoided.

[0011] An unacceptably large deviation when comparing the internal pressure with the target pressure can, for example, mean that the two pressure values ​​differ significantly. When comparing the internal pressure with the limit pressure, however, the two pressure values ​​should differ significantly, so in this case, an unacceptable deviation occurs when the deviation between the two pressure values, the internal pressure and the limit pressure, is too small.

[0012] In general, an impermissibly large deviation in the context of the invention may consist in the fact that a differential pressure between the (actual) internal pressure and the reference pressure, in particular when maintaining the differential pressure over a period of time, for example of more than 5 s, is associated with the risk that the isolator loses its production release and / or the isolator loses its aseptic status, as a result of which it is no longer considered suitable for production, which may be accompanied by considerable economic disadvantages.

[0013] Severe pressure fluctuations are prevented during normal operation by the employees' standard operating procedures (SOPs). For example, slow movements by employees are required, including the use of gloves during the process and when inserting or removing isolator openings to a surrounding room or neighboring sections. However, it cannot be ruled out that severe pressure fluctuations may occur due to human error or excessively rapid movements, resulting in an internal pressure in the work area that deviates from the specified target value. In some cases, the pressure may even fall below the limit pressure, meaning that the basic requirements for a GMP-compliant process cannot be met and the isolator loses its production approval.

[0014] If this condition of pressure below the limit persists for more than 5 seconds, the isolator loses its aseptic status and is considered no longer suitable for production. This is economically disadvantageous: in addition to the costs of production downtime and the lost material, there are the costs of extensive cleaning to restore the aseptic status and resume production.

[0015] The invention is based on the object of improving a generic isolator such that it ensures the maintenance of a predetermined internal pressure in the working area as reliably as possible, in particular enabling the restoration of the predetermined internal pressure as quickly as possible in the event of a pressure drop. Furthermore, the invention is based on the object of specifying a method for ventilating the working area with the aforementioned advantages. This object is achieved by an isolator having the features of claim 1 and by a method according to claim 7. Further advantageous aspects, details, and embodiments of the invention emerge from the dependent claims and the description.

[0016] According to a first aspect, an insulator is proposed,

[0017] • with a working area in which a predetermined internal pressure (pi) corresponding to a target pressure prevails,

[0018] • a supply air area from which working air flows into the working area during use,

[0019] • an exhaust air area into which the working air flows from the work area during use, and with a ventilation arrangement that has the following elements:

[0020] • Filter units that are located in the supply air area and / or in the exhaust air area and are passed through by the working air during use,

[0021] • at least one blower unit which, when in use, sets the working air in flow,

[0022] • and a pressure monitoring circuit which is designed in such a way that the internal pressure (pi) prevailing in the working area is automatically recorded and compared with a reference pressure recorded outside the working area to determine a differential pressure between the internal pressure (pi) and the external reference pressure o and, if the differential pressure is less than or equal to 10 Pa, preferably less than or equal to 15 Pa, the internal pressure (pi) is automatically raised, in particular raised to at least the target pressure, wherein the ventilation arrangement has a compressed air reservoir in which a storage pressure prevails which is at least as high as the target pressure of the working area, wherein the compressed air reservoir is connected to the working area in such a way that an air line runs from the compressed air reservoir to the working area, wherein the air line can be selectively interrupted or flowed through by means of a shut-off valve,and wherein the pressure monitoring circuit is designed in such a way that the shut-off valve is automatically opened when the differential pressure is less than or equal to 50 Pa.,

[0023] In other words, the invention proposes that, in the event of a pressure drop, pressure equalization be achieved by introducing a sufficiently pressurized amount of air into the work area. The invention is based on the consideration that, although influencing the working air blower units is fundamentally suitable for setting the desired internal pressure in the work area, the response behavior of a blower unit is too sluggish to achieve the desired pressure equalization within the shortest possible time. Instead, the ventilation arrangement according to the invention has a compressed air reservoir so that a specific volume of air is constantly available. The pressure level within the compressed air reservoir is at least as high as the target pressure of the work area.If the internal pressure in the working area drops unacceptably far below the target pressure, namely to an alarm pressure, air can flow from the compressed air reservoir into the working area, preventing a further pressure drop down to, for example, a limit pressure. For this purpose, the compressed air reservoir is connected to the working area via an air line. According to the invention, this air line can be selectively opened or closed using a shut-off valve.

[0024] During normal operation, the air line is blocked, i.e., interrupted, by the shut-off valve. However, if the internal pressure in the working area drops to a differential pressure, for example, to the aforementioned alarm pressure, the shut-off valve is automatically opened by the pressure monitoring circuit, allowing the stored compressed air to flow through the air line from the compressed air reservoir into the working area with virtually no delay, increasing the internal pressure prevailing there. The switching process to open the shut-off valve can take place in a considerably shorter time than an equally effective change in the fan speed, so that the inventive design of the ventilation arrangement can achieve a considerably faster change in the pressure conditions.It can therefore be assumed that an inadmissibly long undershoot of a limit pressure, for example, by such a degree that this would lead to a loss of aseptic status, can be prevented with high reliability in practice for almost all common pressure fluctuations. The short reaction time enabled by the invention can even prevent a pressure drop, for example, down to a limit pressure, so that this pressure is not only not undershot for a certain period of time, but is never reached in the first place.

[0025] The pressure monitoring circuit can be designed in the form of an electronic control system to which one or more sensors and actuators can be connected, for example pressure sensors and actuators for opening or closing valves. The internal pressure in the working area is monitored practically continuously, e.g. detected by sensors and compared with the target pressure, namely several times per second, e.g. at intervals of 3 to 5 ms. As an alternative to an electronic control system, the pressure monitoring circuit can also be managed by a number of separate elements which do not have to be interconnected by a common control system, but which rather each act independently, e.g. in the form of valves which switch automatically depending on the pressure, for example changing their switching position when a certain pressure level is exceeded or undershot, e.g. opening to different widths or automatically opening or closing completely.Close completely automatically. In a further development, it can be provided that a pressure monitoring circuit is assigned to the compressed air reservoir, which is designed such that the reservoir pressure prevailing in the compressed air reservoir is automatically monitored and, in the event of a pressure drop, the pressure within the compressed air reservoir is automatically increased to a predetermined target reservoir pressure.

[0026] The target accumulator pressure is preferably at least as high as the target pressure of the working area. For this purpose, it can further be provided that the pressure monitoring circuit preferably automatically increases the accumulator pressure if, for example, an increased reference pressure is detected and the internal pressure thus needs to be increased in order to be able to map the intended target pressure as the desired differential pressure between the internal pressure and the external reference pressure.

[0027] Furthermore, it can be provided that the pressure monitoring circuit assigned to the compressed air reservoir has a pressure control valve.

[0028] In one embodiment, a pressure monitoring circuit is also assigned to the compressed air reservoir. This can be the pressure monitoring circuit of the isolator or a separate pressure monitoring circuit assigned exclusively to the compressed air reservoir. The so-called reservoir pressure prevailing in the compressed air reservoir is automatically monitored by this pressure monitoring circuit, and if the reservoir pressure drops, the pressure within the compressed air reservoir is automatically increased to a predetermined target reservoir pressure. This can be achieved, for example, by means of a pressure control valve, which allows compressed air to flow from a compressor or from another, higher-level compressed air reservoir into the compressed air reservoir of the isolator's ventilation system as needed.The pressure monitoring circuit of the compressed air reservoir works by filling the compressed air reservoir with compressed air upon initial startup until a predetermined reservoir pressure is reached inside the compressed air reservoir. The compressed air reservoir is then automatically refilled with compressed air at regular intervals when the pressure level drops below a predetermined reservoir pressure limit and / or, as previously described, the reference pressure increases. This can occur due to losses in the form of leaks, or because the compressed air reservoir has released compressed air into the isolator's working area.

[0029] According to one embodiment, it can be provided that the shut-off valve arranged in the air line is designed as a solenoid valve.

[0030] In one embodiment, a solenoid valve is used as a shut-off valve, which selectively opens or closes the air line between the compressed air reservoir and the work area. This enables rapid response and thus short reaction times of the ventilation system to a pressure drop in the work area, since the solenoid valve changes its switching state in the single-digit millisecond range. Furthermore, the use of a solenoid valve allows the shut-off valve to be controlled by an electronic control of the pressure monitoring circuit.

[0031] Furthermore, it can be provided that several compressed air storage units are connected to the work area.

[0032] The volume of working air contained in the work area depends on the size of the work area. To compensate for a pressure drop as quickly as possible, a correspondingly large air volume must be provided in the compressed air reservoir. An economically advantageous option for adapting the ventilation arrangement to the different sized work areas of different isolators is to provide the total volume of stored compressed air not in one, but, if necessary, in two or more compressed air reservoirs. In this way, the ventilation arrangement can be easily scaled without the need to provide compressed air reservoirs of different sizes, each with its own required type approval.

[0033] In order to keep the reaction time as short as possible in the event of a pressure drop in the work area, two or more compressed air storage units can be used so that a correspondingly large amount of stored compressed air can be fed into the work area at a comparatively high pressure level.

[0034] Finally, even in cases where a single compressed air reservoir is sufficient to equalize the internal pressure prevailing in the work area, the isolator's ventilation arrangement can incorporate two or more compressed air reservoirs. This allows the stored compressed air to maintain the desired internal pressure level in the work area even in the rare cases where the internal pressure drops in quick succession. This way, the second compressed air reservoir provides sufficient time to ensure safe operation of the isolator until the first, empty compressed air reservoir is refilled and ready for use.

[0035] In a further development, it can be provided that the compressed air storage units are each connected to the work area by means of their own air line.

[0036] If more than one compressed air reservoir is used, these can be connected to a common air line. In one embodiment, however, the compressed air reservoirs are each connected to the work area via their own air line. This also shortens the response time for compensating a pressure drop in the work area, because it supports the flow of the largest possible amount of compressed air at the highest possible pressure level into the work area.

[0037] Alternatively or in addition to the previous explanation, an insulator can be provided in the sense of the invention,

[0038] • with a working area in which a predetermined internal pressure pi corresponding to a target pressure prevails,

[0039] • a supply air area from which working air flows into the working area during use,

[0040] • an exhaust air area into which the working air flows from the work area during use, and with a ventilation arrangement that has the following elements:

[0041] • Filter units that are located in the supply air area and / or in the exhaust air area and are passed through by the working air during use,

[0042] • at least one blower unit which, when in use, sets the working air in flow,

[0043] • and a pressure monitoring circuit which is designed in such a way that o the internal pressure pi prevailing in the working area is automatically recorded and compared with a reference pressure o and in the event of an inadmissibly large deviation from the reference pressure, the internal pressure pi is automatically raised to at least the target pressure, wherein the ventilation arrangement has a compressed air reservoir in which a storage pressure prevails which is at least as high as the target pressure of the working area, wherein the compressed air reservoir is connected to the working area in such a way that an air line runs from the compressed air reservoir to the working area, wherein the air line can be optionally interrupted or flowed through by means of a shut-off valve, and wherein the pressure monitoring circuit is designed in such a way that in the event of an inadmissibly large deviation from the reference pressure, the shut-off valve is automatically opened.

[0044] According to a further aspect, a method for ventilating the working area of ​​an isolator is proposed, wherein working air is supplied from the outside to the working area and is led out of the working area to the outside, and wherein an air pressure referred to as internal pressure pi is built up within the working area, which air pressure corresponds to a specific target pressure, and wherein the internal pressure pi is automatically maintained above a specific limit pressure p by means of a pressure monitoring circuit. g maintained by increasing the amount of air supplied to the working area when the internal pressure pi reaches a certain alarm pressure p a which is below the internal pressure pi and above the limit pressure p gwherein compressed air is provided in a compressed air reservoir, said compressed air being at a storage pressure prevailing in the compressed air reservoir which is at least as high as the target pressure of the working area, and wherein, in order to increase the amount of air supplied to the working area, a shut-off valve is opened in such a way that air now flows from the compressed air reservoir through an air line into the working area.

[0045] In particular, it can be provided that the insulator with a number of the features described above is used to carry out the method according to the invention.

[0046] In a further development of the method, it can be provided that one or more pressures according to the following list of pressures are formed as a differential pressure between the internal pressure pi and a reference pressure recorded outside the working range: Limit pressure p g , alarm pressure p a, target pressure. The invention is explained in more detail below using the example of the operation of a ventilation arrangement of an insulator according to the invention.

[0047] Fig. 1 shows the temporal course of the internal pressure in the working area of ​​an isolator with pressure conditions shown purely as examples.

[0048] Fig. 1 shows a diagram in which the pressure p is plotted against time t. An upper line with different pressure values ​​represents an internal pressure pi prevailing in the working area of ​​an isolator. Below this, a horizontal line with a constant pressure value indicates a defined limit pressure p g, which must not be undercut within the work area under normal circumstances. In the example shown, the overpressure in Pa prevailing in the work area compared to the rooms adjacent to the work area (reference pressure) is plotted on the vertical axis. Accordingly, in the example shown, the internal pressure pi in the work area should not fall below a limit of 15 Pa, and the target internal pressure during normal operation is approximately 26 to 30 Pa.

[0049] Sudden pressure fluctuations occurring in the working area can in practice be so large that the limit pressure p g In such exceptional cases, it must be ensured that the limit pressure p g does not exceed a specified period of time and ideally a pressure drop down to the limit pressure p gcan even be completely avoided. The internal pressure pi prevailing in the working area is monitored almost continuously by a pressure monitoring circuit, for example by pressure measurements at intervals of 3 ms. If the pressure falls below an alarm pressure p a which is higher than the limit pressure p g , an error signal is automatically generated. In the example shown, a compressed air reservoir is assigned to the working area. Using the pressure monitoring circuit, the actual internal pressure pi is compared with a desired differential pressure, for example, with a specific target pressure or with the alarm pressure p a , which in the example shown is 20 Pa. The first pressure drop shown in Fig. 1, occurring at time ti, is so short-term that its deviation from the target pressure is so slight that the internal pressure pi does not reach the alarm pressure p aHowever, the pressure drop that occurs shortly thereafter at time te deviates so much from the target pressure that the internal pressure pi drops below the alarm pressure p a sinks.

[0050] The pressure monitoring circuit is used to trigger an alarm if the alarm pressure p is exceeded. a A solenoid valve is automatically activated, which opens an air line leading from the aforementioned compressed air reservoir to the work area. Within a very short reaction time of, for example, approximately 8 ms, the air line is opened, and compressed air can flow from the compressed air reservoir into the work area. Accordingly, as shown in Fig. 1, the internal pressure Pi drops after reaching the alarm pressure p a only decreases slightly further and does not drop to the value of the limit pressure p gRather, there is a rapid pressure increase up to a maximum value of 38 Pa at time ts, when the compressed air reservoir is almost completely empty. From time ts onward, the internal pressure pi then drops back to the target value, as the internal pressure is regulated back to the target value range by the ventilation arrangement.

[0051] The air line is then automatically closed again by the solenoid valve, so that the compressed air reservoir can then be automatically refilled via a pressure control valve and is ready for the next use. The invention is not limited to one of the previously described embodiments, but can be modified in many ways. All information arising from the claims, the description and the

[0052] The features and advantages apparent from the drawing, including structural details, spatial arrangements and process steps, may be essential to the invention both individually and in a wide variety of combinations.

[0053] Reference symbol:

[0054] Pi internal pressure p a Alarm pressure p g Limit pressure ti Time of first pressure drop t2 Time of second pressure drop ts Time of pressure maximum

Claims

Claims: 1 . Insulator, • with a working area in which a predetermined internal pressure (pi) corresponding to a target pressure prevails, • a supply air area from which working air flows into the working area during use, • an exhaust air area into which the working air flows from the work area during use, and with a ventilation arrangement that has the following elements: • Filter units that are located in the supply air area and / or in the exhaust air area and are passed through by the working air during use, • at least one blower unit which, when in use, sets the working air in flow, • and a pressure monitoring circuit which is designed in such a way that the internal pressure (pi) prevailing in the working area is automatically recorded and compared with a reference pressure recorded outside the working area to determine a differential pressure between the internal pressure (pi) and the external reference pressure o and in the case of a differential pressure of less than or equal to 10 Pa, preferably less than or equal to 15 Pa, the internal pressure (pi) is automatically raised, in particular raised to at least the target pressure, characterized in that the ventilation arrangement has a compressed air reservoir in which a storage pressure prevails which is at least as high as the target pressure of the working area, wherein the compressed air reservoir is connected to the working area in such a way that an air line from Compressed air reservoir runs to the working area, wherein the air line can be selectively interrupted or flowed through by means of a shut-off valve, and that the pressure monitoring circuit is designed in such a way that the shut-off valve is automatically opened when the differential pressure is less than or equal to 50 Pa.

2. Isolator according to claim 1, characterized in that the compressed air reservoir is assigned a pressure monitoring circuit which is designed in such a way that the storage pressure prevailing in the compressed air reservoir is automatically monitored and, in the event of a pressure drop, the pressure within the compressed air reservoir is automatically increased to a predetermined target storage pressure.

3. Isolator according to claim 1 or 2, characterized in that the pressure monitoring circuit associated with the compressed air reservoir comprises a pressure control valve.

4. Isolator according to one of the preceding claims, characterized in that the shut-off valve arranged in the air line is designed as a solenoid valve.

5. Isolator according to one of the preceding claims, characterized in that several compressed air reservoirs are connected to the working area.

6. Isolator according to claim 5, characterized in that the compressed air reservoirs are each connected to the working area by means of a separate air line.

7. Method for ventilating the working area of an isolator, wherein working air is supplied from outside to the working area and led out of the working area to the outside, and wherein an air pressure referred to as internal pressure (pi) is built up within the working area, which air pressure corresponds to a certain target pressure, and wherein the internal pressure (pi) is automatically maintained above a certain limit pressure (p g) by increasing the amount of air supplied to the working area when the internal pressure (pi) reaches a certain alarm pressure (p a ) which is below the internal pressure (pi) and above the limit pressure (p g ), characterized in that compressed air is provided in a compressed air reservoir, which is under a storage pressure prevailing in the compressed air reservoir which is at least as high as the target pressure of the working area, and that in order to increase the amount of air supplied to the working area, a shut-off valve is opened in such a way that air now flows from the compressed air reservoir through an air line into the working area.

8. Method according to claim 7, characterized in that one or more pressures according to the following list of pressures are formed as a differential pressure between the internal pressure (pi) and a reference pressure detected outside the working range: limit pressure (p g ), alarm pressure (pa ), target pressure.

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