FR3111282A1 - Clean room with particle level monitoring - Google Patents

Abstract

The invention relates to a clean room having at least one volume delimited by partitions associated with each other and fixed to the ground and, optionally, to at least one wall of a building, comprising at least one entrance door, at least one unit filtration and ventilation unit (FFU), at least one opening associated with a filter, and advantageously a system for instantaneously determining the level of particles within the latter, which system comprises at least one particle counter, at least one user interface capable of displaying the instantaneous level of particles within the clean room; and at least one central processing unit connected to the particle counter and able to process the information detected by this sensor to enable its display on the user interface.

Description

Clean room with particle level monitoring

The present invention relates to a new device of the clean room type.

Prior art

A clean room or clean room is a room in which the concentration of airborne particles is controlled and which is constructed and used in such a way as to minimize the introduction, production and retention of particles inside the room, and in which other relevant parameters, such as temperature, humidity and pressure are controlled as appropriate.

In other words, a clean room is a room where the contamination of the air by suspended particles is controlled in granulometry and in number per cubic meter of air. This contamination can be of several types: particulate, microbiological and/or chemical. The ISO 14644 standards define clean room classes according to this number of particles for a given particle size.

Such a clean room can be used in particular in the hospital field to protect patients.

For use in a hospital environment, it is essential to ensure the monitoring and to guarantee the conformity of the critical parameters inside the clean room, such as the concentration of particles in the air or the pressure.

It is therefore necessary to develop solutions integrated into clean rooms allowing the monitoring of critical parameters attesting to their proper functioning.

The inventors have developed a clean room integrating solutions for monitoring the concentration of particles in the air thereof, making it possible to simplify their use in a hospital environment and improve safety for the patient.

Consequently, the present invention relates to a clean room having at least one volume delimited by partitions associated with each other and fixed to the ground and, optionally, to at least one wall of a building, comprising:
• At least one entrance door;
• At least one filtration and ventilation unit (FFU);
• At least one opening associated with a filter;
characterized in that it further comprises a system for instantaneously determining the level of particles within it, which system comprises:
1) At least one particle counter,
2) At least one user interface capable of displaying the instantaneous level of particles within the clean room; And
3) At least one central processing unit connected to the particle counter and able to process the information detected by this sensor to enable its display on the user interface.

Advantageously, the user interface of the clean room according to the invention displays the instantaneous level of particles within the clean room according to the ISO 14644-1 classification.

Still advantageously, the particle counter of a clean room according to the invention is able to measure the concentration of particles having a size greater than or equal to 5 μm.

According to a particular embodiment, the clean room according to the invention further comprises at least one pressure sensor located inside said clean room, and at least one pressure sensor located outside said clean room, said sensors being connected to the central processing unit.

Advantageously, the user interface of a clean room according to the invention also displays at least the measured pressure difference dP between the inside and the outside of the clean room, the temperature of the clean room, the operating flow rate of the air treatment and filtration unit and at least one signal related to the compliance of the measured pressure difference dP between the inside and the outside of the clean room with a set value.

Said at least one signal related to the conformity of the measured pressure difference dP between the inside and the outside of the clean room with a set value can be a first signal S0 if the measured pressure difference dP is equal to the set value or differs from it by up to 2 Pa, a second signal S1 if the measured pressure difference dP differs from the set value by more than 2 Pa up to 5 Pa, a third signal S2 if the measured pressure difference dP differs from the set value by more than 5 Pa.

Advantageously, the central processing unit of a clean room according to the invention is also connected to a memory, for example RAM bars, capable of recording the variations of the various parameters measured over time.

Still advantageously, the clean room according to the invention is able to operate under depression, that is to say that the pressure inside the clean room is lower than atmospheric pressure.

Alternatively, the clean room according to the invention is capable of operating under overpressure, that is to say that the pressure inside the clean room is greater than atmospheric pressure.

According to a particular embodiment, the user interface of the clean room according to the invention emits a signal linked to the compliance of the level of particles in the clean room with respect to a set level. Advantageously, said signal related to the conformity of the level of particles emitted by the user interface of a clean room according to the invention is a visual and/or sound signal.

Detailed description of the invention

The subject of the present invention is a clean room having at least one volume delimited by partitions associated with each other and fixed to the ground and, optionally, to at least one wall of a building, comprising:
• At least one entrance door;
• At least one filtration and ventilation unit (FFU);
• At least one opening associated with a filter;
characterized in that it further comprises a system for instantaneously determining the level of particles within it, which system comprises:
1) At least one particle counter,
2) At least one user interface capable of displaying the instantaneous level of particles within the clean room; And
3) At least one central processing unit connected to the particle counter and able to process the information detected by this sensor to enable its display on the user interface.

The construction materials of such a clean room are known from the prior art. Advantageously, the partitions take the form of panels which are made of a material capable of being washed, sterilized and/or decontaminated. By way of example, such partitions are made of plastic, composite, metal or a mixture of those; which partitions are preferably covered with a layer of paint or suitable varnish.

In order to meet the needs of a clean room, the partitions are airtight. To guarantee this tightness, seals are placed between the different partitions as well as between the partitions and the floor.

According to a particular embodiment, the clean room can comprise a frame on which the partitions are fixed. Such a reinforcement is useful in particular in the case where the partitions do not have sufficient rigidity to permanently delimit the clean room once assembled.

Such a framework can be produced using techniques well known to those skilled in the art. Typically, it may consist of tubes, rods or even plastic, composite or even metal rails assembled together to form a structure.

Advantageously, the frame is metallic.

The assembly of this frame is also done according to techniques well known to those skilled in the art. Typically, this assembly can be made using screws, rivets or even glue.

Now, and according to another particular embodiment, the partitions of the clean room have sufficient rigidity to be assembled together without requiring the use of additional reinforcement.

Typically, such a partition then has a thickness of between 40 and 150 mm.

Preferably, the partitions used are sandwich panels. Such sandwich panels have an outer wall and an inner wall between which there is a space. Preferably, this intermediate space incorporates an insulating material such as polyurethane foam, expanded or extruded polystyrene, mineral wool (rock or glass).

In any case, the structure of the clean room has flexibility allowing easy assembly so as to be quickly mobilized and deployed for occasional and/or temporary conditions, in emergency or makeshift situations.

In its simplest configuration, the clean room according to the invention has a parallelepiped shape.

Now, the constructive system makes it possible to give it much more complex shapes according to the needs.

As regards the entrance door, it is advantageously sliding, preferably this sliding door is motorized and its opening is controlled by an opening control located on the facade of the clean room near the door and at a height allowing it to be operated by an operator.

Typically, such an opening system can be operated by pressure from the operator's hand or elbow. Such an opening system can also be controlled by reading a specific badge or a specific signature (fingerprint, etc.).

The entrance door can preferably be made of transparent material, preferably glass (eg safety glass).

The entrance door helps to maintain the tightness of the clean room from the outside.

Now, and insofar as the clean room is likely to be in overpressure or in depression, exchanges of air must nevertheless take place between the clean room and the external space.

In this context, an opening associated with a filter allows the decompression of the air when the clean room is in overpressure or allows the supply of air when the clean room is in negative pressure.

The filter used must be of sufficient thickness to allow effective air filtration. Typically, such a filter has a thickness of between 10 and 100 mm, preferably between 20 and 80 mm and, particularly preferably between 40 and 60 mm.

According to a first specific embodiment, the clean room is under depression, the clean room is then characterized in that:

- the opening associated with a filter is located on the roof of the clean room or in the upper part, preferably more than two meters from the ground, of one of the side partitions of the clean room; And

– the at least second opening, connected by an aeraulic connection means to a mobile FFU attached to the clean room, is located in the lower part, preferably less than one meter from the ground, of one of the side partitions of the White room.

According to a second specific embodiment, the clean room is under overpressure, the clean room is then characterized in that:

- the opening associated with a filter is located in the lower part, preferably less than one meter from the ground, of one of the side partitions of the clean room; And

- the at least second opening, connected by an air connection means to a mobile FFU attached to the clean room, is located in the upper part, preferably two meters or more from the ground, of one of the side walls of the room white, preferably another partition of the clean room than that of the opening associated with a filter.

According to a particular embodiment, the clean room according to the invention can comprise two openings each associated with a filter, one of which is closed off depending on whether one chooses to place the clean room under overpressure or under depression.

The filtration and ventilation units are known in the art under the name of FFU (Fan Filter Unit). They consist of an air overpressure means and at least one filter.

The means of overpressurizing the air are well known and include fans and turbines in particular. Preferably, such a means of pressurizing the air is a turbine.

Typically, the means for overpressurizing the air of the mobile FFU of the clean room according to the invention is able to allow the suction of air in the FFU and its evacuation with an operating flow rate of between 200 and 5000 m ³ /h, preferably between 500 and 2000 m ³ /h.

In the context of an overpressure clean room, the air overpressure means of the mobile FFU makes it possible to generate an overpressure of between 3 and 50 Pa (compared to the outside of the clean room), to preferably an overpressure of between 5 and 30 Pa (relative to the outside of the clean room) and, in a particularly preferred manner, an overpressure of between 10 and 20 Pa (relative to the outside of the clean room).

In the context of a clean room in depression, the means of overpressurizing the air of the mobile FFU makes it possible to generate a depression of between 3 and 50 Pa (compared to the outside of the clean room), to preferably a depression of between 5 and 30 Pa (relative to the outside of the clean room) and, in a particularly preferred manner, a depression of between 10 and 20 Pa (relative to the exterior of the clean room).

In connection with the at least one filter of the mobile FFU, it must have sufficient thickness to allow effective air filtration. Typically, such a filter has a thickness of at least 8 mm, preferably at least 10 mm and, even more preferably, at least 15 mm.

Alternatively, such a filter may or may not be formed from a superposition of several layers of the same material or of different materials. By way of example of a superposition of at least two layers, preferably of at least three layers or four layers and, even more preferably, of at least five or six layers.

Advantageously, the layer or layers of material forming the filter have a linear or V-shaped profile so as to increase the filtration surface.

According to a particular embodiment, said at least one filter is a high-efficiency air filter of the HEPA type. By HEPA filter is meant a device capable of filtering, in one pass, at least 99.97% of the particles with a diameter greater than or equal to 0.3 μm.

Advantageously, the mobile FFU unit further comprises an ionizer.

Typically, such an ionizer can take the form of at least one corona effect plasma cell comprising a polarized electrode substantially in the shape of a needle and a ground electrode, placed opposite the polarized electrode, comprising a cylinder substantially centered on the polarized electrode and a substantially planar porous film perpendicular to the polarized electrode. By way of example, such an ionizer is described in European patent application EP3613264 A1.

Such an ionizer is thus able to generate a plasma that the air flow would cross, which made it possible to electrically charge the particles present in the air so that they are retained in at least one electrostatic filter.

Preferably, the mobile FFU unit further comprises an electrostatic filter associated with the ionizer.

Such an electrostatic filter is typically made of mineral material such as glass or ceramic, and particularly preferably of fiberglass.

Such a filter is able to retain the ionized particles in order to allow their degradation by reaction with the ozone created by the ionizer.

Preferably again, the mobile FFU unit further comprises a catalyst associated with the ionizer.

Such a catalyst capable of decomposing the ozone produced by the ionizer can be chosen from activated carbon, zeolite or manganese oxide (MnO ₂ ). Indeed, these materials are able to allow rapid decomposition of ozone and nitrogen oxides at room temperature. Such a catalyst preferably takes the form of a honeycomb substrate, for example aluminum, which is coated with manganese oxide.

Advantageously, such a honeycomb substrate should have a thickness of at least 10 mm to be sufficiently effective in neutralizing ozone.

As a mobile FFU, it is possible to choose, for example, a mobile device as described in the PCT international application WO 2005/025711.

Preferably, the mobile FFU will be PLASMAIR GUARDIAN, PLASMAIR SENTINEL, HEPA GUARDIAN or HEPA SENTINEL from AIRINSPACE.

The clean room according to the invention also comprises at least one particle counter. Advantageously, such a particle sensor is able to determine the concentration of particles present in the air of the clean room. Particle sensors that can be used in a clean room according to the invention are well known to those skilled in the art, and generally make use of the properties of light scattering. Even more advantageously, the particle sensor according to the invention is able to determine the concentration of particles having a size greater than or equal to 5 μm in the air of the clean room. However, and according to other particular embodiments, the clean room according to the invention may comprise at least one particle counter capable of determining the concentration of particles of different sizes, for example having a size greater than or equal to 0.1 µm, 0.2 µm, 0.3 µm, 0.5 µm, 1 µm, 2.5 µm, or even 10 µm.

The clean room according to the invention advantageously comprises a central processing unit connected to the at least one particle counter, which is able to process the information read by said at least one particle counter.

According to a preferred embodiment, the processing of the information carried out by the central processing unit consists of determining the class of particulate cleanliness of the air in the clean room according to the reference system defined in the ISO 14644-1 standard. .
Thus, if the concentration of particles having a size greater than or equal to 5 µm is less than 293,000 particles/m ³ of air but greater than 29,300 particles/m ³ of air, the cleanliness of the air in the room white will be of ISO class 9. If the concentration of particles having a size greater than or equal to 5 µm is less than 29,300 particles/m ³ of air but greater than 2,930 particles/m ³ of air, the cleanliness of the the air in the clean room will be ISO class 8. If the concentration of particles having a size greater than or equal to 5 µm is less than 2,930 particles/m ³ of air but greater than 293 particles/m ³ of air, the cleanliness of the air in the clean room will be ISO class 7. Finally, if the concentration of particles having a size greater than or equal to 5 µm is less than 293 particles/m ³ of air, the of the clean room will be of ISO class 6. The definition of the particle classes according to the maximum admissible concentration (in particles pa r cubic meter) equal to or greater than a particular size is given in Table 1 below.

Classification number Maximum permissible concentrations (particles/m ³ of air) of particles of a size equal to or greater than that given below ISO(N) 0.1µm 0.2µm 0.3µm 0.5µm 1µm 5µm ISO class 1 10 ISO class 2 100 24 10 ISO class 3 1,000 237 102 35 ISO class 4 10,000 2,370 1,020 352 83 ISO class 5 100,000 23,700 10,200 3,520 832 ISO class 6 1,000,000 237,000 102,000 35,200 8,320 293 ISO class 7 352,000 83,200 2,930 ISO class 8 3,520,000 832,000 29,300 ISO class 9 35,200,000 8,320,000 293,000

Advantageously, the clean room according to the invention will also comprise at least one user interface preferably taking the form of a touch screen, whose position is ideally located next to the entrance door of the clean room and whose height allows easy consultation by an operator. Such an interface allows the operator to have a visual follow-up of the programmed and current operating parameters of the clean room. Now, it may also include an interface for manually configuring clean room settings, including a touchscreen LCD with navigation buttons. In a particularly advantageous way, the user interface is connected to the central processing unit which transmits to it in real time the class of particulate cleanliness of the air in the clean room according to the reference system defined in the ISO 14644-1 standard.

The clean room may also include other particle counters able to count particles of different sizes, for example to count particles having a size greater than or equal to 1 µm, or even 0.5 µm, 0.3 µm 0, 2µm, 0.1µm. In the event that such sensors are present, the central processing unit would be able to take into account this additional data to refine the determination of the class of particulate cleanliness of the air in the clean room according to the reference defined in the standard. ISO 14644-1.

According to a particular embodiment, the user interface of the clean room according to the invention emits a signal linked to the compliance of the level of particles in the clean room with respect to a set level. Advantageously, said signal related to the conformity of the level of particles emitted by the user interface of a clean room according to the invention is a visual and/or sound signal. Thus, if the particulate cleanliness class of the air in the clean room according to the invention differs from the setpoint particulate cleanliness class, the user will be notified.

The clean room may also include at least one sensor capable of measuring the quality or certain characteristics of the air within the clean room. Non-exhaustively, the at least one sensor can be a volatile organic compound (VOC) sensor, a carbon dioxide sensor, a carbon monoxide sensor, a dioxygen sensor, a temperature sensor or even a temperature sensor. 'hygrometry. Such sensors are connected to the central processing unit.

According to another particular embodiment, the clean room according to the invention also comprises at least one pressure sensor located inside said clean room, and at least one pressure sensor located outside said clean room , said sensors being connected to the central processing unit. In this case, the central processing unit is advantageously able to calculate the measured pressure difference dP between the inside and the outside of the clean room.

Thus, the cleanroom user interface can also display the measured pressure difference dP between the inside and the outside of the cleanroom calculated by the central processing unit, but also the temperature of the cleanroom, the operating flow rate of the air treatment and filtration unit and at least one signal related to the compliance of the measured pressure difference dP between the interior and exterior of the clean room with a set value. This at least one signal related to the conformity of the measured pressure difference dP between the inside and the outside of the clean room with a set value can be of different natures. This may be a first signal S0 if the measured pressure difference dP is equal to the setpoint value or differs from it by up to 2 Pa. Such a signal S0 may for example be a green light. It can be a second signal S1 if the measured pressure difference dP differs from the set value by more than 2 Pa up to 5 Pa. Such a signal S1 can for example be an orange light. It can also be a third signal S2 if the measured pressure difference dP differs from the set value by more than 5 Pa. Such a signal S2 can for example be a red light possibly accompanied by an audible warning to warn the user of the difference between the measured pressure difference dP and the setpoint.

According to another particular embodiment, the central processing unit of a clean room according to the invention is also connected to a memory, for example RAM bars, capable of recording the variations of the various parameters measured over time. . Such a memory advantageously allows the production of a "black box" type log allowing optimal traceability of the different parameters of the clean room.

Advantageously, such a sensor transmits the measurements that it takes to the microcontroller capable of controlling the operation of the mobile FFU unit, in particular when the measured values cross a predetermined threshold value.

Typically, the clean room according to the invention comprises an electrical box connecting all the electrical equipment of the clean room, which electrical box is connected to a general power supply.

The clean room according to the invention can also include multiple additional equipment. By way of example, we can cite lighting elements, electrical connections, gas connections (oxygen, air, etc.), heating means or even windows.

Claims (10)

A clean room having at least one volume delimited by partitions associated with each other and fixed to the ground and, optionally, to at least one wall of a building, comprising:
• At least one entrance door;
• At least one filtration and ventilation unit (FFU);
• At least one opening associated with a filter;
characterized in that it further comprises a system for instantaneously determining the level of particles within it, which system comprises:
1) At least one particle counter,
2) At least one user interface capable of displaying the instantaneous level of particles within the clean room; And
3) At least one central processing unit connected to the particle counter and able to process the information detected by this sensor to enable its display on the user interface. The clean room according to claim 1, characterized in that the at least one user interface displays the instantaneous level of particles within the clean room according to the classification defined in the ISO 14644-1 standard. The clean room according to any one of claims 1 or 2, characterized in that the particle counter is capable of measuring the concentration of particles having a size greater than or equal to 5 µm. The clean room according to any one of claims 1 to 3, characterized in that it further comprises at least one pressure sensor located inside the clean room, and at least one pressure sensor located outside outside the clean room, said sensors being connected to the central processing unit. The clean room according to any one of claims 1 to 4, wherein the user interface displays at least the measured pressure difference dP between the inside and the outside of the clean room, the temperature of the clean room, the flow rate operation of the air treatment and filtration unit and at least one signal relating to the compliance of the measured pressure difference dP between the inside and the outside of the clean room with a set value. The clean room according to claim 5, wherein the at least one signal relating to the conformity of the measured pressure difference dP between the inside and the outside of the clean room with a set value can be a first signal S0 if the measured pressure difference dP is equal to the set value or differs from it by up to 2 Pa, a second signal S1 if the measured pressure difference dP differs from the set value by more than 2 Pa up to 5 Pa, a third signal S2 if the measured pressure difference dP differs from the set value by more than 5 Pa. The clean room according to any one of claims 1 to 6, further comprising a memory, for example RAM bars connected to the central processing unit, capable of recording the variations of the various parameters measured over time. The clean room according to any one of claims 1 to 7, characterized in that when it is able to operate in depression, that is to say that the pressure inside the clean room is lower than the atmospheric pressure. The clean room according to any one of Claims 1 to 7, characterized in that when it is capable of operating under overpressure, that is to say that the pressure inside the clean room is greater than the atmospheric pressure. The clean room according to any one of claims 1 to 9, characterized in that the user interface emits a signal linked to the conformity of the level of particles in the clean room with respect to a set level, preferably a visual signal and/or sound.