RU2731265C1 - Aerosol method of disinfection of ventilation systems - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention can be used in medicine, namely in disinfectology, and is intended for prevention of outbreaks of infectious diseases. Method involves injection of the amount of a disinfectant emulsion in range of 5 to 25 mcm, containing a film-forming agent, into the process holes of the ventilation channels in the absence of air influx. Aerosol of disinfectant solution is obtained from 4.0 % disinfectant solution of "Desargent" by means of atomizer designed for dispersion of 5–25 mcm and capacity of 30 ml/min, air supplied from compressor at 6 atm is used for dispersion, air is supplied to the gun with the nozzle through a flexible spiral air duct.

EFFECT: method provides improved quality of disinfection due to uniform distribution of the disinfectant along the inner surface of the air duct of the ventilation system.

1 cl, 2 tbl

Description

The invention relates to medicine, namely to disinfectology, and is intended for the prevention of outbreaks of infectious diseases.

Currently, the aerosol disinfection method is successfully used to disinfect air and surfaces of various types of premises due to its significant advantages over other disinfection methods. The large-scale use of aerosol disinfection of ventilation systems has occurred due to innovative solutions, including new designs, namely:

- installation of external suspended ventilation systems from metal structures;

- the ability to access any area of the inner surface of air ducts (requirements of GOST R EN 1377-2007 for design);

- possibility of processing without preliminary dismantling of air ducts and units.

Also, the widespread introduction of aerosol disinfection into practice contributed to the entry into the market of a large number of aerosol generators, including those registered as medical products.

At the moment, several methods of disinfection of ventilation systems have been proposed without their accompanying dismantling. With all its indisputable merits, each of the methods does not fully contribute to the achievement of the set goal.

One of the methods according to patent RU 2257228 (2005) was developed for the case when the surfaces of the air ducts can be disinfected by supplying a disinfectant solution in the form of an aerosol to a mechanically driven inlet ventilation at the level of the air intake. Further, the aerosol is pulled by the air flow through the air ducts until signs (traces) of disinfectants appear at their outputs. Disinfectant consumption is also 50-150 ml per sq. m. surface of air ducts. For aerosol production it is proposed to use mechanical and electrical aerosol generators. When testing this method, it was found that 90% of the aerosol is retained at the first bends of the air duct. At the final outlets of the supply ventilation, only traces of the odor of the disinfectant were detected. Traces of the disinfectant itself (in the form of drops or smudges) were not observed. When controlling the quality of disinfection - by using test cultures in the area of the outlet vents - positive results were obtained, thus the goal of the disinfection measures was not achieved.

With the method of disinfection of ventilation and air conditioning systems, which is described in patent RU 2519668 (2010), the same disadvantages are noted as in the previous one. The only difference is that the supply of disinfectants in the form of an aerosol is carried out into the outlets of the supply ventilation system. In this case, the supply ventilation is transferred to the exhaust mode by changing the direction of rotation of the fan impeller. Changing the direction of the air flow can also be achieved by changing the connection points of the suction and discharge nozzles on the fan, or by using portable vacuum units with plugs.

In patent RU 2574910 (2016), it is proposed to carry out disinfection by placing a device (for example, a cartridge) at the inlet or outlet of the ventilation duct containing a disinfectant that evaporates under the action of an air flow passing through the ventilation duct. Many questions arise about this method of disinfection. First, it is difficult to set a constant, controlled and predictable rate and level of evaporation of the disinfectant (air saturation with the main active ingredient), since these processes are clearly influenced by temperature, humidity and atmospheric pressure. Thus, it becomes impossible to maintain the optimal dosage of AI per unit area to ensure the biocidal effect. In addition, the presence of people in the treated premises is problematic due to the threat of negative effects of constant and, possibly, increased concentrations of the disinfectant. Secondly, from the description of this method it follows that a column of air at a distance of only 30 cm from the ventilation grill is exposed to direct disinfection. Therefore, “disinfection of the ventilation system, including disinfection of the ventilation duct” does not occur. Finally, there is no description of the results of the verification tests confirming the quality of the processing performed.

The closest analogue is the method described in patent RU 2625748 (2017).

For disinfection of ventilation systems, first, in the absence of air flow, an aerosol of a disinfectant is injected into the technological openings of the ventilation ducts in a calculated amount. As a disinfectant, a disinfectant emulsion containing a film former is taken. The aerosol is obtained using an aerosolizing generator, setting the dispersion mode of the disinfectant emulsion to 5-25 microns. After treatment with the specified aerosol, the exposure is carried out with closed technological openings for the time required for the formation of a disinfectant emulsion film on the inner surface of the ventilation ducts. At the end of the exposure, the remnants of the finely dispersed phase of the aerosol are removed by blowing the ventilation ducts with air in the usual mode.

Aerosol treatment of ventilation ducts is carried out with disinfectants "Desitol S-01" and "Biopag-D" containing a film former, which are fixed on the walls of the air ducts in the form of a polymerized biocidal film. Aerosol is injected into the inspection holes in a calculated amount for each section with the ventilation system turned off.

To obtain an aerosol of a disinfectant for aerosolizing air ducts, use any generator capable of generating particles of various sizes, including from 5 microns to 25 microns and having a remote nozzle with a nozzle for insertion into a semi-oval inspection hole measuring 20x10 cm. Emulsions are used as a disinfectant. or solutions of disinfectants containing film-forming agents. The concentration of the active substance of the disinfectant used to obtain the solution is calculated according to the Instructions for use of the drug, namely, according to the amount of the required active substance per 1 sq. m of the treated surface in 25 ml of solution. The aerosol is injected into the technological holes for a time equal to the amount of the disinfectant emulsion divided by the generator output with the ventilation system turned off. The exposure of the sprayed aerosol of the emulsion of the disinfectant is carried out with closed technological holes for the time required for its film formation. Mostly, the exposure time is no more than 2 hours, during which 90% of the medium-dispersed aerosol of the disinfectant emulsion settles on the walls of the air duct and is fixed on it in the form of a polymerized biocidal film. Then, with closed technological openings, air is blown through the air duct to free the inner cavity of the main air ducts, as well as ventilation chambers, air intake shafts, heating and irrigation chambers from the remaining fine suspended aerosol particles.

The known method has the following disadvantages:

1. Labor intensity and danger of manipulating the above aerosol generators when working at a height of 3-4 m using support structures (ladders, stepladders);

2. Formation by aerosol generators of the ULV type of a directed flow of particles with high kinetic energy, having sizes of 0.5 microns and larger, including rapidly settling coarse particles with a size of more than 25 microns, do not allow achieving a uniform distribution of the disinfectant on the surface of the air ducts.

Thus, the search for a more perfect method of disinfection of ventilation systems remains an urgent topic for the correct choice of a treatment method that guarantees disinfection of the ventilation system and ensures the safety of performers and people around them.

The objective of the invention is to further expand the arsenal of effective and safe methods of disinfection of air ducts of the ventilation system using aerosols of disinfectants with minimal costs of disinfectants and significant relief of the work of disinfectants.

The technical result is to improve the quality of disinfection due to the uniform distribution of the disinfectant over the inner surface of the air duct of the ventilation system.

A method of disinfection of systems by means of aerosol treatment of the inner surface of ventilation ducts is claimed, including the injection of a calculated amount of a disinfectant emulsion with a dispersion of 5 to 25 microns, containing a film former, into the technological openings of ventilation ducts in the absence of air flow, characterized in that the aerosol of a disinfectant solution is obtained from 4.0% disinfectant solution of the brand "Desargent" by means of a nozzle, air supplied from a compressor at 6 atm is used for dispersion, air is supplied to a gun with a nozzle through a flexible spiral air duct.

To solve the problem, reference material was studied. As a result, it was found that according to the instructions for the use of disinfectants for aerosol disinfection, preparations of almost all chemical groups are used and each has its own regime (tab. No. 1).

Disinfectants Tab. # 1.

Name of the drug DV Form of preparation Instructions Application mode Deo-chlorine lux Sodium salt DCCC Tab. No. 18/13 of 2013 Use of generators of fine aerosols with a particle size of 1 micron, 10 ml / m³. Consumption rate according to the instructions for the device Deo-bacter plus HOUR 18%
Isoprpanol 5.0% Solution No. 34/17 of 2017 Aerosolization is carried out with aerosol generators, the consumption rate is in accordance with the instructions for use of the generator Betadez HOUR 12% Solution No. 3/11 of 2011 Consumption rate 10 ml / m³. Suitable for irrigation and immersion. Appropriate technical devices are used Desargent Hydrogen peroxide 6% Solution No. 20/12 of 2013 The Ultrasprayer nebulizers are used (see below). Nakolysis Hydrogen peroxide 6% Solution Use the device "Nokosprey" (see below) "Cartridge GLOSAR * 400" Hydrogen peroxide 5-6% Solution No. 1/2015 of 2015 GLOSAIR ™ 400 automatic system * Disinfectant "Aeron" Polyhec-Sametyl-enguanidina hydrochloride (0.16%) and didecyl-dimethyl-ammonium chloride (0.03%) Aero-ash cylinders
75-750 ml No. 43 of 2012 A 1000 ml bottle is sufficient to treat air with a volume of
less than 750 m³, one 50 ml cylinder is enough to treat air with a volume of at least 37.5 m³, OPTIMAX prof Amine 5.0% Solution No. D-19/09 of 2009 Disinfection of air ducts of ventilation systems is carried out by the method
irrigation (fine atomization)

According to the instructions for the use of disinfectants, the modes of aerosol disinfection of air, but not the inner surfaces of the air ducts of the ventilation system, are determined.

To obtain aerosols, equipment of varying degrees of complexity is used - from hydraulic control panels to aerosol generators with remote control. The size of the generated aerosol droplets can vary from finely dispersed 0.5 - 5 microns to coarsely dispersed 100 microns (tab. No. 2).

Aerosol generators Tab.№2

Generator name Manufacturer country Disinfectants used Aerosol size, μm Consumption, ml per m³ The presence of a remote nozzle (nozzle) Aerosol disinfection device Nocospray * France Nokolysis in a cartridge
(solution 6% H2O2, AgNO3) five 1 - Automatic system GLOSAIR ™ 400 ** USA, France Solution 5% Н2О2, Ag, H3PO4 in a cartridge 8-12 6 - Aerosol spray "Ultrasprayer R-60M" *** Russia Desargent ready-made solution (solution 6% H2O2, Ag) 1-5 3 - Mobile hygiene center (MGC®) **** Russia All aerosol formulations 3.5-10
10-20
20-50
50-100 not installed - Centrifugal aerosol generator TsAG-Jet-2 Russia All aerosol formulations 2-30 not installed - Aerosol generator PRO-ULV 1035 USA All aerosol formulations 0.5-13.5 not installed Raster ULV Fogger India All aerosol formulations 5-10 ten - Longray 1680 Cold Fog Machine China All aerosol formulations 5-30 not installed - Cold fog generator OR-DP1 China All aerosol formulations 0-20 not installed - Cold Mist Generator Storm China All aerosol formulations 5-50 not installed - Cold fog generator ULV Tornado 10 South Korea All aerosol formulations 5-40 not installed - Cold Mist Generator
Airofog U-260 China All aerosol formulations 5-30 not installed Rulsfog TURBO ULV cold fog generator Germany All aerosol formulations 0.5-50 2

Registered as medical equipment

* - RZN 2016/3916 dated 01.04.2016

** - FSZ 2011/09052 dated 06/18/2014

*** - RZN 2014/1020 dated 09.09.2014

**** - RZN 2016/3908 dated 15.11.2016

From the above, it follows that in the conditions of intensive introduction and use of aerosol generators, on the one hand, and a wide variety of disinfectants, on the other hand, the difficult task of choosing the most optimal mode of the applied disinfectant and the generator used for disinfection of the ventilation system arises.

To fulfill the listed requirements, we used a set of equipment for an aerosol generator at the ventilation system stand, equipped with technological openings and inspection hatches of RD type tightly adjacent to them. The set of equipment for the aerosol generator includes a compressor for 6 atm., flexible spiral air duct with a length of 5 m, a painting gun with a nozzle with a capacity of 30 ml / min and generating an aerosol of 5-25 microns in size.

"Desargent" was used as a disinfectant (certificate of state registration No. RU.77.99.01.002.Е002883.11.10 dated 22.11.2010). The aerosol is injected into the technological holes for a time equal to the amount of disinfectant solution required for a given area, divided by 30 ml / min - the nozzle productivity. The amount of disinfectant solution for making an aerosol is determined by multiplying the area of the duct in sq. m per 25 ml of disinfectant solution. In a closed space with aerosols with a particle size of 5 microns to 25 microns, the effect of diffusion (sticking) with the surface of the air ducts is triggered. As our studies have shown, with particles larger than 25 microns (coarse aerosols), droplets are formed that do not provide volumetric aerosol distribution inside the air ducts of the ventilation system and, therefore, a uniform and continuous film of disinfectant emulsion does not form on the inner surface of the air ducts. When using an aerosol with a particle size of less than 5 microns (fine aerosol) it is also not possible to achieve the declared result, because Such an aerosol does not settle on the surface for a long time and the required disinfectant film does not form on the inner surface of the ventilation ducts. The exposure of the sprayed disinfectant aerosol is carried out with closed technological holes for the time required for its disinfection. Mainly, the exposure time is no more than 1 hour, after which, with closed technological openings, air is driven through the air duct to release the remaining fine suspended aerosol particles from the inner cavity of the air ducts.

The claimed set of essential features:

- an aerosol of a disinfectant solution is obtained by means of a nozzle designed for a fineness of 5 - 25 microns,

- for dispersion, air supplied from a compressor at 6 atm is used,

- air supply to the gun with a nozzle through a flexible spiral air duct

allows to obtain a new technical result, which is expressed with a minimum cost of disinfectants, a significant relief of the labor of disinfectants and an improvement in the quality of disinfection due to the uniform distribution of the disinfectant along the inner surface of the ventilation system duct.

This makes it possible to ensure the speed and efficiency of disinfection in the foci of mass infectious diseases transmitted by airborne transmission, especially in modern high-rise buildings and sports facilities.

The inventive method can be carried out using known methods, means and equipment, i.e. meets the criterion "industrial applicability".

The claimed method is illustrated by examples of specific implementation.

The tests of the proposed disinfection method were carried out on a block of two connected air ducts of the ventilation system made of galvanized steel. The study of bactericidal activity and effectiveness of disinfection was carried out in accordance with "R 4.2.2643-10. 3.5. Disinfectology. Methods of laboratory research and testing of disinfectants to assess their effectiveness and safety. Management "(approved by Rospotrebnadzor on 01.06.2010), clause 5.1., Pp. 5.1.3.5. Staphylococcus aureus bacteria were used as test cultures.

In two technological (inspection) holes alternately injected medium-dispersed aerosol of 5-25 microns in size, which was obtained from a 4.0% solution of disinfectant brand "Desargent" using a nozzle at 30 ml / min. The exposure time is 1 hour from the moment the aerosol injection is completed and the last technological hole is closed.

According to instruction No. 20/12 on the use of disinfectant "Desargent" for bacterial infections, air ducts are disinfected with 0.5-1.0% solutions at a rate of 100 ml per square meter. m. When testing the proposed method, the consumption of disinfectant is 25 ml per 1 sq. m., i.e. the concentration of the solution in the antibacterial regime should be 4 times higher - 2.0-4.0%.

Disinfection efficiency tests were carried out by applying the internal sections of the ventilation ducts through the test culture holes on two 10 cm x 10 cm areas. The control washes were taken from the sites of bacterial cultures application after 1 hour. Samples were examined in an accredited laboratory in accordance with MUK 4.2.2942-11. 4.2. Control methods. Biological and microbiological factors. Methods of sanitary and bacteriological research of environmental objects, air and sterility control in medical institutions. Methodical instructions "(approved by Rospotrebnadzor on 15.07.2011). Staphylococcus aureus was not found in the test results of control washings.

Operational tests have confirmed the high efficiency of the claimed aerosol method for disinfecting the inner surface of air ducts of ventilation systems, significantly facilitating the labor of disinfectants, as well as reducing prices due to simplification of equipment for generating aerosol.

Claims (2)

A method of disinfection of ventilation systems by aerosol treatment of the inner surface of ventilation ducts, including the injection of a calculated amount of a disinfectant emulsion with a dispersion of 5 to 25 microns, containing a film former, into the technological openings of ventilation ducts in the absence of air flow, characterized in that the aerosol of a disinfectant solution is obtained from 4.0% disinfectant solution of the brand "Desargent" by means of a nozzle, air supplied from a compressor at 6 atm is used for dispersion, air is supplied to a gun with a nozzle through a flexible spiral air duct.