Calculation of operating modes for disinfection robots

The Santec Extended (Santec E) robot safely and autonomously disinfects any type of enclosed space. Driven by an autonomous navigation system, Santec activates tested collision avoidance technology (LIDAR SLAM) and many unique safety features. This includes visual warnings and human (or animal) detection with automatic shutdown of UVC lamps to minimize the likelihood of accidental human exposure.

Main technical characteristics of Santec E disinfection robot

? Accuracy of navigation, no more - 0.05m;

? Speed, max - 1.5 m / s;

? The minimum distance to detect obstacles - 2 m;

? Minimum distance for PIR sensors - 5m (for detecting people and other living beings in order to control UV exposure and ensure safety);

? Battery capacity - DC 24V 35Ah;

? Working time of the robot, full power ~ 2h (moving, USx6, UVCx6)

? Working time of the robot, not full power ~ 4 hours (moving, USx6 or UVCx6)

? Working time of the robot, not full power ~ 6 hours (moving, USx6)

? Working time in standby mode ~ 48 hours;

? Product weight - 70 kg;

? Permissible floor slope, max - 5 degrees;

? Intelligent self-charging with positioning at the charging station;

? Web interface for controlling the robot, customizing modes and settings.

Robot operating modes:

1.UV lamps: 2 pcs. / 4 pcs. / 6 pcs.;

2. Ultrasonic (US) dry fog generator: 2 pcs. / 4 pcs. / 6 pcs.;

3. Combinations of these modes.

Parameters of UV irradiators:

The number of ultraviolet groups - 6 short-wave UV-C lamps;

Radiation wave length - 253.7 nm;

The total power of the irradiators - 216W (36W x 6 lamps 1200mm);

Automatically turn off when a person approaches a distance of up to 5 m;

The effectiveness of bactericidal irradiation, no more - 3 m;

Irradiation diagram - 360 degrees.

Spraying parameters by ultrasonic (US) generators:

The amount of fog is - 2.5 L/h,

Fog particle size, no more - 10 microns

Number of ultrasonic generators for fogging - 6;

Processing area for 2 hours - 1500 m2;

Air processing volume for 2 hours - 1000m3;

Container with disinfectant - 5.4 liters (refilled through a funnel, located in the inspection hatch).

Disinfectant used (recommended):

Hydrogen peroxide (H2O2).

Other specifications:

? Standby current - <0.5A;

? Intensity of UV radiation - 270 μW / cm2 (measurements at a distance of 1 m)

? Service life of the device when used in a combined mode, not less than 15,000 hours (8 years of daily use);

? LIDAR SLAM technology;

? Differential drive BLDC motor 25 W x 2;

? WxLxH - 600x800x1700;

? Rated power - 500 watts.

3 year warranty. Service / technical support 24 | 7

Advantages of the Santec E disinfection robot

The disinfection robot is an effective disinfection tool for public premises, educational institutions, medical institutions, etc. The robot implements two of the most effective and recognized by the Ministry of Health and the WHO methods of disinfection, a number of experiments and calculations were carried out, which confirmed the feasibility of the selected methods and technical characteristics of power, safety, etc.

The robot is designed so that the main flow of energy falls on the height of the most active area of human use - about 85 cm. This height is typical for the vast majority of surfaces of tables, backs of chairs, elevator buttons, door handles, water taps, furniture handles, and the like.

Ultrasonic Disinfectant Dispenser - Santec E

The Santec E robot is equipped with a so-called dry fog function. This function shows very high efficiency dealing with viruses and bacteria when sanitizing premises. Hydrogen peroxide is recognized by the Ministry of Health of Ukraine and WHO and recommended as one of the safest and most effective bactericidal agents for humans.

Ultrasonic fog generator - considered the most effective, such humidifiers create fog by knocking out small droplets of liquid (H2O2) from the liquid surface using ultrasonic vibrations received by a piezoelectric emitter. The fog is carried through the volume of the room by natural air currents or by force (for example, using fans installed in the Santec E robot). A certain amount of fog settles on the surface of the room and covers them in a dense layer. Thus, a bactericidal effect is achieved. The use of an ultrasonic generator makes it possible to obtain hydrogen peroxide fractions less than 10 microns in size, contributes to uniformity, high density and maximum coverage with a thin layer of this effective and safe disinfectant of surfaces in the room.

Hydrogen peroxide

According to WHO, agents based on hydrogen peroxide effectively disinfect even at minimal concentrations and without negative impact on the human body. They have detergent, deodorant, moisturizer, emulsifier properties and biodegradable into oxygen and water.

The use of disinfectants based on hydrogen peroxide in the form of microparticles of the so-called dry fog is more effective than spraying it through, for example, a spray bottle with a droplet size of about 0.1 - 0.5 mm due to a denser and more effective surface coating.

Ultraviolet irradiator - Santec E robot

For example, let's calculate the disinfection time for a typical room with an area of 100 m2.

S = 100m2 (by floor)

Ssum = 320m2 (floor, ceiling and walls)

W = 10 m

L = 10 m

H = 3m

V = 300 m3

Room disinfection with the Santec E robot

Let's set up the robot to work through passing points on the map of the room, arrange the points in such a way (we will form the route of the robot) so that the robot moves with an interval of 1 meter and “scans” all the rooms with this grid. Or, more simply, drives over the entire surface of the floor with the maximum density of the trajectory lines.

Then the robot will need to travel about 80 m. At an average work speed of 0.8 m / s, this work will take about 1.5 minutes of time.

We will take into account possible obstacles and room features that can lead to an increase in the trajectory, a decrease in speed at some intervals of the path, thus increasing the processing time up to two times, which will be approximately 3 minutes.

Now let's calculate the required power of UV radiation to achieve the standard radiation dose, it is necessary to neutralize 99, 99% of bacteria and viruses on surfaces in the room.

According to the specification, the Santec E, the total power of UV radiation is 36W x 6 lamps = 216W. Let's take into account that no matter how we install the lamp, we will never get 100% of the power directed to the irradiated object - this indicator is always reduced due to the reflector or structural elements, protective mesh, etc. It is popular and common practice to account for 70% of the energy emitted by lamps.

Then the total power of the irradiator will be 216 x 0.7 = 151 W. P = 151W

Let's calculate the irradiation power per m2:

Wip = P / Ssum = 151/320 = 0.47 W/m2

Let's calculate the bactericidal dose:

J = 0.47 x 180sec = 85 J/m2.

According to the standard for public premises, a bactericidal dose of 50 J/m2 is required for bactericidal treatment with the result of neutralizing viruses and bacteria at the level of 99.9% of the original.

Our indicator with a margin of more than 50% satisfies the standard. It should be noted that the calculation was conducted on basically laboratory conditions, when we process the surfaces of the floor, ceiling and all the walls.

In a real experiment, we need to take into account that the area of the surfaces that need to be processed is 2-3 times larger, we also need to take into account the zones that can be hidden or shadow covered and cannot be processed at the estimated time limit, and so on.

Thus, we recommend increasing the processing time limit to 2-3 times, creating denser routes for the robot and maximizing the advantages of a mobile autonomous irradiator compared to a stationary wall-mounted irradiator.

For example, for the considered room, the robot should cover two or three circles of processing, or the speed should be reduced by two or three times, which will allow us to completely and with high efficiency neutralize viruses and bacteria in the room in about 10 minutes.

Let's consider the option of using a less powerful emitter, for example 24W in the same conditions.

The total power of the illuminator will be 24 x 0.7 = 16.8W. P = 16.8W (reflection and diffusion by a protective grid).

Let's calculate the irradiation power per m2:

Wirr = P / Ssum = 16.8 / 340 = 0.049 W/m2

Let's calculate the bactericidal dose:

J = 0.049 x 180sec = 8.82 J/m2.

The calculation shows that with a decrease in the irradiation power, we received an irradiation dose 6 times lower than the required standard dose. Such a dose will definitely not destroy viruses and bacteria, and in some cases can even activate and stimulate the growth of microflora.

If we still want to try to achieve a germicidal dose level of 50 J/m2, we can try to increase the treatment time by 10 times, and get about 88 J/m2, which meets the standard for public premises. Further, in order to get closer to real conditions, it is recommended to increase the processing time by another 2-3 times (taking into account shadows, dust, moisture, etc.), then for an irradiator with a power of 24W we get a processing time of about 3 minutes x 10 x 3 = 1.5 hours.

An important feature of the use of UV irradiation should be emphasized. According to the regulatory documents, the effectiveness of disinfection under such conditions practically cannot be achieved for any duration of irradiation, and an insufficient value of the UVC flux (subbactericidal dose) can stimulate the growth of microflora.

According to the calculation, using a 24W UV illuminator is ineffective, or even counter-effective.

Summarizing on UV exposure, we can say:

1. It is impractical and inefficient to use irradiators that do not provide an energy concentration higher than 0.1 W / m2;

2. The combination of the work of the UV irradiator and the sputtering of hydrogen peroxide (H2O2) simultaneously - leads to the appearance of active free oxygen radicals in the form of OH, which are one of the most powerful oxidizing agents and are very aggressive towards microorganisms and other organic and bioorganic contaminants. We get a synergistic effect of UV exposure and an active oxidizing agent - these two factors disproportionately increase the bactericidal efficiency in sanitizing premises.

You can see how H2O2 decomposes to OH under the influence of UV irradiation in the video below.

Santec E disinfection robots do not use closed-type UV recirculatory irradiators due to their proven low efficiency and the corresponding recommendations of the Ministry of Health of Ukraine.

Let's consider a very popular now, but ineffective and not recommended by the Ministry of Health of Ukraine and WHO disinfection method - closed-type UV recirculatory irradiators.

Ultraviolet recirculatory irradiators is a device for air disinfection, consisting of a tube about 1 m long with one or two ultraviolet lamps inside and fans.

Air enters the device from one side and exits from the other. Inside the recirculatory irradiators, the air absorbs ultraviolet radiation. The required dose of ultraviolet radiation to inactivate an infectious aerosol in a closed room is 10,000 μW/cm2, (the norm for surgery operating rooms is 3 times higher than the norm for public premises) with an average time of air passing through the tube up to 5 seconds. If we check the ultraviolet load inside the recirculatory irradiator using an ultraviolet radiometer, then we will register a dose of 200-500 μW/cm2. That is, in order to disinfect the air in a closed room, it is necessary that one pathogen enters the recirculatory irradiator from 20 to 50 times.

So, for high-quality disinfection of air in a room of 20 m2, 20-30 recirculatory irradiators are needed. A recirculatory irradiators alone cannot cope with this.

Also, for effective operation, the ultraviolet recirculatory irradiators must be treated with 70% alcohol on a monthly basis. However, the closed-type irradiator design does not allow UV lamps to be processed.

In short, it is impractical to use closed recirculatory irradiators in public premises or hospitals. Do not buy or use them, because closed-type irradiators are physically incapable of effectively disinfecting a room.