RU2279806C2 - Method and device for disinfecting loose material - Google Patents

Abstract

FIELD: preservation edible seeds.

SUBSTANCE: method comprises affecting the product by ultraviolet radiation, during which the orientation of several particles is changed with respect to the radiation source during its movement. The wavelength of the ultraviolet radiation used ranges from 185 to 400 nm, pulse duration ranges from 1 ms to 10 ms, and density of pulse radiation power at the product to be treated is at least 100 kW/m². The device comprise charging unit, source of ultraviolet radiation, means for transporting the product to be treated, and unit for discharging. The source of the ultraviolet radiation is made of a pulse gas-discharging lamp connected with the power source with accumulator, charging device, and ignition block.

EFFECT: improved quality of disinfection.

2 cl, 3 dwg, 1 tbl

Description

The invention relates to techniques and technology for the disinfection of bulk products, in particular bulk food, grain, seeds, combined feed of poultry and animals and other agricultural products, ingredients of pharmacological and homeopathic preparations, etc.

Radiation sterilization methods are known that use various ionizing radiation (x-ray, gamma radiation) and fundamentally solve the problem of disinfection of granular media, which with regard to food and medicinal products cannot be considered satisfactory, since they cause deep volumetric modifications of the chemical structure of the treated objects and lead to operating time side chemical compounds with specific biological properties.

Thermal methods of processing bulk food products are also known, providing for the heating of the processed product in various ways, for example, microwave radiation (RF patent No. 2031585, class A 23 B 9/04). Thermal methods in their various modifications are very energy-intensive, require expensive equipment and do not always provide the necessary level of decontamination of the processed objects. In addition, during high-temperature processing of food products, a partial thermal degradation of many protein and other biologically relevant structures of the initial product inevitably occurs, which leads to a decrease in its consumer properties.

Currently, the most common are chemical methods for the disinfection of bulk products.

So, there is a known method of disinfecting bulk products, providing for a disinfectant effect on the processed product during its movement (RF patent No. 2081599, class A 23 B 9/32). The disinfecting effect of the known method is carried out by vapors of propionic acid.

A device for disinfecting bulk products is also known, comprising a loading unit, means for transporting the processed product, a means for disinfecting the processed product and the unloading unit (see ibid.).

The disadvantages of the known method and device, as well as any other varieties of chemical methods and devices for their implementation, are as follows.

The impact of any chemicals on agricultural products and the ingredients of various preparations is potentially dangerous, since various chemical reactions can be triggered, leading to a change in the physicochemical and biological properties of the processed products. Assessing the real danger of such changes, especially remote ones, is extremely difficult and far from always reliable. Residual quantities of the chemical in one form or another get into the final product. The risk of overdose during processing is very high. Chemicals usually have a significant aftereffect.

In addition, the known method and device, like most chemical methods, are selective with respect to the nature and condition of the processed product, i.e. for a specific type and condition of the product, in the general case, the selection of the appropriate chemical reagent and the mode of its application is necessary.

The objective of the present invention is to increase the degree of disinfection of bulk products, reducing the aftereffect and risk of overdose, ensuring versatility in the processing of various products.

The problem in part of the proposed method is solved in that the disinfecting effect is carried out by irradiating the processed product with ultraviolet radiation, while moving the processed loose product is produced with a change in the orientation of its individual particles relative to the source of ultraviolet radiation.

The problem is also solved by the fact that ultraviolet radiation in the wavelength range from 185 to 400 nm is used to irradiate the processed product.

The problem is also solved by the fact that for the irradiation of the processed product apply ultraviolet radiation with a continuous spectrum.

The problem is also solved by the fact that for the irradiation of the processed product using pulsed ultraviolet radiation with a pulse duration of radiation from 1 μs to 10 ms.

The problem is also solved by the fact that the density of the pulsed radiation power on the processed product is at least 100 kW / m ² .

The problem in terms of the proposed device is solved in that the means for disinfecting the processed product is made in the form of an ultraviolet radiation source connected to a power supply, and the means for transporting the processed product is made with the possibility of changing the orientation of individual particles of the granular product relative to the ultraviolet radiation source.

The problem is also solved by the fact that the source of ultraviolet radiation is made in the form of a discharge lamp containing a flask made of a material transparent to ultraviolet radiation and electrodes.

The problem is also solved by the fact that the bulb of the discharge lamp is made of quartz glass.

The problem is also solved by the fact that the bulb of the discharge lamp is filled with mercury vapor, and the power supply contains a starter and ballast resistance.

The problem is also solved by the fact that the bulb of the discharge lamp is filled with an inert gas, mainly xenon, or a mixture of gases, and the power supply contains an ignition device and a current source.

The problem is also solved by the fact that the bulb of the discharge lamp is filled with an inert gas, mainly xenon, or a mixture of gases, and the power supply contains an ignition device, a capacitive storage device and a charger.

The problem is also solved by the fact that the means for transporting the processed product is made in the form of a vibrating conveyor with an adjustable direction of vibrational vibrations, and the source of ultraviolet radiation is mounted above the conveyor.

The problem is also solved by the fact that the means for transporting the processed product is made in the form of a hollow drum rotating around its axis, and an ultraviolet radiation source is installed inside the drum coaxially or parallel to its axis.

The problem is also solved by the fact that the rotating drum is configured to adjust the angle of inclination of the axis of rotation.

The problem is also solved by the fact that the inner surface of the rotating drum is made with screw thread.

The proposed method and device are illustrated in graphic materials, in which Fig. 1 schematically shows the design of a device with a vibrating conveyor as a means for transporting the processed product, Fig. 2 is the same, in section AA in Fig. 1, Fig. 3 - the design of a rotary device with a rotating drum as a means for transporting the processed product.

The device for disinfecting bulk products contains a loading unit 1 in the form of a metering hopper, means for transporting the processed product in the form of a vibrating conveyor, which is a tray 2 mounted on shock absorbers 3. A scarf 4 is attached to the bottom of the tray 2, which ensures rigidity of the vibrating part of the conveyor and which has a vibrator 5 with an adjustable direction of vibrational vibrations.

One or more ultraviolet radiation sources 6 connected to the power supply unit (not shown in FIG. 1) are installed above the tray 2. The radiation sources 6 are structurally isolated from the means for transporting bulk product.

The unloading unit 7 serves to accumulate the processed product and can be made in the form of a receiving storage hopper.

The ultraviolet radiation source 6 is made in the form of a discharge lamp containing a flask of transparent material (usually a high-quality quartz with a short-wavelength transmission limit of about 185 nm, or doped quartz or uvole glass with a short-wavelength transmission limit of 220-230 nm) and electrodes.

The bulb of a gas discharge lamp may be filled with mercury vapor, in which case such a source of ultraviolet radiation is a conventional bactericidal lamp (low, medium or high pressure). Such a lamp is connected to a standard power supply unit (ballast), containing a starter and ballast inductance. The emission spectrum of a low-pressure mercury bactericidal lamp consists of several spectral lines, the most powerful of which corresponds to a wavelength of 253.7 nm, which provides the effect of disinfection. The lamp operates in continuous mode with a low intensity of bactericidal radiation. The power of such lamps reaches hundreds of watts.

The bulb of a gas discharge lamp can also be filled with spectrally pure inert gases (xenon, krypton, argon, etc.) or a mixture of gases at a pressure of several atmospheres. Such lamps provide a continuous combustion mode, the radiation spectrum is mixed: against the background of a continuous continuum, individual spectral lines that are characteristic of a particular gas are distinguished. The power of such arc lamps reaches several kilowatts. To ensure the operating mode, they are connected to a power supply unit, which includes an ignition device and a current source.

The bulb of the discharge lamp may also be filled with an inert gas, preferably xenon, at a pressure lower or close to atmospheric. These are flash discharge lamps connected to a power supply unit containing an ignition device, a capacitive storage device and a charger. The pulse power of such lamps reaches hundreds of kilowatts, the emission spectrum in the ultraviolet region is continuous, starting from the short-wavelength transmission limit of a quartz bulb (185 nm) to the beginning of the visible range (380-400 nm).

Sources of ultraviolet radiation 6 can be equipped with reflectors of various designs (not shown).

In an embodiment, in the device for disinfecting bulk products, the means for transporting the product can be made in the form of a hollow drum 8, mounted for rotation around its axis due to the bearings 9. The rotation of the drum 8 is driven by an electric motor 10, a small gear 11 on the motor shaft and located in meshing with her big gear 12, mounted on the drum 8.

The ultraviolet radiation source 6 is installed in the cavity of the drum 8 along its axis (coaxially or in parallel) so that the lamp electrodes are located outside the drum and are connected to the power supply 13.

The axis of rotation of the drum 8 is inclined to the horizon at an angle α, which can take a value from 0 to 20-30 degrees. The inner surface of the drum 8 can be performed with a screw thread or ribbed.

In another embodiment, in the device for disinfecting bulk products, the means for transporting the product can be made in the form of a sprinkler device with distributors of falling loose product, providing free fall and rolling of particles of the product (for example, grain) in the irradiation field.

The sequence of operations that make up the essence of the proposed method for the disinfection of bulk products, and the operation of the proposed device for implementing the proposed method will be clear from the following description of work.

The initial bulk product is placed in the loading unit 1 and dosed into the tray 2. Due to the operation of the vibrator 5, the tray 2 experiences oscillatory movements, the direction, frequency and intensity of which are determined by the characteristics of the vibrator and the direction of its oscillation axis. In figure 1, the arrows on the vibrator 2 indicate the direction of the axis of oscillation. With this setting of the vibrator, tray 2 oscillates both along the horizon and vertically, and the ratio of the amplitudes of these components is entirely determined by the angle of inclination of the vibrator axis 5.

As a result of such an oscillatory movement of the tray 2, individual particles of the granular product located on it move along the surface of the tray towards the discharge device 7 (due to the horizontal component of the oscillatory movement of the tray) and simultaneously are thrown up (due to the vertical component of the oscillatory movement of the tray), fall and roll over, those. during the movement, they change their orientation relative to the source of ultraviolet radiation 6. This behavior of individual particles of the bulk product resembles the boiling of a liquid and can be interpreted as “pseudo-boiling” or “fluidization” of dry bulk products.

The particles of the bulk product located in the "fluidized bed" are irradiated with ultraviolet radiation 6. The processed bulk product is accumulated in the discharge device 7.

The entire process of processing and transportation of the product occurs continuously due to the coordination of the vibrator settings and the performance of the loading device.

A feature of the embodiment of the proposed device with a rotary means for transporting the processed product (figure 3) is that due to the rotation of the drum 8 using the drive 10, 11, 12 and the inclination of its axis simultaneously with the movement of the product particles to the discharge device 7 is ensured and rolling particles, i.e. during processing, the orientation of the particles of the product relative to the source of ultraviolet radiation 6 changes, as a result of which they are irradiated from different sides. Depending on the properties of the initial bulk product (particle size, fractionality, adhesion, degree of microbiological contamination, etc.), the value of the angle of inclination of the drum axis α and the angular velocity of rotation of the drum are selected so as to ensure that each individual particle of the processed product in the irradiation zone a source of ultraviolet radiation 6 for the time necessary to achieve a given degree of disinfection of the product.

In an embodiment of the inner surface of the drum 8 with a threaded thread, the angle α can be equal to 0, since the necessary longitudinal movement of the product is ensured by the parameters of the spiral helical threading in the same way as in screw conveyors.

It is well known that ultraviolet radiation has a pronounced biocidal effect and effectively inactivates microorganisms of various types - bacteria, spores, viruses, micro-fungi, etc. In contrast to ionizing radiation, which has great penetrating power (tens of centimeters or more), ultraviolet radiation is very strongly absorbed almost all solids - the characteristic ranges of photons in solid condensed matter range from fractions of a micron to several microns. Therefore, under ultraviolet irradiation of a solid particle, only its finest surface layer is subjected to processing, while the bulk of the substance is not exposed to any effect and, accordingly, does not change its biochemical properties. This is an advantage of the proposed method for the disinfection of bulk products in comparison with known methods.

In the proposed method and device, the disinfecting effect on the processed product ceases at the moment when the product leaves the irradiation zone and enters the discharge device, i.e. there is no aftereffect. For the same reason, there is no risk of overdose.

The proposed method and device have the property of universality with respect to the type and characteristics of a particular processed bulk material. This advantage of the proposed solution is due to the fact that disinfection using ultraviolet radiation occurs on the surface of the particles of bulk material, regardless of the composition and structure of the inner part of the particles, the effectiveness of disinfection is determined by the dose of ultraviolet radiation and the mixing efficiency of the processed bulk material during irradiation. The mixing efficiency, in turn, depends on the adjustments of the applied means for transporting the processed product, configured to change the orientation of the individual particles of the granular product relative to the source of ultraviolet radiation. These adjustments for various bulk materials, for example for fine-grained products (powders or products in the form of flour) and for coarse-grained (in the form of grains, small fruits, etc.), will be different.

The experimental installation for the disinfection of bulk products is assembled on the basis of a vibrating conveyor, which provided the processed products in a state of fluidization (boiling) and moving them at a variable speed. Bulk products were irradiated with a tubular pulsed xenon lamp type INP-11/250 with dimensions of the luminous body d × L = 11 × 250 mm. The electric discharge energy in the lamp was 600 J with a radiation pulse duration in the UV spectral region of ~ 100 μs. The lamp worked with a pulse repetition rate of 1 Hz and an average electric power of 600 W; The peak electric power of the lamp was 6 MW. In the UV region of the spectrum with wavelengths shorter than 310 nm, the lamp emits ~ 10% of the discharge energy when the radiation flux integrated over the spectrum from the lamp surface is ~ 30 kW / cm ² . Irradiation of objects was carried out from a distance of 15 ... 20 cm from the lamp, while lighting systems concentrating the radiation flux (reflectors, etc.) were not used. Microbiological analysis of test objects before and after irradiation was carried out at the Central Laboratory of Microbiology of the All-Russian Research Institute of the Dairy Industry.

An experimental study of the possibilities of the proposed method for the disinfection of bulk food products was carried out using black pepper - peas and ground fractions and protosubtylene enzyme flour as test objects. The latter is used as a protein supplement to animal feed. The peculiarity of protosubtylene as an object of disinfection lies in its fundamental thermal stability: when heated above ~ 50 ° C, its useful properties (enzyme activity) decrease significantly.

The results of the studies are presented in table 1.

Table 1 No pp Product name, exposure time BGKP KMAFANM, CFU / g The effectiveness of disinfection,% one Black pepper peas 1.1 Source Found in 0.01 g 7 · 10 ⁶ 1.2 Processing 0.5 min Found in 0.01 g 2.7 · 10 ⁶ 61.43 1.3 6 min processing None in 0.1 g 2.5 · 10 ³ 99.96 2 Ground black pepper 2.1 Source Found in 0.001 g 4 · 10 ⁶ 2.2 Processing 0.5 min Found in 0.001 g 2.7 · 10 ⁶ 32,50 2.3 6 min processing None in 0.1 g 1.410 ⁶ 65.00 3 Protosubtilen 3.1 Source None in 0.1 g 2 · 10 ⁹ 3.2 1 min processing None in 0.1 g 4 · 10 ⁷ 98.00 3.3 3 min processing None in 0.1 g 5 · 10 ⁶ 99.75 3.4 6 min processing None in 0.1 g 2 · 10 ⁵ 99,99 Notes: BGKP - bacteria of the group of Escherichia coli;
KMAFAnM - the number of mesophilic, aerobic, facultative anaerobic microorganisms;
CFU / g - the number of colony forming bacteria in 1 g of the product.

As can be seen from the presented data, with the appropriate choice of processing time, the proposed method and device allows for deep disinfection of bulk products: after six minutes of irradiation of a large fraction of black pepper and finely divided (~ 50 μm) enzyme flour, the total microbiological contamination decreased by 3 ... 4 order (disinfection efficiency of 99.9 ... 99.99%), while the heating of the enzyme meal did not exceed 35 ° C. For black pepper, E. coli bacteria were not found in 1 mg of the processed product, regardless of its fractional composition (San PiN standard 2.3.2.1078-01 - the absence of 10 mg of the product). At the same time, a significant (more than an order of magnitude) decrease in the total contamination of yeast and molds was observed in all the test objects studied.

Control studies of protosubtylene after such treatment showed the preservation of its enzymatic activity.

Thus, the proposed method and device provide deep disinfection of a wide range of bulk products while maintaining their consumer qualities in the absence of aftereffect and extremely low risk of overdose.

Claims (3)

1. A method of processing bulk products by irradiation, comprising exposing the processed product to ultraviolet radiation during its movement with a change in the orientation of its individual particles relative to the radiation source, characterized in that the processed product is irradiated with pulsed ultraviolet radiation of a continuous spectrum in the wavelength range from 185 to 400 nm using a pulsed discharge lamp with a pulse duration of radiation from 1 μs to 10 ms and the density of the pulsed radiation power at the processing Vai product not less than 100 kW / m ^2. 2. A device for processing bulk products by irradiation, comprising a loading unit, a source of ultraviolet radiation, means for transporting the processed product, configured to change the orientation of the individual particles of the bulk product relative to the source of ultraviolet radiation, and an unloading unit, characterized in that the source of ultraviolet radiation is made in in the form of a pulsed discharge lamp connected to a power supply with a capacitive storage device, a charger and an ignition unit. 3. The device according to claim 2, characterized in that the means for transporting the processed product is made in the form of a vibration conveyor, which is a tray mounted on shock absorbers, with a scarf attached to the bottom of the tray on which a vibrator with an adjustable direction of vibrational vibrations is mounted, or in the form of a hollow drum mounted with the possibility of rotation around its axis, and the axis of rotation of the drum is inclined to the horizon at an angle of not more than 30 °, and the source of ultraviolet radiation has established n coaxially or parallel to the drum axis, wherein the source of radiation electrodes are arranged outside the drum and connected to the power supply.

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