RU2352880C2 - Infrared dryer - Google Patents

Abstract

FIELD: heating, drying.

SUBSTANCE: invention relates to devices for drying high-moisture materials, such as vegetables, fruits, berries, garden and wild greens, fungi, meat etc. Infrared dryer consists of a body with six rectangular holes, in which are embedded screen trays, drying chambers, separated by intermediate pans for collecting spillage in three sections, covers, IR-emitters, ventilators, control unit for regulating the drying process, temperature set-point device and three sensors in the drying chamber. IR-emitters work in a pulse regime. The ventilator supplies the outside air to the section of the drying chamber through grooves on the side wall and the perforated holes of the front wall and together with the evaporated moisture leaves through slits in the back wall.

EFFECT: increase the amount of workable material three times without increasing one-time load on the electric current network, and excluding the loss of energy due to spillage of dusty materials on the outer surface of the emitters.

2 dwg

Description

The dryer is designed for dehydration (drying) of moisture-containing materials, such as vegetables, root vegetables, fruits, berries, herbs, mushrooms, meat, etc. The crushed material is laid out on six mesh pallets, which are inserted into the drying chamber. In the drying chamber, divided into three equal sections by two intermediate and one lower spill collection pallets, three temperature sensors (one in each section) are installed between the mesh pallets (two in each section) connected to the automatic control unit of the drying process, in which there is a limiter for the temperature and drying time, six infrared (IR) emitters, each installed in the profile of the side walls, and the inner surface of the walls and the pallets intermediate and lower are made of material, and eyuschego high reflectivity.

The technical result of the invention are: the ability to turn on only two IR emitters of one section - sequentially section by section, to create a uniform field of IR radiation simultaneously on two mesh pallets with material to protect the surface of the IR emitters from dusty spills that absorb radiation energy, and automatic process control drying.

The invention relates to a device for drying highly moist materials, such as vegetables, fruits, berries, garden and wild herbs, mushrooms, meat, etc.

A device is known according to the author's certificate of the USSR No. 1513352, IPC Е26В 3/30, 1986. The device includes a drying cabinet with a tray inserted for drying material, on both sides of which are IR emitters and fans.

IR emitters carry out intensive drying of the material in the first stage and drying with a reduced by 50% radiation intensity in the second stage with a change in the intensity of exposure to the sides, after which the material is dried.

The disadvantages of the known device are: the sedimentation of small particles of material waking up from the pallet, and moisture drops on the surface of infrared emitters, which leads to a deterioration in the intensity of irradiation over time, the irregularity of the field of infrared irradiation on the surface of the material, at the shortest distance perpendicular from the infrared emitter to the pallet, it is higher than at the edges of the pallet, the radiation intensity is reduced by 50% per stage by time, but for different materials the duration of the stages is different and depends on the initial humidity, uneven blowing of the pallet fans leads to different drying speeds of the material. In addition, this leads to an increase in the duration of the process.

Known radiation dryer for plant food products according to the patent RU 2034489 C1, 6 A23B 7/02, F26B 3/30, 05/10/95, Bull. No. 13, having a housing inside which trays for the dried raw material are placed, radiation IR emitters of the middle spectral region, reflectors of various designs, slots for air passage from the bottom up of the dryer.

The disadvantages of the known dryers are: the location of the infrared emitters under and above the trays, which, taking into account a certain distance between the infrared emitters themselves and the infrared emitters and trays, does not provide a uniform distribution of radiation energy over the area of the tray. The energy of infrared radiation in the middle region of the spectrum is absorbed mainly by the surface of the dried material and, in order to prevent its cracking and deformation, which worsen the quality of the finished product, it is necessary to reduce the amount of energy supplied, which reduces the drying intensity and affects the economic and time parameters of the process. Deteriorating these same indicators and the continuous supply of infrared energy. In addition, the continuous supply of infrared energy creates in the surface and near-surface layers of the material to be dried, especially opposite the IR emitters, a temperature gradient directed inside the sliced product. This prevents heat and mass transfer, that is, worsens the conditions for the movement of moisture from the inner layers to the outer. An important disadvantage is that all IR emitters turn on simultaneously. This entails high power consumption and increases the load on the electric current network.

Closest to the proposed infrared dryer is an infrared dryer according to the patent RU 2265169 C2, 11/27/2005, Bull. No. 33 for dewatering high-moisture materials, which has a drying chamber in the housing, into which two mesh pallets with dried material, two IR emitters, a fan and an automatic control unit are inserted.

A disadvantage of the known dryer is the ratio of the work and pause of the IR emitter as 1: 3. For this reason, 2/3 of the operating time of the dryer is lost for a pause, which reduces the amount of simultaneously dried material. It is possible to increase the amount of simultaneously dried material by three times only with three dryers, but this will increase the simultaneous load on the electric current network by three times. In this case, the ratio of the work and the pause of the IR emitter as 1: 3 is not eliminated.

The purpose of the invention is to increase the amount of simultaneously dried material without increasing the power simultaneously supplied to the IR emitters with the stability of the energy characteristics of infrared radiation, to prevent dust particles of the material and moisture droplets from entering the surface of the IR emitters, to create uniform irradiation on the surface of the material, to ensure continuous blowing material on all pallets; automatic regulation of the drying process of various materials.

The goal is achieved by the fact that in the infrared dryer for dehydration of high-moisture materials, including a housing with a drying chamber, into which six mesh pallets with the material to be dried, six infrared emitters, two intermediate pallets and one lower one, a fan and an automatic control unit are inserted, and in the back the inlet wall has air inlets and outlet openings and a lower slot for removing it together with evaporated moisture, according to the invention, the drying chamber is divided between full-time pallets in three sections, containing two mesh pallets at the top and bottom of the section, between which a temperature sensor is installed, connected to an automatic control unit with a set point for setting the maximum heating temperature, two IR emitters installed each in the side wall profile at equal distances from mesh pallets, while the infrared emitters are switched on sequentially in sections of the drying chamber, observing a cycle duration of 1: 3.

Figure 1 presents a cross section of a dryer along aa in figure 2; figure 2 is a longitudinal section of a dryer.

The infrared dryer for dewatering high-moisture materials consists of a housing 1 with six rectangular openings 2, forming a drying chamber of the side walls 3, 4 with a special profile 5, front walls 6 and pallets for collecting spills 7, dividing the drying chamber into three sections, covers 8, mesh pallets 9, IR emitters 10 installed in the profile 5, back wall 11, fans 12, control unit for automatic control of the drying process 13. On the front walls 6 at an equal distance from the side walls 3, 4 and two mesh pallets 9 in each section, temperature sensors 14 are connected to the unit 13, to which is also connected a dial 15 for setting the maximum heating temperature, which limits the temperature in the drying chamber at which the IR emitters operate in a pulsed mode.

For air supply in the housing 1, opposite the fans 12, round entrance holes 16 are made, three grooves 17 are made for air passage in the side wall 4, perforations of the holes 18 are made in the front walls 6, for the air outlet in the rear wall 11, opposite five mesh pallets made outlet openings 19, and the lower edge of the rear wall 11 with the lower pan collecting spill 7 form a lower slot 20 opposite the lower mesh pan to remove air along with evaporated moisture.

The dryer operates as follows. The mesh pallets 9 are loaded with crushed dried material and inserted into the drying chamber through rectangular openings 2 in the housing 1 along the guides of the side walls 3, 4. The temperature limiter 15 is set for the given type of material to be dried. The infrared emitters 10 in the upper section of the drying chamber and the fans 12 are turned on. The material located on the mesh pallets is irradiated with direct and reflected rays from the side wall profile until the temperature in the section reaches the limit set. For each type of material, this temperature is determined experimentally.

After reaching the maximum set drying temperature, the infrared emitters are switched off by a sensor signal and transferred to the pulse switching mode. The duration of the pulsed switching on and pauses are correlated as 1: 3 and depend on the type of material and the limit temperature set in the dryer by the setter. The ratio of 1: 3 allows you to turn on two IR emitters in the upper section at the beginning, and not to turn on two in the middle section and two in the lower section, then turn on two middle IR emitters at the command of the middle section sensor, simultaneously turn off the two upper ones, then turn on the sensor command of the lower section two lower infrared emitters, at the same time turn off two middle. Then, at the command of the upper sensor, the two upper infrared emitters are turned on again, and the two middle and two lower infrared emitters are turned off. This cycle is repeated until the drying process. In this case, the fan is constantly on. Evaporated moisture in a mixture with air blown through the crushed material is removed outward through the grooves 19 in the rear wall and the slit 20.

At the end of the drying process, the automatic control unit turns off the IR emitters and the fan and the infrared dryer is loaded with a new batch of material.

The proposed dryer allows, without increasing the power simultaneously supplied to the IR emitters, to triple the amount of processed material by filling the pause time with IR radiation, not to increase the one-time load on the electric current network, by eliminating the need for IR emitters in the side wall profiles energy losses due to the ingress of dusty spills of material and moisture drops on the outer surface of the emitters, reduce the energy intensity of the process by using the energy of the reflected rays minutes, transferred onto mesh trays, to improve product quality by irradiation uniformity of distribution formed by the profiles of the side walls, to reduce power consumption by automatically maintaining pulse pause ratio for each type of product.

Claims (1)

Infrared dryer for dehydration of high-moisture materials, including a housing with a drying chamber, into which six mesh pallets with a dried material, six IR emitters, two intermediate pallets and one lower one, a fan and an automatic control unit are inserted, and inlets are provided in the rear wall for air supply and outlet upper openings and a lower slot for removing it together with evaporated moisture, characterized in that the drying chamber is divided by intermediate pallets for three seconds II, containing two mesh pallets at the top and bottom of the section, between which a temperature sensor is installed, connected to an automatic control unit having a set point for setting the maximum heating temperature, two IR emitters installed each in the side wall profile at equal distances from the mesh pallets, in this case, the IR emitters are switched on sequentially in sections of the drying chamber, observing a duty cycle of 1: 3.

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