CN110553475A

CN110553475A - Drying box and heat flow circulation control method

Info

Publication number: CN110553475A
Application number: CN201910818714.6A
Authority: CN
Inventors: 喻季红; 龚伟业; 谢品德; 张仲焘
Original assignee: Hunan Sundy Science and Technology Development Co Ltd
Current assignee: Hunan Sundy Science and Technology Development Co Ltd
Priority date: 2019-08-30
Filing date: 2019-08-30
Publication date: 2019-12-10
Anticipated expiration: 2039-08-30
Also published as: CN110553475B

Abstract

The invention discloses a drying oven and a heat flow circulation control method, which belong to the technical field of sample total moisture measurement and are used for solving the technical problem of low drying efficiency of the existing drying oven, and the adopted technical scheme is as follows: the heating device comprises a box body, a main cavity and two sides of a heating cavity main cavity, wherein the main cavity and the two sides of the heating cavity main cavity are respectively provided with an air return channel; the heating cavity is provided with an exhaust port at the air inlet of each air return channel, and the exhaust port is provided with a telescopic folding door which is switched between a folding state and a stretching state; when the telescopic folding door is in a folding state, the exhaust port is blocked by the telescopic folding door in the folding state, and the air inlet of each air return channel is opened to carry out an internal circulation mode; when the telescopic folding doors are in the stretching state, the air inlets of the air return channels are blocked by the telescopic folding doors in the stretching state, and the air outlets are opened to carry out an external circulation mode. The technical scheme has the advantages of high drying efficiency, strong applicability and the like.

Description

Drying box and heat flow circulation control method

Technical Field

The invention mainly relates to the technical field of sample total moisture measurement, in particular to a drying box and a heat flow circulation control method.

Background

For the determination of the total moisture of the coal sample, the drying of the sample and the verification of the weight of the sample are the two most important links, particularly, the advantages and disadvantages of a drying oven directly influence the drying efficiency and the compliance of the drying environment, particularly, the latest standard requirements put forward higher requirements for the drying oven, and further put forward the requirement of forced nitrogen introduction for the lignite standard.

The traditional drying box adopts a light wave heating mode or a light wave and blast heating combined mode, the drying mode requirement of national standard for measuring total water of a coal sample is not met, meanwhile, the traditional drying box is large in size, under the condition that the latest pragmatic standard enforces nitrogen introduction drying on lignite, the nitrogen consumption is large, meanwhile, the requirement that the nitrogen concentration in the drying box reaches 99.9% is difficult to ensure, meanwhile, the large drying box is difficult to ensure that the temperature in a cavity is within a qualified value range, and moreover, the traditional drying box is difficult to discharge water vapor flow rapidly due to insufficient gas exchange speed, so that the drying efficiency is low.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at the technical problems in the prior art, the invention provides a drying box with high drying efficiency and a heat flow circulation control method.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a drying box comprises a box body and a main cavity formed by enclosing the box body, wherein one end of the box body is provided with a sample inlet door, the opposite end of the sample inlet door is provided with a heating cavity communicated with the main cavity, a blowing heating assembly is arranged in the heating cavity, both sides of the main cavity are provided with return air channels, air inlets of the return air channels are communicated with the heating cavity, air outlets of the return air channels are positioned at both sides close to the sample inlet door and are communicated with the main cavity, and the main cavity, the heating cavity and the two return air channels are sequentially communicated to form an internal circulation air channel; an air inlet assembly facing the heating cavity is arranged on one side of the sample injection door of the main cavity; the heating cavity is provided with an air outlet at an air inlet of each air return channel, and a telescopic folding door which is switched between a folding state and a stretching state is arranged at the air outlet; when the telescopic folding door is in the folded state, the air outlet is blocked by the telescopic folding door in the folded state, and the air inlet of each air return channel is opened to carry out an internal circulation mode; when the telescopic folding doors are located in the stretching state, the air inlets of the air return channels are blocked by the telescopic folding doors in the stretching state, and the air outlets are opened to carry out an external circulation mode.

As a further improvement of the above technical solution:

The telescopic folding door comprises a plurality of door bodies which are sequentially hinged, wherein the door body on one side is hinged to the inner wall of the box body, the door body on the other side is connected with a driving piece, and the driving piece is in linear motion to drive the door bodies to be switched between a folding state and a stretching state.

The driving piece comprises a rotating motor and a screw rod mechanism, and the rotating motor is connected with the door body through the screw rod mechanism.

The gas inlet assembly comprises a nitrogen gas inlet unit, an air gas inlet unit and a strip gas distributor, and the gas distributor is arranged along the arrangement direction of the sample inlet door; the nitrogen gas inlet unit and the air gas inlet unit are respectively connected with the gas distributor and are interlocked.

The nitrogen gas inlet unit comprises a nitrogen gas source, a pressure reducing valve, a nitrogen gas electric control switch and a drying module which are sequentially connected, and the drying module is connected with one end of the gas distributor; the air inlet unit comprises an air electric control switch, and the air electric control switch is connected with the other end of the air distributor; the nitrogen electric control switch and the air electric control switch are electrically or mechanically interlocked.

The sampling door comprises a door plate, a rotating rod and a driving assembly, one end of the door plate is rotatably installed on the box body through a rotating shaft, one end of the rotating rod is connected with the door plate, the other end of the rotating rod is connected with the driving assembly, the driving assembly is used for driving the rotating rod to rotate and realize opening and closing of the door plate, and certain self-closing force is provided when the door plate is closed.

the sampling door comprises a door plate, wherein the upper end of the door plate is arranged on the box body through a hinge piece, so that the door plate is turned over and opened in the box body under the pushing of external force or falls back and is closed under the action of gravity.

The lower end edge of the door panel is in a circular arc transition shape.

The air blowing heating assembly comprises an air blowing assembly and a heating assembly; the air blowing assembly comprises a centrifugal fan and a centrifugal fan blade; the centrifugal fan is arranged on the outer side of the box body, and the blades of the centrifugal fan are arranged in the heating cavity and are connected with the centrifugal fan; the main chamber is provided with an air inlet of the heating cavity at the inner circle of the centrifugal fan blade.

The heating assembly is positioned on one side or two sides of the heating cavity on the air blowing assembly and used for heating the air.

The heating component is a PTC heating sheet.

the shape of PTC heating plate with heating chamber phase-match, just the heating chamber is provided with the deep bead in the line terminal department of PTC heating plate.

the air blowing assembly and the heating assembly are both positioned on the mounting plate on one side of the box body.

and a heat insulation plate is laid on the inner side of the mounting plate.

A temperature detection piece is arranged in the box body and used for detecting the temperature of the gas in the main cavity; the heating assembly is connected with the temperature detection piece and used for receiving the detected gas temperature value and heating and adjusting the gas temperature value so as to maintain the gas temperature in the main cavity within a constant range.

The temperature detection piece comprises a fixed seat and a temperature measurement probe, the fixed seat is detachably connected to the side wall of the return air channel, and the temperature measurement probe is installed in the fixed seat.

Each the gas outlet of return air passageway includes a plurality of vertical bar holes, and the length in each bar hole shortens in proper order along gas conveying direction.

And a mixed flow plate is arranged at the air outlet of each air return channel.

And a heat insulation layer is laid on the outer layer of the box body.

A section of the main chamber adjacent the heating chamber gradually contracts towards the heating chamber.

The main cavity is internally provided with a concentration detection piece for detecting the concentration of water vapor so as to control the telescopic folding door to be switched between a folding state and a stretching state.

The invention also discloses a heat flow circulation control method based on the drying box, which comprises the following steps:

S01, detecting the water vapor concentration of the main chamber in the box body;

S02, when the detected water vapor concentration does not reach the preset water vapor concentration, controlling the telescopic folding door to be switched to a folding state, plugging the exhaust port, and opening the air inlet of each return air channel to dry the sample in an internal circulation mode; when the detected water vapor concentration reaches the preset water vapor concentration, the telescopic folding door is controlled to be switched to a stretching state, the air inlets of the air return channels are blocked, and the air outlets are opened to enter an external circulation mode to discharge water vapor.

As a further improvement of the above technical solution:

In step S01, the water vapor concentration of the main chamber in the box body is obtained by the water vapor concentration detection member or the opening time according to the internal circulation pattern in the box body.

in step S02, after the external circulation mode is entered, the mode is switched to the internal circulation mode after a predetermined time has elapsed.

Compared with the prior art, the invention has the advantages that:

According to the drying box, the air internal circulation speed in the circulating air duct can be increased through the air blowing effect of the air blowing heating assembly, the circulation period is short, and therefore the drying effect is improved; furthermore, the air is circularly heated by matching with the blast heating assembly, so that the rising of the gas temperature is accelerated, the temperature rising time is reduced, the evaporation of water inside and outside the sample is accelerated to form vapor, the consumption of nitrogen in the main cavity is greatly reduced, and meanwhile, the power of the cavity heating sheet can be greatly reduced by an internal circulation mode, and the purpose of saving energy can be achieved; when the concentration of the water vapor in the main cavity reaches or approaches to the saturated vapor pressure, the telescopic folding door is switched between a folding state and a stretching state, so that the switching from an internal circulation mode to an external circulation mode is realized, the discharge of the water vapor is accelerated through the exhaust port, and the drying efficiency of subsequent samples is further improved; in addition, the telescopic folding door has simple and ingenious structure and is simple, quick, convenient and effective to switch.

According to the drying box disclosed by the invention, the temperature detection piece is arranged in the box body and used for detecting the gas temperature in the main cavity so as to heat and regulate the heating assembly, so that the gas temperature in the main cavity is maintained in a constant range.

according to the drying box, the air outlet of each air return channel comprises a plurality of vertical strip-shaped holes, and the length of each strip-shaped hole is sequentially shortened along the air conveying direction, so that the whole air outlet is in a V shape, hot air in the air return channels can be uniformly mixed, and the temperature difference of the air outlet is reduced; furthermore, a mixed flow plate is arranged at the air outlet of each air return channel to uniformly mix hot air again, so that the temperature difference of air at each position is further reduced, and the temperature in the whole main cavity is ensured within a reasonable range.

According to the drying box disclosed by the invention, the shape of the box body is compatible with the drying operation in the total moisture measurement of the coal samples of 6mm and 13mm, and the drying box can be flexibly configured according to the requirements of customers. In addition, the whole platykurtic that is of box, and one section that the main cavity is close to the heating chamber is to heating chamber shrink gradually, the gaseous circulation in the main cavity chamber of not only being convenient for, shape and the inner space that can guarantee the box simultaneously are minimum, reduce the consumption of nitrogen gas under the condition of guaranteeing drying efficiency, have practiced thrift the required consumptive material cost of drying operation.

According to the heat flow circulation control method, the evaporation of water inside and outside the sample is accelerated through internal circulation to form vapor, so that the consumption of nitrogen in the main cavity is greatly reduced, and meanwhile, the power of the cavity heating sheet can be reduced to a great extent by means of the internal circulation, and the purpose of energy conservation can be achieved; when the concentration of the water vapor in the main cavity reaches or approaches to the saturated vapor pressure, the folding state is switched to the stretching state from the folding state through the telescopic folding door, so that the switching from the internal circulation mode to the external circulation mode is realized, the discharge of the water vapor is accelerated through the exhaust port, and the drying efficiency of subsequent samples is further improved; through the matching of the internal and external circulation modes, the sample is quickly dried.

Drawings

Fig. 1 is a view showing an internal structure of a casing in the embodiment of the present invention.

FIG. 2 is a diagram of an internal circulation pattern in an embodiment of the present invention.

Fig. 3 is a diagram of an external circulation pattern in an embodiment of the present invention.

Fig. 4 is a structural view (in a stretched state) of the retractable folding door in the embodiment of the present invention.

Fig. 5 is a structural view (in a folded state) of the telescopic folding door in the embodiment of the present invention.

Fig. 6 is a structural view of an intake assembly in an embodiment of the present invention.

FIG. 7 is a structural diagram of a sample injection door in an embodiment of the present invention.

Fig. 8 is a structural view of a blower heating assembly in an embodiment of the present invention.

Fig. 9 is a structural view of the air outlet of the return air duct in the embodiment of the invention.

Fig. 10 is a structural view of a temperature detection member in the embodiment of the present invention.

The reference numbers in the figures denote: 1. a blower heating assembly; 101. a centrifugal fan; 102. a centrifugal fan blade; 103. a heat insulation plate; 104. mounting a plate; 105. a wind deflector; 106. a heating assembly; 2. an internal circulation air duct; 201. a heating cavity; 202. an air return channel; 203. a strip-shaped hole; 204. a flow mixing plate; 205. a main chamber; 3. a sample introduction door; 301. a door panel; 302. sealing cotton; 303. a drive assembly; 304. rotating the rod; 4. a temperature detection member; 401. a temperature measuring probe; 402. a fixed seat; 5. an air intake assembly; 501. a gas distributor; 502. a nitrogen gas inlet unit; 5021. a nitrogen source; 5022. a pressure reducing valve; 5023. a nitrogen electric control switch; 5024. a drying module; 503. an air intake unit; 5031. an air electric control switch; 6. a box body; 601. a heat insulation layer; 7. an exhaust port; 8. a retractable folding door; 801. a door body; 802. a drive member.

Detailed Description

The invention is further described below with reference to the figures and the specific embodiments of the description.

As shown in fig. 1 to 10, the drying oven of the present embodiment is used for drying operation in sample moisture determination, and includes an oven body 6 and a main chamber 205 enclosed by the oven body 6, wherein one end of the oven body 6 is provided with a sample introduction door 3, one end of the sample introduction door 3 opposite to the main chamber 205 is provided with a heating chamber 201 communicated with the main chamber 205, a blowing heating assembly 1 is arranged in the heating chamber 201, two sides of the main chamber 205 are provided with return air channels 202, air inlets of the return air channels 202 are communicated with the heating chamber 201, air outlets of the return air channels 202 are located at two sides close to the sample introduction door 3 and are communicated with the main chamber 205, and the main chamber 205, the heating chamber 201 and the two return air channels 202 are sequentially communicated to form an internal; the main chamber 205 is provided with an air intake assembly 5 facing the heating chamber 201 at one side of the sample inlet door 3; the heating cavity 201 is provided with an exhaust port 7 at the air inlet of each air return channel 202, and a telescopic folding door 8 which is switched between a folding state and a stretching state is arranged at the exhaust port 7; when the retractable folding door 8 is in a folded state, the exhaust port 7 is blocked by the retractable folding door 8 in the folded state, and the air inlet of each air return channel 202 is opened to perform an internal circulation mode; when the retractable folding doors 8 are in the stretched state, the air inlet of each return air duct 202 is closed by the retractable folding doors 8 in the stretched state and the air outlet 7 is opened to perform the external circulation mode.

According to the drying box, the air internal circulation speed in the circulating air duct can be increased through the air blowing effect of the air blowing heating assembly 1, the circulation period is short, and therefore the drying effect is improved; furthermore, the air is circularly heated by matching with the blast heating assembly 1, so that the temperature rise of the air is accelerated, the temperature rise time is reduced, the evaporation of water inside and outside the sample is accelerated to form vapor, the consumption of nitrogen in the main chamber 205 is greatly reduced, and meanwhile, the heating power can be greatly reduced by an internal circulation mode, and the purpose of saving energy can be achieved; when the concentration of the water vapor in the main chamber 205 reaches or approaches to the saturated vapor pressure, the telescopic folding door 8 is switched between the folding state and the stretching state, so that the switching from the internal circulation mode to the external circulation mode is realized, the discharge of the water vapor is accelerated through the exhaust port 7, and the drying efficiency of subsequent samples is further improved; in addition, the structure of the telescopic folding door 8 is simple and ingenious, and the switching is simple, quick, convenient and effective.

As shown in fig. 4 and 5, in the present embodiment, the retractable folding door 8 includes a plurality of door bodies 801 hinged in sequence, wherein the door body 801 on one side is hinged on the inner wall of the box 6, the door body 801 on the other side is connected with a driving member 802, and the driving member 802 performs a linear motion to drive the door body 801 to switch between the folding state and the stretching state. The driving member 802 includes a rotating motor and a screw mechanism, the rotating motor is connected to the door 801 through the screw mechanism, and the rotating motion of the rotating motor is converted into a linear motion through the screw mechanism, so as to drive the door 801 to switch between a folded state and a stretched state. As shown in fig. 5, when the retractable folding door 8 is in the folded state, the air outlet 7 is blocked by the retractable folding in the folded state, and at this time, the air inlet of each air return channel 202 is opened to perform the internal circulation mode, as shown in fig. 2; when the retractable folding doors 8 are in the extended state, as shown in fig. 4, the intake ports of the respective return air ducts 202 are closed by the retractable folding doors 8 in the extended state, and the exhaust ports 7 are opened at this time to perform the external circulation mode, as shown in fig. 3. Of course, in other embodiments, the screw mechanism may also adopt other conversion mechanisms such as a rack and pinion mechanism, or directly adopt a telescopic cylinder or a telescopic oil cylinder to realize the state switching of the door body 801.

As shown in fig. 6, in the present embodiment, the gas inlet assembly 5 includes a nitrogen gas inlet unit 502, an air inlet unit 503, and a strip gas distributor 501, and the gas distributor 501 is disposed along the arrangement direction of the injection door 3; the nitrogen gas inlet unit 502 and the air gas inlet unit 503 are respectively connected with the gas distributor 501, and the nitrogen gas inlet unit 502 and the air gas inlet unit 503 are interlocked; specifically, the nitrogen gas inlet unit 502 includes a nitrogen gas source 5021, a pressure reducing valve 5022, a nitrogen gas electric control switch 5023 and a drying module 5024 (such as a drying agent) which are connected in sequence, and the drying module 5024 is connected with one end of the gas distributor 501; the air inlet unit 503 comprises an air electronic control switch 5031, and the air electronic control switch 5031 is connected with the other end of the air distributor 501; nitrogen electrical switch 5023 is electrically or mechanically interlocked with air electrical switch 5031. In actual work, different air inlet units can be switched according to the properties of the coal sample, for example, anthracite and dry bituminous coal with ash-free base volatile components less than 20% are subjected to air drying, and anthracite, bituminous coal and lignite are subjected to nitrogen drying, and the rationality of a sample drying mode is ensured through the switching (for example, selection is carried out on an operation interface) of the air inlet units according to the properties of the coal sample, so that the applicability of the drying box is improved. In addition, the gas distributor 501 is arranged along the arrangement direction of the sample inlet door 3, the gas distributor 501 is a long gas pipe, a plurality of gas outlets (circular or long-strip-shaped and the like) are arranged on the long gas pipe, and the gas distributor enters from two end parts of the long gas pipe, so that parallel nitrogen flows are formed, the nitrogen pressure and the nitrogen flow at each gas outlet are consistent, the distance between the gas outlets is gradually shortened along the direction from the gas inlet end to the middle, and the sizes of the gas outlets are also gradually increased; meanwhile, the gas distributor 501 is arranged at the hot air flow reversing position of the main chamber 205, so that the hot air flows at two ends can quickly heat the nitrogen, and the two hot air flow reversing positions form a relatively low-pressure area, so that the nitrogen can flow in an accelerated manner, and the nitrogen concentration in the main chamber 205 can reach the required standard concentration more quickly.

As shown in fig. 7, in this embodiment, the sample inlet door 3 includes a door panel 301, a rotating rod 304 and a driving component 303, a high temperature sealing cotton 302 is embedded in the door panel 301, one end of the door panel 301 is rotatably installed on the box body 6 through a rotating shaft, one end of the rotating rod 304 is hinged to the door panel 301, the other end of the rotating rod 304 is connected to the driving component 303 (such as a rotating motor), the driving component 303 is installed on the box body 6, and the rotating rod 304 is driven to rotate during rotation, so as to realize the opening and closing function of the door panel; in addition, when the door panel 301 is in the closed state, the driving assembly 303 applies a certain self-closing force to the door panel 301, so that the sealing performance of the door panel 301 can be further ensured, and the drying reliability can be improved. By adopting the rotary sealing door plate 301, the sealing performance of the main chamber 205 is guaranteed, so that air in the main chamber 205 can be exhausted as soon as possible when nitrogen is introduced for drying, and the concentration of nitrogen in the main chamber 205 reaches a standard value. The door plate 301 is preferably made of stainless steel, and the lower edge of the door plate 301 is curled (for example, in an arc transition shape), so that the door plate 301 can be smoothly transited on the crucible tray; the inner side of the door plate 301 is provided with a heat insulation layer, so that heat in the main chamber 205 is reduced from being dissipated outwards, and meanwhile, the balance weight of the door plate 301 is increased, so that the sealing effect of the sample inlet door 3 is better ensured; of course, in other embodiments, the upper end of the door 301 may be mounted on the box 6 via a hinge (e.g., a hinge) such that the door 301 may be pushed by an external force to flip open into the box 6 or fall back to close under the action of gravity. The hinged member is hinged to the door panel 301 and the box 6, the hinge is required to ensure flexible movement, and the door panel 301 can smoothly rotate under the action of gravity. Of course, a return spring may be provided at the hinge, so that a certain self-closing force is formed between the door panel 301 and the sealing material when the door panel 301 falls back and closes, thereby further ensuring the sealing effect.

As shown in fig. 8, in the present embodiment, the blowing and heating assembly 1 includes a blowing assembly and a heating assembly 106; the air blowing component is used for accelerating gas circulation and improving drying efficiency. Specifically, the blower assembly includes a centrifugal fan 101 and a centrifugal fan blade 102; the centrifugal fan 101 is arranged on the outer side of the box body 6, and the centrifugal fan blade 102 is arranged in the heating cavity 201 and connected with the centrifugal fan 101; the inner circle of the centrifugal fan blade 102 forms an air inlet of the heating chamber 201 to communicate with the main chamber 205. The centrifugal fan 101 is a high-temperature resistant centrifugal fan 101, and can work at high temperature resistance on the premise of ensuring that the air volume and the air pressure meet the ventilation frequency, and provides power for the centrifugal fan blade 102; the circulation of gas can be accelerated when centrifugal fan blade 102 rotates at a high speed, and simultaneously, the circular ring of exhaust port 7 in the center of heating cavity 201 is just inserted into the inner circle of centrifugal fan blade 102, so that the effect of air flow exchange is better ensured. Of course, in other embodiments, axial fan blades may be used instead of centrifugal fan blades 102.

In this embodiment, the heating assembly 106 is used to heat the gas; the heating element 106 is located on one or both sides of the heating cavity 201 from the blower element. Specifically, the heating element 106 is a PTC heating sheet (PTC is short for Positive temperature coefficient), and the shape of the PTC heating sheet matches with the heating cavity 201, and occupies the cross section of the heating cavity 201. In addition, because one end of the PTC heating sheet is provided with a wiring terminal, a wind shield 105 is arranged at the wiring terminal of the PTC heating sheet in the heating cavity 201, so that the gas in the heating cavity 201 can be ensured to completely pass through the heating sheet, and the heating speed is accelerated. Of course, in other embodiments, other forms of heating fins may be used as appropriate.

In this embodiment, the centrifugal fan 101, the centrifugal fan blades 102, the PCT heating sheet, and the wind shield 105 are all mounted on the mounting plate 104 on one side of the box body 6, so as to form a component that can be integrally detached from the box body 6, which is convenient to assemble and disassemble and facilitates subsequent maintenance. In addition, the heat insulation plate 103 is laid on the inner side of the mounting plate 104, so that on one hand, the heat insulation effect is achieved, meanwhile, the influence of heat in the heating cavity 201 on the centrifugal fan 101 can be avoided, and the normal work and the service life of the centrifugal fan are ensured.

as shown in fig. 10, in the present embodiment, a temperature detection member 4 is provided in the box body 6 for detecting the temperature of the gas in the main chamber 205; the heating assembly 106 is connected to the temperature sensing member 4 for receiving the sensed temperature value of the gas and performing heating adjustment to maintain the temperature of the gas in the main chamber 205 within a constant range (e.g., 105 ℃ -110 ℃). Specifically, a normally closed contact of a temperature relay is connected in series in a power supply loop of the heating assembly 106, when the temperature detection part 4 detects that the temperature is greater than a preset value, the temperature relay is controlled to act (or the temperature detection part 4 sends a temperature signal to a control unit, and the control unit sends a corresponding control instruction after temperature judgment), and the normally closed contact is disconnected, that is, heating is disconnected; of course, the heating power of the heating assembly 106 may also be adjusted. In addition, in other embodiments, the rotation speed of the centrifugal fan 101 may be adjusted according to the temperature value, so as to accelerate the circulation and further improve the drying efficiency. Specifically, as shown in fig. 9, the temperature detection member 4 includes a fixing base 402 and a temperature probe 401, the temperature probe 401 is installed in the fixing base 402, and the fixing base 402 is detachably connected (for example, screwed) to the side wall of the return air channel 202, so that the assembly and disassembly are convenient and the maintenance is convenient.

As shown in fig. 9, in this embodiment, the air outlet of each air return channel 202 includes a plurality of vertical strip-shaped holes 203, and the length of each strip-shaped hole 203 is sequentially shortened along the air conveying direction, so that the whole air outlet is V-shaped, and hot air in the air return channel 202 can be uniformly mixed, thereby reducing the temperature difference of the air outlet; further, a mixing plate 204 is arranged at the air outlet of each air return channel 202, hot air is uniformly mixed again, the temperature difference of air at each position is further reduced, and the temperature in the whole main chamber 205 is ensured to be within a reasonable range.

In this embodiment, the outer layer of the box body 6 is laid with the heat insulation layer 601 for heat insulation and heat preservation, so as to reduce the influence of temperature channeling among the box bodies 6 arranged side by side.

In this embodiment, the shape of the box 6 is compatible with the drying operation for measuring the total moisture of the coal sample of 6mm and 13mm, and is flexibly configured according to the requirements of customers. In addition, the whole flat that is of box 6, and main cavity 205 is close to one section of heating cavity 201 and contracts to heating cavity 201 gradually, is not only convenient for gaseous circulation in main cavity 205, can guarantee simultaneously that the shape and the inner space of box 6 are minimum, reduces the consumption of nitrogen gas under the condition under guaranteeing drying efficiency, has practiced thrift the required consumptive material cost of drying operation in the total moisture survey.

S01, detecting the water vapor concentration of the main chamber 205 in the box body 6;

S02, when the detected water vapor concentration does not reach the preset water vapor concentration, controlling the retractable folding door 8 to switch to the folded state, blocking the air outlet 7, and opening the air inlet of each air return channel 202 to perform an internal circulation mode to dry the sample, as shown in fig. 2; when the detected water vapor concentration reaches the preset water vapor concentration, the telescopic folding door 8 is controlled to be switched to a stretching state, the air inlet of each air return channel 202 is blocked, and the air outlet 7 is opened to enter an external circulation mode to discharge water vapor, as shown in fig. 3.

According to the heat flow circulation control method based on the drying box, the evaporation of water inside and outside the sample is accelerated to form vapor through the internal circulation heating mode, the consumption of nitrogen in the main chamber 205 is greatly reduced, meanwhile, the power of the heating sheet can be greatly reduced through the internal circulation mode, and the purpose of energy conservation can be achieved; when the concentration of the water vapor in the main chamber 205 reaches or approaches to the saturated vapor pressure, the folding state is switched to the stretching state through the telescopic folding door 8, so that the switching from the internal circulation mode to the external circulation mode is realized, the discharge of the water vapor is accelerated through the exhaust port 7, and the drying efficiency of subsequent samples is further improved; through the matching of the internal and external circulation modes, the sample is quickly dried.

In this embodiment, in step S01, the water vapor concentration of the main chamber 205 in the box 6 is obtained by a water vapor concentration detecting member (not shown in the figure) or by the opening time according to the internal circulation pattern in the box 6. In step S02, after entering the external circulation mode, the mode is switched to the internal circulation mode after a predetermined time, and then the circulation is performed until the drying is completed.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make numerous possible variations and modifications to the present invention, or modify equivalent embodiments to equivalent variations, without departing from the scope of the invention, using the teachings disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention should fall within the protection scope of the technical scheme of the present invention, unless the technical spirit of the present invention departs from the content of the technical scheme of the present invention.

Claims

1. The drying box is characterized by comprising a box body (6) and a main cavity (205) formed by enclosing the box body (6), wherein a sample inlet door (3) is arranged at one end of the box body (6), a heating cavity (201) communicated with the main cavity (205) is arranged at the end, opposite to the sample inlet door (3), of the sample inlet door (3), a blast heating assembly (1) is arranged in the heating cavity (201), return air channels (202) are arranged on two sides of the main cavity (205), air inlets of the return air channels (202) are communicated with the heating cavity (201), air outlets of the return air channels (202) are located on two sides close to the sample inlet door (3) and are communicated with the main cavity (205), and the main cavity (205), the heating cavity (201) and the two return air channels (202) are communicated in sequence to form an internal circulation air duct (106); an air inlet assembly (5) facing the heating cavity (201) is arranged on one side of the sampling door (3) of the main cavity (205); an air outlet (7) is formed in the heating cavity (201) at an air inlet of each air return channel (202), and a telescopic folding door (8) which is switched between a folding state and a stretching state is arranged at the air outlet (7); when the telescopic folding door (8) is in the folded state, the exhaust port (7) is blocked by the telescopic folding door (8) in the folded state, and the air inlet of each air return channel (202) is opened to carry out an internal circulation mode; when the telescopic folding doors (8) are in the stretching state, the air inlet of each air return channel (202) is blocked by the telescopic folding doors (8) in the stretching state, and the air outlet (7) is opened to carry out an external circulation mode.

2. The drying cabinet of claim 1, characterized in that the retractable folding door (8) comprises a plurality of door bodies (801) hinged in sequence, wherein the door body (801) on one side is hinged on the inner wall of the cabinet (6), the door body (801) on the other side is connected with a driving member (802), and the driving member (802) moves linearly to drive the door body (801) to switch between the folding state and the stretching state.

3. The drying cabinet according to claim 2, characterized in that the drive member (802) comprises a rotary motor and a screw mechanism, and the rotary motor is connected with the door body (801) through the screw mechanism.

4. A drying cabinet according to claim 1, 2 or 3, characterized in that the air intake assembly (5) comprises a nitrogen gas intake unit (502), an air intake unit (503) and a strip gas distributor (501), the gas distributor (501) being arranged along the arrangement direction of the injection door (3); the nitrogen gas inlet unit (502) and the air inlet unit (503) are respectively connected with the gas distributor (501), and the nitrogen gas inlet unit (502) and the air inlet unit (503) are interlocked.

5. The drying cabinet according to claim 4, characterized in that the nitrogen gas inlet unit (502) comprises a nitrogen gas source (5021), a pressure reducing valve (5022), a nitrogen gas electric control switch (5023) and a drying module (5024) which are connected in sequence, wherein the drying module (5024) is connected with one end of the gas distributor (501); the air inlet unit (503) comprises an air electronic control switch (5031), and the air electronic control switch (5031) is connected with the other end of the air distributor (501); the nitrogen electronic control switch (5023) and the air electronic control switch (5031) are electrically or mechanically interlocked.

6. the drying cabinet according to claim 1, 2 or 3, wherein the sample inlet door (3) comprises a door panel (301), a rotating rod (304) and a driving assembly (303), one end of the door panel (301) is rotatably mounted on the cabinet (6) through the rotating shaft, one end of the rotating rod (304) is connected with the door panel (301), the other end of the rotating rod is connected with the driving assembly (303), and the driving assembly (303) is used for driving the rotating rod (304) to rotate so as to open and close the door panel (301), and providing a certain self-closing force when the door panel (301) is closed.

7. Drying cabinet according to claim 1 or 2 or 3, characterized in that the sample door (3) comprises a door panel (301), the upper end of the door panel (301) is mounted on the cabinet (6) by a hinge such that the door panel (301) is pushed by an external force to flip open into the cabinet (6) or fall back closed under the effect of gravity.

8. A drying box according to claim 7, characterised in that the lower edge of the door panel (301) is in the form of a circular arc transition.

9. A drying box according to claim 1 or 2 or 3, characterized in that the blast heating assembly (1) comprises a blast assembly and a heating assembly (106); the blower assembly comprises a centrifugal fan (101) and a centrifugal fan blade (102); the centrifugal fan (101) is arranged on the outer side of the box body (6), and the centrifugal fan blade (102) is arranged in the heating cavity (201) and is connected with the centrifugal fan (101); the main chamber (205) is provided with an air inlet of the heating chamber (201) at the inner circle of the centrifugal fan blade (102).

10. A drying cabinet according to claim 9, characterized in that the heating assembly (106) is located at one or both sides of the heating chamber (201) to the blowing assembly for heating the gas.

11. A drying box according to claim 9, characterized in that the heating assembly (106) is a PTC heating plate.

12. A drying cabinet according to claim 11, characterized in that the shape of the PTC heating strips matches the shape of the heating cavity (201), and the heating cavity (201) is provided with a wind deflector (105) at the wiring terminals of the PTC heating strips.

13. A drying cabinet according to claim 9, characterized in that the blowing assembly and the heating assembly (106) are both located on a mounting plate (104) on one side of the cabinet (6).

14. Drying box according to claim 13, characterised in that the mounting plate (104) is laid with insulation panels (103) on the inside.

15. A drying box according to claim 9, characterized in that inside said box (6) there is provided a temperature detection member (4) for detecting the temperature of the gas inside said main chamber (205); the heating assembly (106) is connected with the temperature detection part (4) and is used for receiving the detected gas temperature value to carry out heating adjustment so as to maintain the gas temperature in the main chamber (205) within a constant range.

16. The drying cabinet of claim 15, characterized in that the temperature detecting member (4) comprises a fixing seat (402) and a temperature measuring probe (401), the fixing seat (402) is detachably connected to the side wall of the return air channel (202), and the temperature measuring probe (401) is installed in the fixing seat (402).

17. A drying box according to claim 1, 2 or 3, characterized in that the air outlet of each return air channel (202) comprises a plurality of vertical strip-shaped holes (203), and the length of each strip-shaped hole (203) is shortened in turn in the air conveying direction.

18. A cabinet according to claim 17, wherein a flow mixing plate (204) is provided at an air outlet of each of the return air passages (202).

19. A drying box according to claim 1, 2 or 3, characterized in that the outer layer of the box body (6) is laid with heat insulating and insulating layer (601).

20. A drying cabinet according to claim 1 or 2 or 3, characterized in that a section of the main chamber (205) adjacent to the heating chamber (201) gradually converges towards the heating chamber (201).

21. A drying cabinet according to claim 1, 2 or 3, characterized in that a concentration detector is arranged in the main chamber (205) for detecting the water vapour concentration for controlling the telescopic folding door (8) to switch between the folded state and the stretched state.

22. A heat flow cycle control method based on the drying box of any one of claims 1 to 21, characterized by comprising the following steps:

S01, detecting the water vapor concentration of the main chamber (205) in the box body (6);

S02, when the detected water vapor concentration does not reach the preset water vapor concentration, controlling the telescopic folding door (8) to be switched to a folding state, blocking the exhaust port (7), and opening the air inlet of each air return channel (202) to dry the sample in an internal circulation mode; when the detected water vapor concentration reaches the preset water vapor concentration, the telescopic folding door (8) is controlled to be switched to a stretching state, the air inlet of each air return channel (202) is blocked, and the air outlet (7) is opened to enter an external circulation mode to discharge water vapor.

23. The heat flow cycle control method according to claim 22, characterized in that in step S01, the water vapor concentration of the main chamber (205) in the box (6) is obtained by the water vapor concentration detection member or by the opening time according to the internal circulation pattern in the box (6).

24. The heat flow cycle control method of claim 22, wherein in step S02, after entering the external cycle mode, the mode is switched to the internal cycle mode after a predetermined time.