CN211575695U

CN211575695U - Dynamic vacuum system with chamber balancing

Info

Publication number: CN211575695U
Application number: CN201922427077.8U
Authority: CN
Inventors: 韩荣献; 董芳
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-12-28
Filing date: 2019-12-28
Publication date: 2020-09-25
Anticipated expiration: 2029-12-28
Also published as: CN211575694U; CN110926120B; CN110926120A

Abstract

The invention relates to a chamber-balanced dynamic vacuum system and a material drying method. In particular to liquid concentration equipment, liquid materials are placed in a vacuum working chamber (10), a medium inlet (11) and a steam outlet (12) are arranged on the vacuum working chamber (10), and an auxiliary heat exchanger (33) in the vacuum working chamber (10) is used for heating the liquid materials and the medium steam; the vacuum balance chamber (20) is provided with a condensing heat exchanger (23) for condensing steam flowing into the vacuum working chamber and is connected with a vacuum pump (25); the invention relates to a vacuum drying, heat treatment and evaporation system with water vapor as a heat-conducting medium, which is used for liquid evaporation and vacuum heat treatment and changes the transformation utilization and use efficiency of the traditional vacuum environment.

Description

Dynamic vacuum system with chamber balancing

Technical Field

The utility model relates to a vacuum system, concretely relates to dynamic vacuum system that room balance that has controllable heat-conducting medium.

Background

The drying requirement almost extends to most industrial fields, and while the research and development of drying technology are continuously carried out, the attention should be paid to improving efficiency, effectively utilizing energy and reducing adverse effects on the environment. Compared with the conventional drying technology, the vacuum drying has the advantages of high efficiency, energy conservation and less emission, and the heat exchange can not be carried out in the vacuum environment because the known vacuum environment has no heat-conducting medium. In a vacuum environment, the boiling point of water continuously decreases along with the increase of the vacuum degree, according to the relation data of the water vapor saturation temperature and the pressure, the boiling point of water with the relative vacuum degree of 40kpa is 85.5 ℃, the boiling point of water with the relative vacuum degree of 60kpa is 75 ℃, the boiling point of water with the relative vacuum degree of 80kpa is 60.1 ℃, and the boiling point of water with the relative vacuum degree of 90kpa is only 45.3 ℃. If the heat-conducting medium can be in a vacuum state, the heat can be conducted to the dried material, so that the energy is saved, and the drying efficiency of the material is greatly improved.

The traditional drying method mostly adopts hot air convection drying under normal pressure, has long period, low efficiency and high energy consumption, and the traditional drying method is not repeated. The current advanced drying technology is vacuum drying, taking wood drying as an example: vacuum high-frequency drying, vacuum hot plate drying, batch or pulse type vacuum drying, which is a type of vacuum convection drying, is mostly adopted at present. However, all vacuum drying vacuum needs to be maintained by continuous operation of a vacuum pump at present, water vapor in a drying chamber is inevitably pumped and exhausted by the vacuum pump, the water vapor is a heat-conducting medium and is a carrier of heat required by the drying process, the heat-conducting medium and the vacuum cannot coexist at the same time by the vacuum pump, the steam pumping and exhausting not only causes loss of the heat-conducting medium and wastes a large amount of energy, but also cannot establish thermodynamic balance so as to cause that the heat cannot be scientifically calculated and the drying process cannot be reasonably controlled, so that all vacuum drying technologies at present are determined to be not scientific and reasonable vacuum drying technologies, and the problem that a vacuum system can scientifically and reasonably use and control the heat-conducting medium cannot be solved in the domestic and foreign drying industries and in some industries using vacuum systems so far.

For the definition of vacuum drying and the authoritative theoretical explanations and theoretical calculations reference may be made to: authors of general higher education 'fifteen' national level planning teaching material, and teaching material for planning wood science and engineering major in colleges and universities 'wood processing technology': tensioning to refine hundred; discussion of theoretical calculation of a heating system of wood vacuum drying equipment, Yisonlin, Zhanguanguang, Shanzhen, Yuqingwei and chemical machinery 2010, 37(3) 312-315; a model and an application initial exploration of the water evaporation rate of the surface of the wood under the vacuum condition are correct bin, plum sail, Yisonlin and Zhangguang, which are published by Beijing university of forestry, 2010 and 32(6), 105-108. In the teaching material of national academy of higher education, namely Wood processing engineering, professor Zhang Kong Bai of Nanjing university of forestry gives authoritative definition and explanation for wood vacuum drying, and the used method is that a vacuum pump is connected with a condenser to directly discharge wet steam generated by wood drying so as to maintain the vacuum degree of the system; the authors of the papers refer to several professors of Beijing forestry university such as Yi pine forest, all of which are domestic famous drying experts, and in the papers, a vacuum drying mode in which a vacuum pump is connected with a condenser and water vapor is directly pumped out to maintain vacuum is used as a vacuum drying technology for theoretical research, and a theoretical calculation model is provided. Therefore, the existing vacuum drying technology is defined by directly removing water vapor evaporated from the material by using a vacuum pump and maintaining the vacuum by using the vacuum pump.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide the balanced dynamic vacuum system in room to solve the problem of controllable heat-conducting medium's vacuum drying under vacuum state. Under this preceding technical background, utility model room balance dynamic vacuum system makes the novelty change to vacuum drying technique, can realize really having controllable heat-conducting medium's vacuum drying system, does not use the vacuum pump but the heat transfer of system steam itself to establish the balance to having kept stable and controllable heat-conducting medium, greatly improved dry efficiency and product quality stability, saved a large amount of energy, opened up a new situation for whole dry trade.

The technical route of the utility model is that the characteristic of utilizing water and vapor vacuum pressure to correspond temperature saturation point heat absorption, exothermic phase transition under vacuum state constitutes a confined thermal balance system, reaches the vacuum state under not using the vacuum pump, with the stable controllable dynamic vacuum system that phase transition maintains. The system is divided into two parts, one part is a part for absorbing heat and changing phase and evaporating moisture, and is called as a vacuum working chamber and a drying chamber for materials; one part is the part of the vapor exothermal condensation phase change condensation, which is called a vacuum balance chamber. The steam outlet of the vacuum working chamber is connected with the steam inlet of the vacuum balance chamber, and the steam generated in the drying process of the system generates phase change to establish pressure balance between the two chambers and also form heat balance. See figure 6: schematic diagram of heat balance and pressure balance.

Firstly, after the materials are preheated, medium steam exchanges heat with the materials, moisture in the materials is subjected to phase change at a saturation temperature point corresponding to vacuum pressure to generate steam, the volume is rapidly increased, the vacuum degree is reduced, the steam enters a vacuum balance chamber, the steam in the balance chamber is contacted with a condensation pipeline to release heat and be subjected to phase change condensation to form water, the volume is rapidly reduced, the vacuum degree is increased, and the vacuum working chamber and the vacuum balance chamber are kept at the same pressure by utilizing the special process of steam phase change to establish a closed heat balance system. In the closed balance system, all medium steam for drying and steam evaporated from materials orderly flow into the vacuum balance chamber from the vacuum balance chamber to perform condensation heat exchange to establish a heat balance, so that the pressure balance is achieved, and the balance cannot be established by pumping with a vacuum pump. Because the condensation phase change of the steam is generated when the steam is in contact heat exchange with the pipeline of the condensation heat exchanger and cannot be condensed before the steam is in contact with the condensation pipeline, the steam temperature of the vacuum working chamber and the steam temperature of the vacuum balance chamber are basically the same, the system can be used as an isothermal and isobaric system, and the properties of the steam in the two chambers are the same when the temperature T and the pressure P of the system are fixed. According to the inference of avogalois law, the thermal equilibrium system is a mass-balanced, pressure-balanced, heat-balanced thermal equilibrium system.

Firstly, a chamber balance dynamic vacuum system balance element:

the heat is balanced.

The expression for heat balance can be written as: j f n s q + q ═ q + q

qj heat of medium steam entering vacuum working chamber

Heat consumed by qf auxiliary heating heat exchanger

Heat absorbed by qn vacuum balance chamber condenser

qs vacuum balance chamber condensed water sensible heat

The medium steam is usually opened to increase the heat-conducting medium when the concentration of the medium is not enough to provide enough heat in the initial stage and the drying deceleration stage, so that the heat provided by qj is little; in the drying constant speed period qj equal to 0, part of steam evaporated from the water in the material enters the air channel for circulation, and part of the steam entering the air channel is used for reheating to improve the superheat degree of a steam medium, so that a large amount of medium steam is saved. Therefore, during the dry constant speed period, assuming that the vacuum working chamber and the vacuum balance chamber are both adiabatic, the expression for heat balance can be written as:

qf-qn + qs, i.e.:

the heat provided by the auxiliary heater of the vacuum working chamber is the heat absorbed by the condenser condensed water of the vacuum balance chamber and the sensible heat of the condensed water

It follows that the balance of the system is determined by the heat balance between the auxiliary heating heat exchanger of the working chamber and the condensing heat exchanger of the balancing chamber, regardless of the amount of steam, i.e. in the case of equilibrium, the same amount of steam will remain in equilibrium regardless of the amount of steam produced by the working chamber as long as the same amount of steam condenses in the balancing chamber.

The vacuum pressure of a chamber balance dynamic vacuum system can be maintained by balance without continuous vacuum pumping of a vacuum pump, the vacuum degree of the system only depends on the preset vacuum degree before work, namely the vacuum pressure value P of static vacuum, the static vacuum pressure P is set by the vacuum pump to evacuate the system in advance, when the dynamic vacuum is established, the condensing speed of a controllable balance chamber is always greater than the steam speed of a working chamber, the vacuum degree of the working chamber can be continuously increased, the system is balanced when the steam condensing amount is controlled to be equal to the steam generating amount, the balance is established until the required vacuum pressure value Pv is reached, and the value of Pv is always less than P. It follows that by controlling the rate of condensation, Pv can be any value in the range 0 to P at which equilibrium can be established and maintained.

Since the chamber equilibrium dynamic vacuum system is a thermodynamic equilibrium, after Pv is determined, the steam temperature T is also determined, and the water vapor property is the saturated steam in the Pv, T state. It follows that the control of the dynamic vacuum system conditions is determined by the control of the condensing system. In a chamber balance dynamic vacuum system, orderly flowing water vapor is a factor for maintaining heat balance and is a heat-conducting medium for drying materials in a vacuum state, so that the problem that the drying materials in the vacuum state cannot exchange heat is thoroughly solved. In the vacuum balance chamber, heat can be recycled by heat exchange of condensed water and water vapor. Meanwhile, the energy utilization rate of the chamber balance dynamic vacuum system is very high, no improper heat consumption exists except for self heat dissipation of equipment, the efficiency and the energy consumption are incomparable with other vacuum drying technologies and methods, and the creation of the chamber balance dynamic vacuum system is an innovative revolution of the vacuum drying technology.

Steam mass balance:

the chamber balanced dynamic vacuum system is a mass balanced thermal balance system. The sum of the mass of the steam generated by drying the materials and the mass of the heat-conducting medium steam supplemented by the heat-conducting medium steam pipeline is equal to the mass of the steam condensed by the condensing heat exchanger in the balancing chamber. When the system is balanced in pressure Pv, the steam of the two chambers is saturated steam with the same property, in the stage of drying constant speed, the evaporation capacity of the steam of the vacuum working chamber is equal to the condensation capacity of the steam of the vacuum balancing chamber, therefore, through the effective control of the condensation rate, during dynamic vacuum balance, the steam generation capacity of the working chamber and the steam condensation capacity of the balancing chamber are in quality balance, the increment does not influence the balance, the steam generation capacity is determined by the heat provided by the auxiliary heating heat exchanger, the control of the condensation efficiency determines the system pressure and the quality balance, the heat exchange efficiency of the condenser is designed to be always higher than that of the auxiliary heating heat exchanger, the effective control of the condensation efficiency can be ensured, the stability of the system pressure is ensured, and the balance of the system is also ensured. Whilst this allows maximising the efficiency with this feature for vacuum drying.

Secondly, a system balance structure:

the chamber balance dynamic vacuum system consists of a vacuum working chamber and a vacuum balance chamber.

Vacuum working chamber heat

The vacuum working chamber is the core part of the system and is the place for drying the materials, and the auxiliary heating heat exchange area of the working chamber plays a key role in drying the materials and directly influences the quality, cost, efficiency and other aspects of the product.

The heat required by drying is mainly provided by an auxiliary heating heat exchanger, because the drying of the material in a vacuum state is a heat and mass transfer process, the larger the negative pressure is, the larger the pressure gradient inside the material is, the speed of the heat exchange phase change of the moisture overflowing to the surface and the heat-conducting medium is greatly accelerated, through heating, the heat-conducting medium steam is increased by a certain superheat degree, the superheat degree can ensure that the heat enough to exchange with water generates phase change, and meanwhile, the reverse phase change can not be generated due to the heat release of the heat-conducting medium, different vacuum pressures and temperature effects are different, the pressure is high, the boiling point of water is also high, the boiling temperature is reduced by decompression operation in order to reduce the boiling point of the water, and under the corresponding temperature, when the steam pressure of the water is equal to the total pressure of the water surface, the boiling can occur.

The energy balance relationship of the vacuum chamber is now described by way of example in conjunction with the heat transfer principle:

suppose that 100kg of the material to be dried is to be dried from an initial moisture content of 80% to a moisture content of 10%. The condition is assumed as follows: the initial temperature of the material was 21 c,

the specific heat capacity of the material, c1, of 3.8kj/kg DEG C water, c2, of 4.168kj/kg DEG C

Initial weight (1-80%) final weight (1-10%) final weight 100kg 0.2/0.9 22.2kg, so water 100-22.2-77.8 kgm' needs to be removed 77.8 kg.

(1) When the pressure p is 60kpa, the temperature T is 85.6 ℃, the latent heat of vaporization r is 2293.9kj/kg

Heat required to dry 100kg of material: q-m-c 1-t + m' r-100X (85.6-21) X3.8+77.8X 2293.9-203013.4 kj-2609.4 kj/kg-the heat required for evaporation of water

(2) When the pressure p is 20kpa, the temperature T is 60 ℃ latent heat of vaporization r is 2358kj/kg heat energy of 60 ℃ with the temperature increased for vaporizing 100kg of materials + latent heat of water under the pressure of 20kpa

The heat transfer area of 19827.4kj/77.8kg 2549kj/kg. heat transfer required for drying per kg of water at 100x (60-21) 3.8+77.8x 2358 x 19827.4kj can be according to the formula:

Q K A t

A＝Q/A△t

a-heat exchange area m 2; q-total heat exchange amount w; k-heat transfer coefficient w/m 2K; Δ t — the temperature difference K between the two fluids; the logarithmic mean temperature difference is obtained by using the temperature difference of the two fluids. The heat exchange coefficient is different according to the heat exchange methods of different types and materials, and can be calculated by referring to a heat exchange coefficient table.

As can be seen from the above, the lower the pressure, the less heat energy is consumed for drying, and the energy-saving and efficient practical situation of vacuum drying is fully reflected. The auxiliary heat exchanger needs to be selected in consideration of shell heat dissipation and other unknown heat losses, an amplification factor is considered in heat calculation, the total heat in normal conditions is multiplied by a coefficient of 1.2, the drying characteristics of materials are combined, blind seeking cannot be achieved, the indoor balance dynamic vacuum system is different from other drying technologies, referential experience data are few, much experience data need to be summarized in practice, a reasonable drying period is made, years of experience of the inventor is realized, the drying period made by the accumulated experience of the traditional drying method is usually more than 10 times that of the indoor balance dynamic vacuum system, and therefore the drying period of the inventor is recommended to be made by dividing the traditional drying period by 5-10 and then adjusted in practice.

Vacuum balance chamber

The vacuum balance chamber is a necessary link of a chamber balance dynamic vacuum system and is fundamentally different from other vacuum drying methods.

The inside condensation tube bank that is equipped with of vacuum balance room, the comdenstion water can be stored to the bottom, condensation tube bank and condensation surface of water leave the certain distance and can not contact the condensation surface of water, vacuum balance room is room balance dynamic vacuum system's control pivot, through the control to the condensation speed, can decide the value of vacuum pressure PV, the control to the speed of condensation will be considered during the design, it is the key of decision system pressure P, temperature T, so, condenser heat exchange efficiency will be greater than auxiliary heater heat exchange efficiency during the design installation of equipment. When the dynamic vacuum is established, the steam condensation speed of the balance chamber is controlled to be always greater than the steam generation speed of the working chamber, the vacuum degree of the working chamber can be continuously and slowly increased, the steam condensation amount is controlled to control a vacuum pressure value Pv to establish balance, the value of Pv is smaller than a static vacuum pressure P, and Pv is the vacuum pressure value of the dynamic balance. The vacuum balance chamber is arranged, so that all water vapor in the system can be subjected to closed heat exchange, a heat balance system is established, the heat balance system ensures that the water vapor flows orderly in a vacuum environment, and the chamber balance dynamic vacuum system becomes a vacuum system with a heat-conducting medium flowing orderly all the time. Energy balance relation of the vacuum balance chamber:

Q-Q latent + Q-Y

Q- - - -heat flow into the vacuum balance chamber; q latent heat- -cooling water absorbs latent heat of gasification; q shows- -sensible heat of condensed water

The condensing area formula is the same as the area formula of the vacuum working chamber, and A is Q/A delta t

The flow rate of the condensed water can be obtained by dividing the total heat exchange quantity of the condensed water by the heat absorption quantity of cooling water per kilogram, the inlet and outlet temperatures and the flow rate of the condensed water are key data for controlling the pressure of the system, the condensing mode is correctly selected in application, and the heat exchange area is enough obtained, so that the best condensing efficiency of the system is ensured. Since the water vapor can not be completely contacted with the condensing pipe for heat exchange, the vacuum balance chambers can be preferably connected in a two-stage or multi-stage scheme and in a serial or parallel connection mode to ensure that the water vapor can be more completely exchanged with heat.

Thirdly, the concrete scheme of the utility model:

the utility model discloses a concrete technical scheme do: the chamber balance dynamic vacuum system comprises a vacuum working chamber, an auxiliary heating heat exchanger, a condensing heat exchanger and a vacuum balance chamber, wherein a material to be dried is placed in the vacuum working chamber, a medium steam inlet and a steam outlet are formed in the vacuum working chamber, the auxiliary heating heat exchanger is installed in the vacuum working chamber and used for heating medium steam and exchanging heat with the material to be dried, and the vacuum working chamber is communicated with the vacuum balance chamber through a steam outlet and a steam outlet valve; the vacuum balance chamber is provided with a condensation tube bundle, the vacuum balance chamber is connected with a vacuum pump, a water outlet is formed in the bottom of the vacuum balance chamber, the condensation heat exchanger condenses steam flowing into the vacuum balance chamber in the vacuum working chamber, the steam is condensed into water through phase change, the condensed water is gathered at the bottom of the vacuum balance chamber and is discharged through the water outlet, and the chamber balance dynamic vacuum system is a closed system, so the condensed water must be pumped and discharged by a water pump.

When the chamber balance dynamic vacuum system works, firstly, a steam outlet valve is opened, a vacuum working chamber is communicated with a vacuum balance chamber, the vacuum working chamber and the vacuum balance chamber are vacuumized to a required range through a vacuum pump, and then the vacuum pump is closed; the drying to liquid material, the vacuum chamber is vertical to be placed, and auxiliary heat exchanger installs the lower part in the vacuum chamber, and the liquid dry material of treating pours into from the medium entry of vacuum chamber into to directly treat the water in the dry material by auxiliary heat exchanger and heat, and water evaporates for vapor at the temperature saturation point that vacuum pressure corresponds, and vapor enters into the balance chamber condensation from steam outlet, and the steam and the condensation heat exchanger that get into the vacuum balance chamber contact the heat transfer, and vapor condenses for water at the temperature saturation point phase transition that corresponds with vacuum pressure. Condensed water is gathered at the bottom of the vacuum balance chamber and is discharged through a water pump, the cooling water flow of the condenser is controlled, the pressure of the vacuum working chamber is kept to be larger than or equal to the pressure of the vacuum balance chamber, namely the vacuum degree of the vacuum balance chamber is larger than or equal to the vacuum degree of the vacuum working chamber, after the pressure of the vacuum working chamber and the pressure of the vacuum balance chamber are balanced, the vacuum pressure balance of the system is achieved, and the dynamic vacuum system starts to operate for drying materials.

Generally, can need to install condensation heat exchanger inside the vacuum balance room according to equipment structure and condensation, work as condensation heat exchanger installs when the vacuum balance room is inside, and the medium steam that is mixed with steam flows into the vacuum balance indoor back from the vacuum studio, through the indoor condensation heat exchanger of vacuum balance with steam condensation phase change for the comdenstion water.

Generally, set up a vacuum balance room cooperation vacuum studio and establish the balanced dynamic vacuum system in room can, especially, can be according to equipment structure and vacuum studio and the balanced needs of vacuum balance room pressure, will the vacuum balance room sets up to multistage balance room, constitutes multistage balance room by two and more than two vacuum balance rooms series connection promptly, and the vacuum pump interface of preceding vacuum balance room and the medium steam inlet intercommunication of next vacuum balance room to bottom UNICOM between the condensate water storage room, the vacuum pump interface and the vacuum pump connection of last vacuum balance room.

Generally, can be according to vacuum studio heat transfer needs, the auxiliary heat exchanger that the installation is fit for, in particular, the utility model discloses a mode of the auxiliary heat exchanger of concrete vacuum studio installation, the auxiliary heat exchanger of vacuum studio inner wall installation separates through wind channel baffle and the drying chamber of placing the material of treating to dry, and medium steam flows into the drying chamber and treats the material of drying and carry out the heat transfer after getting into the wind channel between auxiliary heat exchanger and wind channel baffle from the medium entry of vacuum studio and heating.

The steam that utilizes steam for the high efficiency gets into with the inflow of reducing medium pipeline steam with the energy saving, promotes the steam that the part evaporates and gets into the wind channel heat transfer and also becomes medium steam to accelerate the flow velocity of medium steam in the vacuum studio, the inside preferred fan of installing of vacuum studio.

Generally, treat that dry material can take and directly place in vacuum chamber, or set up the material frame in vacuum chamber, will treat dry material and place the mode on the material frame, very much, the utility model discloses a treat that dry material places conveniently, the utility model discloses a concrete dry material mode of placing of treating, install the skip track in the vacuum chamber, treat dry material and pack into behind the material dolly along the skip track in pushing into vacuum chamber.

In order to facilitate the discharge of condensed water in a vacuum working chamber for some materials to be dried, a condensed water tank is arranged at the bottom of the vacuum working chamber.

Generally, set up a vacuum studio cooperation vacuum balance room and establish the balanced dynamic vacuum system in room can, especially, can be according to equipment structure and vacuum studio and vacuum balance room pressure balance needs, will the vacuum studio is multistage evaporating chamber, establishes ties by two and more than two vacuum studio promptly and constitutes multistage evaporating chamber, is linked together bottom leakage fluid dram and the medium entry with the vacuum studio through the water pump between each vacuum studio.

Generally, can be according to dynamic vacuum system equipment control complexity, take manual or automatic control, in particular, the utility model discloses preferentially install magnetism in vacuum balance room bottom and turn over board level gauge, gas flowmeter and medium inlet valve are installed in proper order to the medium entrance of vacuum studio, install the vacuum pump valve between vacuum balance room and the vacuum pump, and the drain outlet department of vacuum balance room bottom installs drain pump connection valve, liquid flowmeter and drain pump to through the switch of each valve of control system control and pump.

Advantageous effects

The utility model discloses dynamic vacuum system of room balance is through establishing thermodynamic equilibrium, be formed with the vapor of orderly flow and do the vacuum drying of heat-conducting medium, heat treatment and vaporization system, be the vacuum system of gas convection heat transfer mode, constant vacuum pressure is being kept throughout under vacuum state, there is vapor to do the heat-conducting medium, in the implementation process, because with the heat transfer of material, the moisture of material is the gasification of low temperature critical point, moisture that is different from conventional drying volatilizees and evaporates, the improvement of efficiency is the improvement of geometric order of magnitude. The utility model discloses a controllable gaseous state heat-conducting medium's vacuum system is to traditional huge breakthrough that utilizes the vacuum to carry out drying method, has greatly changed transformation utilization and availability factor to traditional vacuum environment. The drying mode of gas convection heat transfer in the vacuum state improves the efficiency of drying at normal temperature by several times or even more than ten times.

Particularly, the utility model discloses a discovery has two kinds of balanced states of static balance and dynamic balance between vacuum working chamber and the vacuum balance chamber in the drying process, the static balance pressure is P, so-called dynamic balance means opening medium entry valve, medium steam gets into the vacuum working chamber of presetting a certain vacuum degree through catch water, according to gas flowmeter feedback data, adjust steam flow to the required flow of medium drying heat transfer, vacuum working chamber pressure P1 increases, the vacuum degree reduces, steam gets into the vacuum balance chamber condensation phase change, vacuum balance chamber pressure P2 reduces, the vacuum degree rises, P1 ≧ P2 > P, control system adjusts steam flow and condensation speed between two rooms, keep P1 ≧ P2, form the chamber balance of dynamic vacuum, when forming dynamic balance between vacuum working chamber and the vacuum balance chamber, the vacuum pump will be in the closed state, namely, the dynamic vacuum does not need a vacuum pump to work, and the thermodynamic balance between the two chambers maintains the vacuum stability. The steam is changed into superheated steam through heat exchange between the air duct and the auxiliary heat exchanger, then heat is transferred to the material, moisture in the steam heat release material absorbs heat to generate low-temperature boiling point evaporation, the steam flows to the balance chamber to be condensed and changed into water, the moisture in the material is continuously and rapidly evaporated, and the dryness of the superheated steam is 100%, so that the moisture in the material can be gasified all the time until the humidity sensor displays the required moisture content of the material, and the whole process is controlled by the intelligent control system after the work is finished. Therefore, the chamber balance of the dynamic vacuum greatly improves efficiency and saves energy compared with the prior art, and in addition, continuous production of superheated steam drying is realized, and the vacuum environment inside can be spontaneously maintained through the vacuum balance chamber.

The vacuum balance chamber is very different from the prior art condenser compared to the prior art cooling water tank. The operation structure mode of the existing vacuum drying system is as follows: a vacuum chamber working chamber, a condenser, a water storage tank and a vacuum pump. The vacuum pump is a main structural unit, the vacuum pump directly discharges water vapor, the water storage tank collects condensed water, main work is also completed by the vacuum pump, heat balance cannot be established, and the system can only continuously work through the air pump to maintain vacuum. Therefore, the prior art structure and operation has many disadvantages: 1. pumping out water vapor to cause heat emission, balance cannot be established, and only a vacuum pump can be used for maintaining vacuum; 2. the vacuum pump exhausts water vapor to cause serious shortage of heat-conducting media, and moisture in materials without the heat-conducting media cannot exchange heat, so that drying cannot be carried out or the drying efficiency is greatly reduced; 3. the vacuum pump consumes a large amount of energy in continuous operation, and is not easy to maintain; 4. the pumping and draining of water vapor causes great heat loss and is not beneficial to environmental protection; 5. the uncontrollable heat and heat transfer media can lead to uncontrollable overall drying process. This is also the reason why the current vacuum drying technology has not been widely applied in both international and domestic situations.

The chamber balance dynamic vacuum system operates the structural mode:

the vacuum chamber working chamber + the vacuum balance chamber + the heat balance. In the operation structure of the chamber balance dynamic vacuum system, the vacuum pump is not a main structural unit, the vacuum pump is used only before the work is started, the vacuum pump is closed after the static vacuum is established, the machine halt state is always kept, and the vacuum is maintained through the heat balance of the system. Structurally, the vacuum balance chamber is provided with a condensation tube bundle and has a water storage chamber function, enough space is provided for storing condensed water so as to discharge the condensed water at regular time, and enough space ensures that the condensation tube bundle has enough large heat exchange area and heat exchange efficiency, thereby ensuring the balance relation between evaporation and condensation of steam. The vacuum working chamber and the vacuum balance chamber are a closed system space, a thermal balance state is formed between the two chambers, the condensation speed is controlled, on the basis of the static vacuum pressure P, the steam condensation speed of the balance chamber is controlled to be always larger than the steam generation speed of the working chamber, the vacuum degree of the working chamber can be continuously and slowly increased, the steam condensation amount is controlled, the vacuum pressure value can be controlled to establish balance at any working pressure Pv, the value of Pv is smaller than the static vacuum pressure P, and Pv is the vacuum pressure value of dynamic balance. Establishing heat balance is the key to the system, and controlling condensing efficiency is the core of balance. In order to make steam fully condense, a multistage vacuum balance chamber is designed, the space of the vacuum balance chamber is larger, the heat exchange area is larger, steam is easier to fully contact with a cold wall for complete condensation, dynamic pressure balance is more favorably formed, the vacuum is maintained by means of pressure balance generated by condensation, the vacuum pump does not work, and the vacuum pump only extracts initial vacuum.

The theory of the room balance dynamic vacuum environment that utility model people first find can be summarized as follows:

a closed heat balance system is constructed by utilizing the characteristics of heat absorption and heat release phase change of corresponding temperature saturation points of water and water vapor in a vacuum state, and a stable and controllable dynamic vacuum system is maintained by using phase change. The system is divided into two parts, wherein one part is a part for absorbing heat, changing phase and evaporating moisture, is called a vacuum working chamber and is also a drying chamber of materials, and the other part is a part for releasing heat, condensing, changing phase and condensing water vapor, and is called a vacuum balance chamber. The steam outlet of the vacuum working chamber is connected with the steam inlet of the vacuum balance chamber, and the steam generated in the drying process of the system generates phase change to establish heat balance between the two chambers. The vacuum balance chamber is arranged, so that all water vapor in the system can be subjected to closed heat exchange, a heat balance system is established, the heat balance system ensures that the water vapor flows orderly in a vacuum environment, and the chamber balance dynamic vacuum system becomes a vacuum system with a heat-conducting medium flowing orderly all the time. In the closed balance system, all medium steam for drying and steam evaporated from materials orderly flow into the vacuum balance chamber from the vacuum balance chamber to perform condensation heat exchange to establish balance, so that pressure balance is achieved, and balance cannot be established by vacuum pump pumping. Because the condensation phase change of the steam is generated when the steam is in contact heat exchange with the pipeline of the condensation heat exchanger and cannot be condensed before the steam is in contact with the condensation pipeline, the steam temperature of the vacuum working chamber and the steam temperature of the vacuum balance chamber are basically the same, the system can be used as an isothermal and isobaric system, and the properties of the steam in the two chambers are the same when the temperature T and the pressure P of the system are fixed. According to the inference of avogalois law, the thermal equilibrium system is a mass-balanced, pressure-balanced, heat-balanced thermal equilibrium system.

An auxiliary heat exchanger is arranged in the vacuum working chamber, and a heating medium used in the auxiliary heat exchanger can be selected in various ways according to the types and specific working conditions of the dried materials; the refrigerant in the condenser tube bundle arranged in the vacuum balance chamber communicated with the condenser tube bundle can also be selected according to specific working conditions. After the steam enters the vacuum working chamber for full heat exchange, the steam flows to the vacuum balance chamber with low pressure to exchange heat with the heat exchanger of the condenser, the steam condensation amount in unit time is equal to the steam generation amount, the dynamic pressure balance in the vacuum can be formed, and the establishment of the dynamic vacuum system with the heat-conducting medium is completed.

The utility model discloses the people changes the condenser among the prior art for the vacuum balance room, has given new technical angle and has come the effect of cognitive condensation technique again at superheated steam drying, does the means of regard it as processing waste gas and energy recuperation among the prior art promptly, and in this application, it more maintains the means as dry vacuum's developments for superheated steam drying continuous production, energy saving and emission reduction reach more excellent effect.

Drawings

FIG. 1 is a schematic diagram of a balanced dynamic vacuum system and a partial cross-sectional view of a vacuum chamber;

FIG. 2 is a cross-sectional view of a vacuum chamber b-b for drying wood;

FIG. 3 is a sectional view of a sludge drying vacuum chamber b-b

FIG. 4 is a sectional view of a dry vacuum chamber b-b of a transformer

FIG. 5 is a schematic diagram of a chamber balance dynamic vacuum system for processing liquid materials

FIG. 6 is a schematic diagram of the thermal balance and pressure balance of a dynamic vacuum system with chamber balance

Illustration of the drawings:

in fig. 1: 10 is a vacuum working chamber, 11 is a medium inlet, 12 is a steam outlet, 13 is a steam outlet valve, 14 is a flow meter, 15 is a medium inlet valve, 16 is a steam-water separator, 17 is a condensed water tank, 18 is a water tank rear valve, 19 is a water tank front valve, 20 is a vacuum balance chamber, 21 is a refrigerant inlet, 22 is a refrigerant outlet, 23 is a condensing heat exchanger, 24 is a vacuum pump valve, 25 is a vacuum pump, 26 is an electric level gauge, 27 is a drainage pump connecting valve, 28 is a liquid flow meter, 29 is a drainage pump, 31 is a heat medium inlet, 32 is a heat medium outlet, 33 is an auxiliary heat exchanger, 38 is a fan, s is a drainage trap, s1 is a drainage trap valve, and 40 is a control system.

In fig. 2: 39 is wood, 34 is an air duct clapboard, 35 is an air duct, 36 is a material trolley, and 37 is a trolley track.

In fig. 3: 39 is sludge, 34 is an air duct clapboard, 35 is an air duct, 36 is a material trolley, and 37 is a trolley track.

In fig. 4: 39 is a transformer, 34 is an air duct clapboard, 35 is an air duct, 36 is a material trolley, and 37 is a trolley track.

In fig. 5: 10. the three

vacuum working chambers

10a and 10b are respectively a primary evaporation vacuum working chamber 10, a secondary evaporation vacuum working chamber 10a and a tertiary evaporation vacuum working chamber 10 b; 20. the three vacuum balance chambers 20a and 20b are respectively a third-stage vacuum balance chamber 20, a second-stage vacuum balance chamber 20a and a first-stage vacuum balance chamber 20 b; 26. 26a and 26b are three electric level meters, 30a and 30b are three water pumps, 39a and 39b are two front valves, 41a and 41b are two rear valves, 27a and 27b are three connecting valves, and 42 is a raw liquid pump.

Detailed Description

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the present invention is described in detail below with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making more clear definitions of the protection scope of the present invention.

Chamber balanced dynamic vacuum system basic principle: the dynamic vacuum system with balanced chamber consists of a vacuum working chamber and a vacuum balance chamber, wherein the vacuum working chamber is provided with a heat exchanger for supplying heat to medium gas, the vacuum balance chamber is provided with a condensing heat exchanger, the two chambers are communicated, the vacuum pump is started to pump vacuum to required pressure, the vacuum degree can reach ultrahigh vacuum, the vacuum pump is closed, a static vacuum system is established, and the pressure P of the static vacuum system is kept constant. When a chamber balance dynamic vacuum environment is established, a steam valve connected with a vacuum working chamber is opened, medium steam enters the vacuum working chamber, the pressure p1 of the vacuum working chamber is increased, the vacuum degree is reduced, the steam flows to the vacuum balance chamber with low pressure, the condensed phase in the vacuum balance chamber is changed into water, the condensed water amount is large, the space tightness cannot be damaged due to timely discharging of the condensed water, the condensed water is stored in the balance chamber in a centralized and quantitative mode, therefore, the balance chamber has enough space to store the condensed water, the pressure p2 of the vacuum balance chamber is reduced, the vacuum degree is increased, a control system adjusts the condensing speed, the pressure p1 of the two chambers is more than or equal to p2, namely: the vacuum degree of the vacuum balance chamber is more than or equal to that of the vacuum working chamber, the two chambers reach pressure balance and have stable vacuum degree, and a dynamic vacuum with pressure balance on the basis of mass balance is formed, namely: a chamber-balanced dynamic vacuum system with a heat transfer medium.

The dynamic vacuum does not need a vacuum pump to work, and the pressure balance of the two chambers maintains the vacuum stability. The steam is changed into superheated steam through heat exchange between the air channel and the auxiliary heat exchanger, then heat is transferred to the material, moisture in the water vapor heat release material absorbs heat to generate low-temperature boiling point evaporation, the water flows to the balance chamber to be condensed and changed into water, the moisture in the material is continuously and rapidly evaporated until the humidity sensor displays the moisture content required by the material, and the whole process is controlled by the intelligent control system after the work is finished.

When the pressure of the vacuum balance chamber approaches the pressure of the vacuum working chamber, the dynamic vacuum system maintains stable balance, and P1 is not less than P2 and is more than P all the time in the working process of the system

The following describes a chamber balanced dynamic vacuum system, as shown in fig. 1, comprising a vacuum working chamber 10, a vacuum balancing chamber 20, and a control system 40. The vacuum working chamber 10 is provided with a medium inlet 11 and a steam outlet 12, and the medium inlet 11 is sequentially connected with a steam source, a gas flowmeter 14, a medium inlet valve 15 and a steam-water separator 16; the steam outlet 12 is communicated with the vacuum balance chamber 20 through a steam outlet valve 13; an auxiliary heat exchanger 33 is installed in the vacuum working chamber 10, heat medium enters the auxiliary heat exchanger 33 from a heat medium inlet 31 and flows out of the auxiliary heat exchanger 33 from a heat medium outlet 32; a fan 38 is arranged in the vacuum working chamber 10; the lower part of the vacuum working chamber 10 is provided with a condensed water tank 17, the condensed water tank 17 is communicated with the vacuum working chamber 10 through a water tank rear valve 18, a water tank front valve 19 is arranged at the water outlet of the condensed water tank 17, the bottom of the vacuum working chamber is provided with a steam trap S, namely a control valve S1, and the steam trap is only used when the working chamber is used for heat treatment of materials.

The vacuum balance chamber is composed of two vacuum balance chambers 20 with the same structure, a medium steam inlet of the former vacuum balance chamber 20 is communicated with a steam outlet 12 of the vacuum working chamber 10 through a steam outlet valve 13, a vacuum pump 25 interface of the former vacuum balance chamber 20 is communicated with a medium steam inlet of the latter vacuum balance chamber 20, and a vacuum pump 25 interface of the latter vacuum balance chamber 20 is connected with a vacuum pump 25 through a vacuum pump valve 24; the bottom parts of the two vacuum balance chambers 20 are respectively provided with an electric liquid level meter 26; a condensing heat exchanger 23 is installed in each vacuum balance chamber 20, and the refrigerant enters the condensing heat exchanger 23 through a refrigerant inlet 21 and flows out of the condensing heat exchanger 23 through a refrigerant outlet 22; the two vacuum balance chambers 20 are respectively provided with a drain pump connecting valve 27 at the bottom drain port and are connected with a drain pump 29 through a liquid flowmeter 28.

The control system 40 connects and controls the opening and closing of the valves and pumps and collects data signals for feedback flow meters and level gauges.

As shown in fig. 2, the sectional view of the wood drying vacuum chamber b-b is shown.

An auxiliary heat exchanger 33 is arranged on the inner wall surface of the vacuum working chamber 10 and is separated from a drying chamber for placing materials to be dried through an air duct partition plate 34, and heat medium enters the auxiliary heat exchanger 33 from a heat medium inlet 31 and flows out of the auxiliary heat exchanger 33 from a heat medium outlet 32; the medium inlet 11 of the vacuum working chamber 10 is communicated with the inner side of the air duct partition plate 34, the steam outlet 12 is communicated with the outer side of the air duct partition plate, and medium steam enters the air duct 35 between the auxiliary heat exchanger 33 and the air duct partition plate 34 from the medium inlet 11 of the vacuum working chamber 10 to be heated and then flows into the drying chamber to heat the materials to be dried. A skip track 37 is arranged in the vacuum working chamber 10, and after the materials to be dried are loaded into the material trolley 36, the materials are pushed into the vacuum working chamber 10 along the skip track 37.

As shown in the attached figure 3, a section view of a sludge drying vacuum working chamber b-b.

As shown in figure 4, the sectional view of the transformer drying vacuum working chamber b-b is shown.

FIG. 5 is a schematic diagram of a chamber balance dynamic vacuum system for processing liquid materials.

The dynamic vacuum system with balanced chambers is a device for evaporating and concentrating liquid materials by three-stage evaporation, and multi-stage evaporation is needed during large-scale production.

The dynamic vacuum system comprises three vacuum working chambers, namely a primary evaporation vacuum working chamber 10, a secondary evaporation vacuum working chamber 10a, a tertiary evaporation vacuum working chamber 10b and the like, wherein the vacuum working chambers are vertically arranged, three auxiliary heat exchangers 33 are respectively arranged at the lower parts in the three vacuum working chambers 10, liquid materials to be dried are injected from a medium inlet 11 of the primary evaporation vacuum working chamber 10, and the auxiliary heat exchangers 33 are directly heated to generate medium steam mixed with water vapor; the medium inlet 11 of the primary evaporation vacuum working chamber 10 is sequentially connected with the stock solution, the stock solution pump 42 and the medium inlet valve 15; the bottom liquid discharge ports of the three vacuum working chambers 10 are communicated with the medium inlet 11 through water pumps 30 and 30a and front valves 39a and 39b respectively, and the bottom liquid discharge port of the three-stage evaporation vacuum working chamber 10b is provided with a water pump 30b for discharging concentrated solution; the bottoms of the three vacuum working chambers 10 are respectively provided with electric liquid level meters 26, 26a and 26 b; the steam outlet 12 of the first-stage evaporation vacuum working chamber 10 is directly communicated with the first-stage vacuum balance chamber 20 through a steam outlet valve 13, and the second-stage evaporation vacuum working chamber 10a and the third-stage evaporation vacuum working chamber 10b are respectively communicated with the steam outlet valve 13 through back valves 41a and 41b and then communicated with the first-stage vacuum balance chamber 20;

the dynamic vacuum system comprises three vacuum balance chambers, namely a first-stage vacuum balance chamber 20, a second-stage vacuum balance chamber 20a, a third-stage vacuum balance chamber 20b and the like, and the connecting structure form is similar to that of the dynamic vacuum system in figure 2. Drain

pump connection valves

27, 27a, 27b are respectively installed at the bottom drain ports of the three vacuum balance chambers 20 and are connected to a drain pump 29 through a liquid flow meter 28.

The heat source of the auxiliary heat exchanger 33 can be steam waste heat, flue gas waste heat, solar energy, or boiler steam, or heat conducting oil from an external factory, and the heat source heats the heating medium to circularly heat the stock solution to be evaporated through the auxiliary heat exchanger 33.

The temperature of the processing liquid in the third evaporation vacuum chamber 10b is the highest, and the concentration is also the highest, so the concentrated liquid is discharged from the third evaporation vacuum chamber 10b through the bottom water pump 30 b.

The vacuum working chamber and the vacuum balance chamber are both provided with an electric liquid level meter, the bottoms of the vacuum balance chambers are connected, and both are provided with a condensed water outlet and discharge condensed water through a drainage pump 29. The condenser refrigerant outlets of the vacuum balance chambers are connected to the refrigerant outlet 22, and the refrigerant inlets are connected to the refrigerant inlet 21.

The material drying method comprises the following implementation steps: the implementation steps are as follows:

(1) a static vacuum system was constructed. Before the operation, the material is placed in the material trolley 36 and pushed into the vacuum working chamber 10 along the trolley track 37, the chamber door is closed, the steam outlet valve 13 connected with the vacuum working chamber 10 and the vacuum balance chamber 20 is opened, the vacuum pump 25 connected with the vacuum balance chamber 20 is opened to vacuumize to a required range, a static vacuum balance is established, the vacuum degree range can be high vacuum or ultrahigh vacuum as required, and the vacuum pump is closed;

(2) a balance is set up in the static vacuum system. Opening a medium inlet valve 15 connected with a vacuum working chamber 10, leading steam to pass through a steam-water separator 16, leading a control system 40 to adjust the flow rate of the steam entering the vacuum working chamber 10 to the medium steam entering amount required by drying materials according to the heat exchange amount requirement, increasing the pressure of the vacuum working chamber 10, reducing the vacuum degree, leading the steam to pass through an air duct 35, exchanging heat with an auxiliary heat exchanger 33 and absorbing heat, then transferring heat to the materials, boiling the water in the materials at low temperature and evaporating the water to form steam, mixing the steam and the medium steam to continuously flow to a vacuum balance chamber 20 and enter the air duct 35 respectively, leading the steam entering the vacuum balance chamber 20 to exchange heat with a condensing heat exchanger 23, leading a refrigerant to circularly absorb the steam heat through a refrigerant inlet 21 and a refrigerant outlet 22, condensing and changing the phase of the steam, reducing the pressure of the vacuum balance chamber, increasing the vacuum degree, leading the control system 40 to adjust the flow rate of the refrigerant, leading the pressure P2, after the pressures of the vacuum working chamber 10 and the vacuum balance chamber 20 are balanced, the dynamic vacuum system completes the dynamic vacuum pressure balance, and the dynamic vacuum system starts to run in a drying mode. In large-scale production, the heat absorbed by the refrigerant can be recovered for heat supply.

(3) And draining the balance chamber. In order to keep the vacuum volume of the vacuum balance chamber 20 basically stable and drain the condensed water in time, the control system 40 sets the water level of the magnetic plate-turning level gauge 26, after the condensed water reaches the water level, the control system 40 automatically opens the drain pump connecting valve 27 arranged on the pipeline to open the drain pump 29 to pump out the condensed water, the amount of the drained water is the amount calculated according to the value of the magnetic plate-turning level gauge 26, the flow meter 28 feeds back data to the control system 40, the control system 40 drains water as required, the drain pump connecting valve 27 is closed after draining, and the drain pump 29 automatically stops working.

(4) And draining water from the vacuum working chamber. In the system working process, some condensed water is arranged at the bottom of the vacuum working chamber 10, in order to not influence the environment of the vacuum working chamber 10, a condensed water tank 17 is arranged at the bottom of the vacuum working chamber 10, a front water tank valve 19 at the front end of the condensed water tank 17 is normally opened, the condensed water flows into the condensed water tank 17, the front water tank valve 19 is closed during drainage, a rear water tank valve 18 at the rear end is opened for drainage, and after the drainage is completed, the front water tank valve 19 is opened again by the rear water tank valve 18 after the water tank is closed.

(5) In the operation process of the vacuum system, the intelligent monitoring system 40 automatically adjusts the chamber balance dynamic vacuum system according to the feedback signals of the temperature sensor, the humidity sensor and the pressure sensor of the vacuum working chamber 10 until the drying or evaporation of the material is completed. The following are specific drying apparatus and applications of the drying method.

The first embodiment is as follows: wood drying step:

1) drying preparation: the palletized timber is placed on a skip 36 and pushed into the vacuum chamber 10 along a rail 37, and the chamber door is closed. Opening the valve 13 and the valve 24, starting the vacuum pump 25 to vacuumize to the set pressure, exhausting the indoor air, closing the valve 13 and the valve 24, and stopping the vacuum pump 25.

2) Wood preheating: opening a medium steam inlet valve 15 and an auxiliary heat exchanger 33 heat exchange system, circularly supplying heat through an inlet 31 and an outlet 32 by a heat medium, wherein the heat medium can be heat conduction oil or high-temperature high-pressure steam, controlling the medium steam pressure and the temperature of the auxiliary heat exchanger 33 by a control system 40, heating for preset time at the heating temperature of 30-100 ℃ according to the required temperature, closing the medium inlet valve 15, and finishing heating.

3) Draining: closing the medium steam inlet valve 15, opening the front water tank valve 19 and the rear water tank valve 18 to drain the condensed water and steam in the vacuum working chamber 10, so that the absolute pressure of the vacuum working chamber 10 is reduced to 0.11Mp, namely, the gauge pressure is 0.01Mp, keeping a bit of positive pressure to prevent air from entering, closing the rear water tank valve 18 and the front water tank valve 19 by the control system, and finishing the drainage.

4) Establishing a static vacuum: the control system opens the connecting valve 13 between the two chambers, the valve 24 opens the vacuum pump 25, the vacuum pumping reaches the preset pressure P, the static pressure of the vacuum working chamber 10 and the vacuum balance chamber 20 is balanced, and the valve 24 and the vacuum pump 25 are closed.

5) Building dynamic balance: the control system 40 opens the medium inlet valve 15, medium steam enters the vacuum working chamber 10 through the steam-water separator 16, and the steam flow is adjusted to the flow required by medium drying and heat exchange according to the feedback data of the gas flowmeter 14. The pressure P1 of the vacuum working chamber 10 is increased, the vacuum degree is reduced, the steam enters the vacuum balance chamber 20 for condensation phase change, the pressure P2 of the vacuum balance chamber 20 is reduced, the vacuum degree is increased, P1 is larger than or equal to P2, the control system 40 adjusts the condensation speed, P1 is larger than or equal to P2, and dynamic vacuum chamber balance is formed.

6) The wood is dried. Medium steam enters the vacuum working chamber 10, the fan 38 is started, the steam exchanges heat with the auxiliary heat exchanger 33 through the air duct 35 to absorb heat, the auxiliary heat exchanger needs to be heated slowly, the temperature is controlled to be slightly higher than the low-temperature boiling point of the water in the working chamber, the heatable steam is superheated steam in the later drying period, the heating speed influences the drying quality of the wood too fast, the medium steam transfers heat to the wood, the water in the wood reaches the low-temperature boiling point boiling in vacuum, the water is gasified into steam through phase change, the heat of the medium steam is absorbed in the gasification process of the water in the wood, the enthalpy of the medium steam is reduced, the medium steam after heat exchange is mixed with the water vapor evaporated by the wood, the humidity is increased, part of the wet steam enters the air duct 35 again to exchange heat, the superheated steam and exchange heat with the wood, the wet steam after, the condensed phase is changed into water, the water yield is calculated according to the water level of the electric level gauge 26, the data is fed back to the control system 40 by the flowmeter 28, the control system 40 automatically starts the drainage pump 29, and the drainage pump 29 automatically stops working after drainage is finished. The control system 40 automatically adjusts the chamber balance dynamic vacuum system according to feedback signals of the temperature sensor, the humidity sensor and the pressure sensor of the working chamber 10, controls the pressure P1 of the vacuum working chamber 10 and the pressure P2 of the vacuum balance chamber 20 to be stabilized at required pressure values, keeps the dynamic balance P1 ≧ P2, continuously works until the humidity of the vacuum working chamber 10 reaches the preset requirement, and finishes drying.

The wood balances the moisture. After the drying is finished, the medium inlet valve 15 is closed, the heat source of the auxiliary heat exchanger 33 is stopped, and the vacuum environment is maintained for 3 and 4 hours by natural cooling.

In the whole process, the dynamic vacuum system controls and keeps stable pressure balance on the basis of heat balance and mass balance, and the basic state of the steam heat-conducting medium in the vacuum system is stable and controllable. As the medium steam is superheated steam after secondary heating and has the dryness of 100 percent, the moisture in the wood can be continuously evaporated until the humidity sensor displays that the wood has the required moisture content, and the work is finished.

Example two: and (3) slurry drying:

1) drying preparation: the slurry to be dried is loaded into the vessel, lifted by the support in layers and placed on the skip 36, pushed into the working chamber 10 along the rail 37, and the chamber door is closed. Opening the valve 13 and the valve 24, starting the vacuum pump 25 to vacuumize to a set pressure, exhausting the indoor air, closing the valve 13 and the valve 24, and stopping the vacuum pump 25

2) Preheating and anaerobic sterilization: opening a medium steam inlet valve 15 and an auxiliary heat exchanger 33 heat exchange system, circularly supplying heat through an inlet 31 and an outlet 32 by a heat medium, wherein the heat medium can be heat conduction oil or high-temperature high-pressure steam for heat transfer, controlling the medium steam pressure and the temperature of the auxiliary heat exchanger 33 by a control system 40, heating for preset time at the heating temperature of 50-70 ℃ according to the required temperature, closing the medium inlet valve 15, and ending heating, wherein the pressure of the vacuum working chamber 10 is positive pressure at the moment.

3) Water and steam discharging: closing the medium steam inlet valve 15, opening the front water tank valve 19 and the rear water tank valve 18 to drain the condensed water and steam in the vacuum working chamber 10, so that the absolute pressure of the vacuum working chamber 10 is reduced to 0.11Mp, namely, the gauge pressure is 0.01Mp, keeping a point of positive pressure to prevent air from entering, closing the rear water tank valve 18 and the front water tank valve 19 by the control system, and finishing the drainage and steam drainage.

5) Building dynamic balance: the control system 40 opens the medium inlet valve 15, medium steam enters the vacuum working chamber 10 through the steam-water separator 16, and the steam flow is adjusted to the flow required by medium drying and heat exchange according to the feedback data of the gas flowmeter 14. The pressure P1 of the vacuum working chamber 10 is increased, the vacuum degree is reduced, steam enters the vacuum balance chamber 20 for condensation phase change, the pressure P2 of the vacuum balance chamber 20 is reduced, the vacuum degree is increased, P1 is not less than P2 and is more than P, the control system 40 adjusts the steam flux and the condensation speed between the two chambers, the pressure P2 of the vacuum balance chamber 20 and the pressure P1 of the vacuum working chamber 10 keep P1 not less than P2, and dynamic vacuum chamber balance is formed.

6) Drying the sludge. Medium steam enters the vacuum working chamber 10, the fan 38 is started, the steam exchanges heat with the auxiliary heat exchanger 33 through the air channel 35 to absorb heat, the medium steam is heated to be superheated steam, the medium steam transfers heat to sludge, moisture in the sludge reaches low-temperature boiling point boiling in vacuum, the moisture is gasified in a phase change manner to be water vapor, the moisture in the sludge absorbs the heat of the medium steam in the gasification process, the medium steam after heat exchange is mixed with the water vapor evaporated by the sludge, the humidity is increased, part of wet steam enters the air channel 35 again to exchange heat to be superheated steam and exchange heat with the sludge, the wet steam after heat exchange enters the vacuum balancing chamber 20 through the steam outlet 12 of the vacuum working chamber 10 to exchange heat with the condensation heat exchanger 23, the condensation phase is changed into water, and the

The water amount is calculated, data are fed back to the control system 40 through the flow meter 28, the control system 40 automatically starts the drainage pump 29 to drain water to the sewage pool, further sewage treatment is carried out as required, and the drainage pump 29 automatically stops working after drainage is finished. The control system 40 automatically adjusts and controls the pressure P1 of the vacuum working chamber 10 and the pressure P2 of the vacuum balance chamber 20 to be stabilized at a required pressure value according to feedback signals of the temperature sensor, the humidity sensor and the pressure sensor of the working chamber 10, and keeps the dynamic balance P1 ≧ P2, the dynamic vacuum system continuously works until the humidity of the vacuum working chamber 10 reaches a preset requirement and is dried to a block with 10% of water, and due to the drying shrinkage effect of the block sludge, the sludge is separated from the container, is easy to take out and is dried.

7) High-temperature heat treatment of the sludge drying block: after drying is finished, the valve 13 is closed, the large steam valve 15 is opened to ensure that the pressure of the working chamber is positive pressure, the temperature is increased to 150-200 ℃, and the high-temperature heat treatment is carried out on the sludge blocks for 3-5 hours. Under the high-temperature heat treatment of the superheated steam, organic substances, bacteria and microorganisms contained in the sludge are decomposed or carbonized at high temperature, and the sludge is beneficial to landfill, incineration or other purposes.

Example three: drying the transformer:

1) drying preparation: when the transformer is placed on the trolley 36, it is pushed into the working chamber 10 along the rail 37, and the chamber door is closed. Opening the valve 13 and the valve 24, starting the vacuum pump 25 to vacuumize to a set pressure, exhausting the indoor air, closing the valve 13 and the valve 24, and stopping the vacuum pump 25

2) Establishing a static vacuum: the control system opens the connecting valve 13 between the two chambers, the valve 24 opens the vacuum pump 25, the vacuum pumping reaches the preset pressure P, the static pressure of the vacuum working chamber 10 and the vacuum balance chamber 20 is balanced, and the valve 24 and the vacuum pump 25 are closed.

3) Building dynamic balance: the control system 40 opens the medium inlet valve 15, medium steam enters the vacuum working chamber 10 through the steam-water separator 16, and the steam flow is adjusted to the flow required by medium drying and heat exchange according to the feedback data of the gas flowmeter 14. The pressure P1 of the vacuum working chamber 10 is increased, the vacuum degree is reduced, steam enters the vacuum balance chamber 20 for condensation phase change, the pressure P2 of the vacuum balance chamber 20 is reduced, the vacuum degree is increased, P1 is not less than P2 and is more than P, the control system 40 adjusts the steam flux and the condensation speed between the two chambers, the pressure P2 of the vacuum balance chamber 20 and the pressure P1 of the vacuum working chamber 10 keep P1 not less than P2, and dynamic vacuum chamber balance is formed.

4) Drying the insulation of the transformer, medium steam enters the vacuum working chamber 10, a fan 38 is started, the steam exchanges heat with the auxiliary heat exchanger 33 through an air duct 35 to absorb heat, the medium steam is heated to be superheated steam, the temperature of the medium steam is not more than 105 ℃, the medium steam transfers heat to the insulation material of the transformer, moisture in the insulation material reaches low-temperature boiling point in vacuum to be gasified, the heat of the medium steam is absorbed in the moisture gasification process, enthalpy drop of the medium steam occurs, the medium steam after heat exchange is mixed with the water vapor evaporated by the insulation material, humidity is increased, part of the wet steam enters the air duct 35 again to exchange heat to be superheated steam and exchange heat with the insulation material, the wet steam after heat exchange with the insulation material enters the vacuum balance chamber 20 through a steam outlet 12 of the vacuum working chamber 10 to exchange heat with a condensation heat exchanger 23, the condensation phase is changed into water, data are fed back to the control system 40 through the flow meter 28, the control system 40 automatically starts the drainage pump 29, and the drainage pump 29 automatically stops working after drainage is finished. The control system 40 automatically adjusts the chamber balance dynamic vacuum system according to feedback signals of the temperature sensor, the humidity sensor and the pressure sensor of the working chamber 10, controls the pressure P1 of the vacuum working chamber 10 and the pressure P2 of the vacuum balance chamber 20 to be stabilized at required pressure values, keeps the dynamic balance P1 ≧ P2, and continuously works until the humidity of the vacuum working chamber 10 reaches the preset requirement, and the drying is carried out until the moisture content is less than 0.5%, and the drying is finished. The moisture content of the insulating material of the transformer cannot exceed 0.5%, otherwise, the coil is easily punctured, the service life is influenced, a large transformer comprises hundreds of kilograms of insulating material, a large amount of moisture is contained in the large transformer, the large transformer is extremely difficult to dry, a dynamic vacuum system utilizes superheated steam as a heat-conducting medium, energy is saved, efficiency is high, and the dynamic vacuum system is a very good scheme for drying the insulating material of the transformer.

Example four: examples of evaporative concentration of liquid Material

The evaporation and concentration of the liquid material are applied to seawater desalination, sewage concentration, metallurgy and chemical intermediates and the concentration treatment of mixed liquid needing crystallization treatment.

The implementation steps are as follows:

(1) charging and establishing a static vacuum. The control system 40 opens the medium inlet valve 15 to add the stock solution to the preset height of the electric liquid level meter 26, opens the two rear valves 41a and 41b and the steam outlet valve 13, closes the two front valves 39a and 39b and the three connecting

valves

27, 27a and 27b, opens the vacuum pump valve 24, starts the vacuum pump 25 to vacuumize to the preset required pressure P, stops the vacuum pumping by the control system, and simultaneously closes the vacuum pump valve 24 and the two front valves 39a and 39 b. The control system 40 starts the auxiliary heat exchanger 33 and the condensation heat exchanger 23, the auxiliary heat exchanger 33 heats the temperature of the raw liquid in the primary evaporation vacuum working chamber 10, the pressure range of the primary evaporation vacuum working chamber 10 is set, the moisture in the raw liquid is boiled and evaporated, the pressure P1 of the primary evaporation vacuum working chamber 10 is increased, the vacuum degree is reduced, the steam rapidly enters the primary vacuum balance chamber 20b, the secondary vacuum balance chamber 20a, the tertiary vacuum balance chamber 20 and the condensation heat exchanger 23 in sequence to exchange heat and condense into water, the pressure P2 of the three vacuum balance chambers is reduced, the vacuum degree is increased, the condensation speed is controlled, and the vacuum degree is kept stable; when the control system 40 monitors that the temperature of the stock solution of the primary evaporation vacuum working chamber 10 is higher than the low-temperature boiling point by 20 ℃, the front valve 39a is opened, the water pump 30 is started, hot water in the primary evaporation vacuum working chamber 10 is pumped to the secondary evaporation vacuum working chamber 10a, when the water level of the electric liquid level meter 16 is reduced to a set water supplementing water level, the water pump 30 stops pumping water, the stock solution pump 42 is started, and the stock solution is supplemented to the primary evaporation vacuum working chamber 10 to a set high water level; continuously heating the stock solution to a temperature higher than the low-temperature boiling point by 20 ℃, and repeatedly adding water into the secondary evaporation vacuum working chamber 10a until the water level of the secondary evaporation vacuum working chamber 10a is added to a set height; when the temperature of the first-stage evaporation vacuum working chamber 10 is monitored to be higher than the low-temperature boiling point by 20 ℃, the front valve 39b and the water pump 30a are opened to replenish water to the third-stage evaporation vacuum working chamber 10b, the first-stage evaporation vacuum working chamber 10 replenishes water to the second-stage evaporation vacuum working chamber 10a, the raw liquid pump 42 replenishes water to the first-stage evaporation vacuum working chamber 10, the control system 40 automatically monitors that the water level of any vacuum working chamber falls to a replenishing water level, the water replenishing to the next-stage vacuum working chamber is stopped, meanwhile, the upper-stage water pump starts replenishing water to a set high level, the dynamic vacuum system multistage evaporation device with the water levels of the three vacuum working chambers balanced.

(2) And (5) building balance. Setting the temperature range of the auxiliary heater to be not lower than 70 ℃, the low-temperature boiling point to be less than 20 ℃, namely not lower than, corresponding to the required pressure of 50 ℃, 0.012Mp, namely the vacuum degree of-0.088 Mp, after the control system finishes charging, detecting the temperature and the pressure of the vacuum system, when the vacuum degree is less than-0.088 Mp, opening a vacuum pump valve 24, starting a vacuum pump 25 to perform vacuum compensation till the vacuum degree is not less than-0.088 Mp, stopping the vacuum pump 25, closing the vacuum pump valve 24, continuously evaporating the vacuum working chamber stock solution at the low-temperature boiling point, leading steam to enter a vacuum balance chamber for condensation phase change, adjusting the steam flux and the condensation speed of a steam outlet valve 13 by a control system 40, ensuring the balance of the whole dynamic vacuum system to be stable, ensuring that the pressure of the vacuum working chamber and the P1 and the P2 of the vacuum balance chamber are basically stable, keeping the P1 not, the chamber balance dynamic vacuum system starts working by multi-stage evaporation.

(3) The material evaporates. In the dynamic vacuum system operation process, one-level evaporation vacuum studio 10, second grade evaporation vacuum studio 10a, drainage water level and moisturizing water level are all set for to tertiary evaporation vacuum studio 10b, tertiary evaporation vacuum studio 10b still is equipped with row concentrate and finishes the water level, when arbitrary vacuum studio water level reachs the moisturizing water level, start the row's concentrate to the row's concentrate that the liquid level appearance was set for from tertiary evaporation vacuum studio 10b bottom water pump 30b earlier and finish the water level, and simultaneously, backward moisturizing step by step, promptly: the second-stage evaporation vacuum working chamber 10a supplies water to the third-stage evaporation vacuum working chamber 10b, the first-stage evaporation vacuum working chamber 10 supplies water to the second-stage evaporation vacuum working chamber 10a, and the raw liquid pump 42 supplies water to the first-stage evaporation vacuum working chamber 10; meanwhile, any condensed water level of the three-stage vacuum balance chamber 20, the two-stage vacuum balance chamber 20a and the one-stage vacuum balance chamber 20b reaches the set height of the electric level gauge 26, the control system automatically opens the corresponding connecting valves 27, 27a and 27b, the drainage pump 29 is started to drain water, and the pump is stopped and closed.

(4) The control system 40 monitors the temperature and pressure changes during operation, and timely adjusts and controls the temperature and pressure changes until the operation is finished.

Claims

1. Dynamic vacuum system of room equilibrium for evaporative concentration of liquid material, including vacuum studio (10), auxiliary heat exchanger (33), condensation heat exchanger (23) and vacuum balance room (20), its characterized in that:

the vacuum working chamber (10) is vertically arranged and is used for containing liquid materials, a medium inlet (11) and a steam outlet (12) are formed in the vacuum working chamber (10), an auxiliary heat exchanger (33) is installed at the lower portion in the vacuum working chamber (10), liquid materials to be dried are injected from the medium inlet (11) of the vacuum working chamber (10) and are directly heated by the auxiliary heat exchanger (33) to generate steam, and the vacuum working chamber (10) is communicated with a vacuum balance chamber (20) through the steam outlet (12) and a steam outlet valve (13);

the vacuum balance chamber (20) is provided with a condensing heat exchanger (23) for condensing steam flowing from the vacuum working chamber (10) and is connected with a vacuum pump (25), and the bottom of the vacuum balance chamber (20) is provided with a water outlet;

the condensing heat exchanger (23) evaporates the medium mixed with the water vapor flowing from the vacuum working chamber (10) in the vacuum balancing chamber (20) to change the water vapor condensation phase into condensed water, and the condensed water is gathered at the bottom of the vacuum balancing chamber (20) and is discharged through a water outlet.

2. The chamber balanced dynamic vacuum system of claim 1, wherein: the vacuum balance chambers (20) are multistage balance chambers, namely two or more vacuum balance chambers (20) are connected in series to form the multistage balance chambers, the vacuum pump (25) interface of the previous vacuum balance chamber (20) is communicated with the medium steam inlet of the next vacuum balance chamber (20), and the vacuum pump interface of the last vacuum balance chamber (20) is connected with the vacuum pump (25).

3. The chamber balanced dynamic vacuum system of claim 1, wherein: the vacuum working chambers (10) are multi-stage evaporation chambers, namely two or more vacuum working chambers (10) are connected in series to form the multi-stage evaporation chambers, and a liquid outlet at the bottom of each vacuum working chamber (10) is communicated with the medium inlet (11) through a water pump between the vacuum working chambers (10).

4. The chamber balanced dynamic vacuum system of claim 1, wherein: the magnetic turning plate liquid level meter (26) is installed at the bottom of the vacuum balance chamber (20), a gas flowmeter (14) and a medium inlet valve (15) are sequentially installed at a medium inlet (11) of the vacuum working chamber (10), a vacuum pump valve (24) is installed between the vacuum balance chamber (20) and a vacuum pump (25), a drainage pump connecting valve (27), a liquid flowmeter (28) and a drainage pump (29) are installed at a drainage port at the bottom of the vacuum balance chamber (20), and the valves and the pumps are controlled to be switched on and off through a control system (40).

5. The chamber balanced dynamic vacuum system of claim 1, wherein: an electric liquid level gauge (16) is also included for detecting the water level at the bottom of the vacuum working chamber (10).