JPH0381069B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention dehumidifies and dries air for processing substances that must be dried at low temperatures, such as foods, pharmaceuticals, powder and granule agents, sludge, etc. The present invention relates to a heat pump device for use in a heat pump.

[Conventional technology]

Conventionally, dehumidification when drying substances that must be dried at low temperatures, such as foods, pharmaceuticals, powder and granule agents, sludge, etc., has generally been done by spraying a solution such as lithium chloride or ethylene glycol and dehumidifying by exchanging heat with the air. Air is created, and the solution, which has absorbed moisture and is diluted, is heated and concentrated by a concentrator, and then cooled by air cooling. In addition, a separately provided refrigerator is used as a pre-cooling chamber for the material to be dried.

[Problem that the invention seeks to solve]

The conventional technology requires fan power, pump power, etc. from a cleaning tower, and an extra concentrating device for heating and concentrating. In addition, the solution mixes with the circulating air and scatters, so the solution must be constantly replenished, and the solution is a consumable item. Furthermore, the heat required for heating and concentration is 80%, considering the boiler efficiency.
The thermal efficiency is as follows. Therefore, the maintenance and management of the device is very troublesome and imposes a heavy economic burden. In addition, there were also disadvantages in that lithium chloride, ethylene glycol, etc. mixed in the air adhered to the dried material, and there was also the problem of spoilage. Furthermore, since a boiler must be provided for heating and a refrigerator must be provided for cooling, this poses problems in terms of energy conservation and increases equipment costs. The present invention aims to solve these drawbacks, and instead of using lithium chloride or ethylene glycol for dehumidification, it adopts a freezing type dehumidification method to create low-temperature dehumidified dry air and blow or circulate it. At the same time, the purpose is to achieve energy saving and eliminate the drawbacks of the conventional technology by heating using a heat pump.

[Means for solving problems]

As a means for solving the above problems, the heat pump device of the present invention includes a drying chamber using dry air, an air chamber for producing the dry air, and at least two sets of reverse Carnot cycles as heating and cooling means in the air chamber. The drying room and the air chamber are connected by a circuit for introducing dry air and a circuit for circulating hygroscopic air, and
Inside the air chamber, an endothermic heat exchanger and an exothermic heat exchanger of a secondary reverse Carnot cycle are installed at positions closest to the air inlet side and the air outlet side of the air chamber, respectively, and a primary reverse Carnot cycle heat exchanger is installed in the air chamber. an endothermic heat exchanger and an exothermic heat exchanger,
It is provided inside each of the endothermic heat exchanger and the exothermic heat exchanger of the secondary reverse Carnot cycle.

[Effect]

Inside the air chamber, the circulating air or outside air that has absorbed moisture is first cooled and dehumidified using two sets of heat pump devices, then heated using the heat pump devices to adjust the temperature to an appropriate temperature, and then introduced into the drying room. .

By arranging the endothermic heat exchanger and exothermic heat exchanger of the primary reverse Carnot cycle in a specific manner, the compression ratio of both cycles can be made small, and the coefficient of performance for heating and cooling can be reduced. are both large.

[Embodiments of the invention]

One embodiment of the present invention will be explained with reference to FIG. This embodiment can be used in combination with the so-called "air circulation closed cycle system" and the "outside air (fresh air) intake type open cycle system."

Reference numeral 1 denotes a drying chamber, in which raw materials 6 such as foods, pharmaceuticals, powder and granule drugs, sludge, etc., to be dried are introduced into a pre-cooling chamber 2 of the drying chamber 1 by a conveyor, and are crushed into homogeneous particles by a uniform pulverizer 3. It is fed onto a net conveyor 4, dried while moving in a drying chamber 1, and delivered as a finished product 7 such as food, medicine, powder or granule, sludge, etc. Inside the drying chamber 1, there are upper and lower partition plates 14,
15 into a number of sections 16, each section 1
Air flows vertically inside the chamber.

The drying air is introduced into the drying chamber 1 as follows. First, cold air at a temperature of 5 to 7° C. is introduced into the pre-cooling chamber 2 by the blower 9 through the inflow pipes 11a and 11b. Low-temperature dry air of 30 to 40°C/6 g/Kg is dried by being divided into three sections 16 through inflow pipes 13a and 13b by a blower 8, and then sent to three other sections 16 from an inflow pipe 13c. After drying, the air flows out from the circulation pipe 13d, is removed by a filter 70, and flows into the air chamber 17 again from the circulating air duct 18 by the blower 8a.

Next, the air chamber 17 will be explained. Inside the air chamber 17, in the direction of air flow, there are a pre-cooler 21, a first cooler 22, a second cooler 23,
Eliminator 24, intermediate heater 54, reheater 2
5. A hot water heater 26 is provided.
35 from circulating air duct 18 to air chamber 17
℃/13.5g/Kg of moisture-absorbing air flows in, is precooled to 19℃ by the precooler 21, and is cooled to 15.5℃ by the first cooler 22.
to condense moisture, and then to the second cooler 2.
3, the water is further condensed, and the water is removed in an eliminator 24. 28 is a drain trap. Next, the dehumidified air is heated in the intermediate heater 54 and the reheater 25, and then further heated by the hot water heater 26.
The dry air will be 40-50℃/6g/Kg. This dry air passes through the inflow pipes 13a and 13b and returns to the drying chamber 1.
be introduced within.

Next, the exchange of heat from or to the air flowing through the air chamber 17 will be explained.

The precooler 21 and the reheater 25 are the pump 3
A closed cycle is formed in which a refrigerant (ethylene glycol, brine, etc.) is circulated by the reheater 25, and the refrigerant is cooled to about 11.5°C by 6.5°C cold air in the reheater 25, and then cooled to a precooler by the pump 30. 21, the hygroscopic air at 35°C is precooled, becomes a refrigerant liquid at around 30°C, returns to the reheater 25, and the air at 6.5°C passes through the intermediate heater 54 to about 25°C.
Raise the temperature to

H is a secondary reverse Carnot cycle, that is, a heat pump cycle on the high stage side, in which the refrigerant is compressed by a compressor 31 and condensed by a hot water heater (condenser) 32, and the liquid refrigerant passes through a liquid pipe 62 and is dissipated as an intercooler. The liquid refrigerant flows into the container (condenser) 35 and is cooled through the liquid pipe 64.
19 flows into the first cooler 22 through the main expansion valve 33, evaporates, and flows out by the pre-cooler 21.
After cooling the air at ℃ to 15.5℃, compressor 3
1 is inhaled. R is a primary reverse Carnot cycle on the lower stage, that is, a refrigeration cycle, in which the refrigerant compressed by the compressor 34 is introduced from the gas pipe 60 to the intermediate heater 54 via the three-way valve 47c, and the air from the second cooler 23 is introduced into the intermediate heater 54. It is heated, cooled and partially condensed, flows into the radiator 35 through the gas pipe 53, then passes through the gas pipe 61, passes through the evaporation pressure regulating valve 37, and enters the compressor 31 together with the refrigerant from the first cooler 22. Inhaled. The liquid refrigerant flowing into the radiator 35 from the gas pipe 53 passes through the valve 49 and joins the refrigerant in the liquid pipe 62 .
Further, the liquid refrigerant branched from the liquid pipe 64 flows into the heat exchanger 30 through the liquid pipe 52 and is cooled, then flows into the second cooler 23 through the expansion valve 36, evaporates, and flows out from the first cooler 22. ℃ more air
Cool to 6.5°C. The evaporated refrigerant flows into the heat exchanger 30 through the evaporation pressure regulating valve 38, provides cold heat, and is then sucked into the compressor 34 again.

The evaporation temperature of the first cooler 22 on the introduction side of the humid air is around 10°C, and the evaporation temperature of the second cooler 23 is 0°C or slightly higher. This is because if the temperature is below 0°C, frost will adhere to the fin coil of the heat exchanger, causing a problem.

The heating of the air at the outlet of the air chamber 17 takes place as follows. The hot water heated to about 42° C.±2° C. by the hot water heater 32 of the heat pump cycle H flows into the hot water heater 26 via the hot water pipe 45 and the hot water pipe 45a by the circulation pump 46. 47
The hot water supply electric three-way valve adjusts the flow rate of hot water. The hot water radiated by the hot water heater 26 flows through the reflux pipe 4.
4, 44a and returns to the hot water heater 32. The hot water branched from the hot water supply electric three-way valve 47 is sent to the radiator 48
Excess heat from the heat pump is released outside the system, and the temperature of the dry air is maintained at an appropriate temperature.

In the above embodiment, air circulates through the drying chamber 1 and the air chamber 17 in a closed cycle.
When the humidity of the outside air is lower than the humidity of the hygroscopic air coming out of the drying room 1, the outside air is sucked directly into the air chamber 17 from the fresh air intake port 50 by the blower 8a, and the hygroscopic air is discharged from the hygroscopic air outlet 51, and the outside air is An intake type open cycle system can also be used.
However, in general, when taking in and discharging outside air repeatedly, there is a high risk that bacteria and dust may be mixed in, and there is also the problem of oxidizing the product, so care must be taken.

FIG. 2 shows a second embodiment which is a partial modification of the embodiment shown in FIG. In the first embodiment, the high-pressure refrigerant discharged from the compressor 31 of the heat pump cycle H is hot water (lower in temperature) that is returned from the hot water heater 26 at the outlet of the air chamber 17 via the return pipe 44a. However, in the second embodiment, the high-pressure refrigerant is directly supplied to the refrigerant condenser 26a via gas pipes 45, 45a. It differs from the first embodiment in that it is configured to flow into the water and be cooled and condensed, but the other configurations are the same, so a description thereof will be omitted.

FIG. 3 shows a third embodiment which is a partial modification of the first embodiment (FIG. 1). Portions with the same reference numerals as those in FIG. 1 have the same names and structures, and their functions are also the same, so their explanations will be omitted. This embodiment differs from the first embodiment in that a means for auxiliary cooling of a radiator (condenser) 35 as an intercooler with outside air or well water is provided. That is, the radiator 35 is connected to an outside air radiator (cooling tower) 41 via cooling water pipes 39, 40 and a pump 42, and the well water 5
6 is connected to the cooling water pipe 40 via the pump 55 and the well water inflow pipe 57, and the well water outflow pipe 58 is connected to the cooling water pipe 3.
9, respectively, so that it can be switched to either outside air or well water. Therefore, when the intermediate heater 54 is not used,
The three-way valve 47c is switched to allow the refrigerant discharged from the compressor 34 to flow directly into the radiator 35 as an intercooler, and the cooling system of the outside air radiator 41 or the well water 56 is operated to cool it. I can do it. In addition, in this embodiment, by appropriately adjusting the valves of the liquid pipes 62 and 65, a part of the refrigerant liquid condensed in the hot water heater 32 is allowed to flow through the liquid pipes 65 and 66 without flowing into the radiator 35. This embodiment is also different from the first embodiment in that the refrigerant liquid flows into the first cooler 22 and only the other part of the refrigerant liquid can flow into the second cooler 23 via the liquid pipe 62, the heat radiation pipe 35, and the liquid pipes 67, 63. It's different.

FIG. 4 shows a fourth embodiment that is a partially modified version of the third embodiment.
This is an example. In this implementation, the heat pump cycle H on the high-stage side and the refrigeration cycle R on the low-stage side are completely separated from each other on the flow of refrigerant, and the radiator 35a and the intermediate heater 54 are connected to the refrigeration cycle R. This embodiment differs from the third embodiment in that it is incorporated into the system in parallel. According to this embodiment, different refrigerants can be used in the heat pump cycle H and the refrigeration cycle R, respectively. The rest of the configuration is the same as the third embodiment, so a description thereof will be omitted.

〔Effect of the invention〕

The present invention does not use lithium chloride or ethylene glycol for dehumidification, but uses a refrigeration type dehumidification method to create low-temperature dry air and blow or circulate it, increasing the dehumidification efficiency of the heat pump and saving energy. At the same time, when using a refrigerator for cold air drying, the raw material can also be cooled. Then, the humidified circulating air or outside air is cooled and dehumidified using a heat pump, and then the air is heated to the air outlet condition in the drying chamber by heating by the heat pump, reducing the relative humidity and achieving energy-saving drying. can.

[Brief explanation of drawings]

1 to 4 are system diagrams of different embodiments of the present invention. 1...Drying chamber, 13a, 13b, 13c...Inflow pipe as a circuit for introducing dry air from the air chamber into the drying chamber, 13d...Recirculation pipe as a circuit for circulating hygroscopic air from the drying chamber to the air chamber. 17... Air chamber, 18... Circulating air duct as a circuit for circulating hygroscopic air from the drying room to the air chamber, 22... First cooler as an endothermic heat exchanger, 23... As an endothermic heat exchanger a second cooler, 26... a hot water heater as a heat exchanger for generating heat, and 54... an intermediate heater as a heat exchanger for generating heat.

Claims (1)

[Scope of Claims] 1. A drying chamber using dry air, an air chamber for producing dry air, a circuit for introducing the dry air from the air chamber into the drying chamber, and a circuit for circulating hygroscopic air from the drying chamber to the air chamber. , at least two sets of reverse Carnot cycles, comprising an endothermic heat exchanger and an exothermic heat exchanger of the reverse Carnot cycle in the air chamber, and a secondary reverse Carnot cycle endothermic heat exchanger in the air chamber. The heat exchanger for heat generation of the secondary reverse Carnot cycle is installed closest to the air outlet side of the air chamber, and the heat exchanger for heat absorption of the primary reverse Carnot cycle and the heat exchanger for heat generation of the primary reverse Carnot cycle are installed closest to the air outlet side of the air chamber. A heat pump device for dehumidifying and drying air, characterized in that an exchanger is installed inside each of the corresponding endothermic heat exchanger and exothermic heat exchanger of the secondary reverse Carnot cycle. 2. The heat pump device for air dehumidification and drying according to claim 1, wherein the heat exchanger for heat generation of the secondary reverse Carnot cycle is a hot water heater. 3. The heat pump device for air dehumidification and drying according to claim 1, wherein the heat exchanger for heat generation of the secondary reverse Carnot cycle is a refrigerant condenser. 4 Claims 1 to 3, characterized in that the endothermic heat exchanger of the primary reverse Carnot cycle and the secondary reverse Carnot cycle is a refrigerant evaporator.
A heat pump device for dehumidifying and drying air according to any one of paragraphs. 5 Claim 1, characterized in that the exothermic heat exchanger of the primary reverse Carnot cycle is an intermediate heater that utilizes the heat of refrigerant gas discharged from the compressor.
A heat pump device for dehumidifying and drying air according to any one of items 1 to 4. 6 Claims 1 to 5, characterized in that a radiator as an intercooler is provided between the intermediate heater of the primary reverse Carnot cycle and the suction side of the compressor of the secondary reverse Carnot cycle. A heat pump device for dehumidifying and drying air according to any one of the above. 7. Any one of claims 1, 3 to 5, characterized in that an intermediate heater and a radiator are provided in parallel between the compressor and evaporator of the primary reverse Carnot cycle. A heat pump device for dehumidifying and drying the air as described. 8. Any one of claims 1 to 7, characterized in that the secondary reverse Carnot cycle is a high-stage cycle and the primary reverse Carnot cycle is a low-stage cycle, which is configured as a two-stage or binary compressor. A heat pump device for dehumidifying and drying air as described in . 9. According to any one of claims 1 to 8, wherein a heat exchanger is provided on the air inlet side and the air outlet side of the air chamber, respectively, to form a closed circulation path through which a heat medium flows. A heat pump device for dehumidifying and drying the air as described. 10. The air filter according to any one of claims 1 to 9, characterized in that a circuit for circulating the hygroscopic air from the drying chamber to the air chamber is provided with an outside air inlet and a hygroscopic air outlet. Heat pump device for dehumidifying and drying. 11. Claims 1 to 10 characterized in that the cold air on the outlet side of the heat exchanger for endothermic absorption of the primary reverse Carnot cycle in the air chamber is introduced into the front room or pre-cooling room of the drying room.
2. A heat pump device for air dehumidification and drying according to any one of paragraphs. 12 The refrigerant of the primary reverse Carnot cycle is R12.
The heat pump device for dehumidifying and drying air according to claim 7, wherein the refrigerant of the second reverse Carnot cycle is R114.