CN201138106Y - A liquid nitrogen heat exchange device for liquid nitrogen-assisted freeze-drying equipment - Google Patents

Abstract

The utility model relates to a liquid nitrogen heat exchange device for liquid nitrogen auxiliary freeze-drying equipment. Nitrogen gasification tube, the lower end of the liquid nitrogen gasification tube is connected to the liquid nitrogen inlet and nitrogen outlet in the middle of the cylinder, at least two U-shaped heat conduction circulation oil pipes are arranged in the middle of the liquid nitrogen vaporization pipe, and the top of the U-shaped heat conduction circulation oil pipe passes through the cylinder cover One end is connected to the heat transfer circulating oil inlet, and the other end is connected to the heat transfer circulating oil outlet. The middle of the liquid nitrogen gasification pipe and the heat transfer circulating oil pipe is fixed by a baffle plate. The heat transfer oil temperature probes are respectively installed on the heat transfer circulating oil inlet and the heat transfer circulating oil outlet. The nitrogen temperature probe and the upper liquid level interface are set on the upper side of the cylinder, and the safety valve and the lower liquid level interface are installed at the upper end of the liquid nitrogen inlet and liquid nitrogen outlet, and the nitrogen outlet and nitrogen outlet temperature probes are respectively installed at the bottom of the cylinder . The utility model has the advantage that the liquid nitrogen can safely exchange heat with the circulating heat-conducting oil.

Description

A liquid nitrogen heat exchange device for liquid nitrogen-assisted freeze-drying equipment

technical field

The utility model relates to a liquid nitrogen heat exchange device for liquid nitrogen auxiliary freeze-drying equipment, in particular to a liquid nitrogen from a storage tank that is vaporized through the heat exchange device and circulated with a liquid nitrogen vacuum freeze dryer. The invention relates to a heat exchanger for conducting heat exchange with heat transfer oil, which belongs to the technical field of heat exchangers.

Background technique

Vacuum freeze dryer is a machine for freeze-drying water-containing substances by using the principle of freeze-drying to cool and freeze water-containing substances into a solid state, and then sublimate water vapor directly from the solid state under vacuum conditions.

At present, vacuum freeze dryers are mainly divided into two categories in terms of refrigeration methods: 1. Refrigeration using refrigerant Freon compressors; 2. Refrigeration using liquid nitrogen.

At present, the use of liquid nitrogen refrigeration has the following disadvantages:

1. The temperature of liquid nitrogen is extremely low. Under a certain pressure, the temperature of liquid nitrogen is -196°C. Such a low temperature cannot directly exchange heat with the circulating heat transfer oil of the vacuum freeze dryer, otherwise the circulating heat transfer oil will freeze Phenomenon;

2. Liquid nitrogen has been widely used in other fields, but it has just started to be used in the field of pharmaceutical machinery such as liquid nitrogen vacuum freeze dryer. At present, there is no mature and efficient liquid nitrogen heat exchange device.

Contents of the invention

The purpose of the utility model is to provide a liquid nitrogen heat exchange device for liquid nitrogen assisted freeze-drying equipment that can safely exchange heat with circulating heat transfer oil.

In order to achieve the above objectives, the technical solution of this utility model is to provide a liquid nitrogen heat exchange device for liquid nitrogen assisted freeze-drying equipment, which is characterized in that it consists of a liquid nitrogen gasification tube, a heat conduction circulation oil tube, a baffle plate and a cylinder , there is a ring of liquid nitrogen gasification tubes on the inner wall of the cylinder, the lower end of the liquid nitrogen gasification tubes is connected with the liquid nitrogen inlet and nitrogen outlet in the middle of the cylinder body, and at least two U-shaped heat conduction circulation oil pipes are arranged in the middle of the liquid nitrogen gasification tubes, U-shaped The top end of the heat conduction circulation oil pipe passes through the cylinder cover, and one end is connected to the heat conduction circulation oil inlet, and the other end is connected to the heat conduction circulation oil outlet. On the oil inlet and the heat conduction circulating oil outlet, the nitrogen temperature probe and the upper liquid level interface are set on the upper side of the cylinder, and the safety valve and the lower liquid level interface are installed on the upper end of the liquid nitrogen inlet and liquid nitrogen outlet, respectively. Equipped with nitrogen outlet and nitrogen outlet temperature probe.

The utility model gasifies the liquid nitrogen from the storage tank and conducts heat exchange with the heat-conducting circulating oil, turns the liquid nitrogen into low-temperature nitrogen, and performs heat exchange between the low-temperature nitrogen and the heat-conducting circulating oil, avoids the phenomenon that the liquid nitrogen freezes the circulating heat-conducting oil, and fully The latent and sensible heat of liquid nitrogen is used to exchange heat with circulating heat transfer oil efficiently and safely.

The utility model has the advantage that the liquid nitrogen can safely exchange heat with the circulating heat-conducting oil.

Description of drawings

Fig. 1 is a schematic structural diagram of a liquid nitrogen heat exchange device of a liquid nitrogen-assisted freeze-drying equipment;

Fig. 2 is a sectional view of a liquid nitrogen heat exchange device A-A of a liquid nitrogen assisted freeze-drying equipment.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described further.

Example

As shown in Figures 1 and 2, it is a schematic structural diagram of a liquid nitrogen heat exchange device for a liquid nitrogen-assisted freeze-drying equipment. The liquid nitrogen heat exchange device for a liquid nitrogen-assisted freeze-drying equipment consists of a liquid nitrogen gasification tube 1. The heat conduction circulation oil pipe 2, the baffle plate 3 and the cylinder body 4 are composed of 12 liquid nitrogen gasification tubes 1 in a circle on the inner wall of the cylinder body 4, the lower end of the liquid nitrogen gasification tube 1 and the liquid nitrogen inlet 10 in the middle of the cylinder body 4 and The nitrogen outlet 11 is connected, and 10 U-shaped heat-conducting circulating oil pipes 2 are installed between the liquid nitrogen gasification pipes 1. The top of the U-shaped heat-conducting circulating oil pipe 2 passes through the cylinder body 4. One end of the cover is connected to the heat-conducting circulating oil inlet 5, and the other end is connected to the heat-conducting circulating oil. The outlet 6 is connected, the middle of the liquid nitrogen gasification pipe 1 and the heat conduction circulation oil pipe 2 is fixed by the baffle plate 3, the heat conduction oil temperature probe 7 is respectively installed on the heat conduction circulation oil inlet 5 and the heat conduction circulation oil outlet 6, the nitrogen temperature probe and the upper liquid level The interface 8 is installed on one side of the upper end of the cylinder 4, a safety valve and a lower liquid level interface 9 are installed on the upper end of the liquid nitrogen inlet 10 and the liquid nitrogen outlet 11, and a nitrogen outlet 12 and a nitrogen outlet temperature probe 13 are respectively provided at the bottom of the cylinder 4 .

During operation, liquid nitrogen enters the liquid nitrogen inlet 10 from the storage tank and enters the liquid nitrogen gasification tube 1 in the heat exchanger. The liquid nitrogen gasifies due to pressure drop during the process of rising in the liquid nitrogen gasification tube 1. From liquid state to gaseous state, because the volume ratio of nitrogen gas-liquid two-phase is 800:1, so this process will absorb a lot of heat, this heat is provided by circulating heat transfer oil, when the circulating heat transfer oil enters from the heat transfer circulating oil inlet 5 to In the heat exchanger, it flows down along one end of the heat conduction circulation oil pipe 2, bends 180° when it reaches the bottom, then flows upward, and flows out from the heat conduction circulation oil outlet 6. During this process, the gasified nitrogen reaches the top and then flows Downward flow, through a lot of baffles 3 in the process of downward flow, to increase the flow path of nitrogen gas, so as to perform heat exchange more efficiently, and the heat of the heat conduction circulating oil is absorbed by the nitrogen gas formed by liquid nitrogen gas during the flow process, and the temperature Reduce, and nitrogen is discharged from nitrogen outlet 12 at last, completes this heat exchange process.

From the above working principle, liquid nitrogen is not in direct contact with the heat transfer circulating oil, but the nitrogen gas after liquid nitrogen vaporization is in contact with the heat transfer circulating oil tube, which avoids the freezing of the heat transfer circulating oil. Phenomena to refrigerate, using volume expansion to absorb a large amount of heat, and using temperature probes everywhere to collect temperature signals, and output signals through the upper and lower liquid level differences to reasonably control the amount of liquid nitrogen entering, making full and efficient use of liquid nitrogen .

Claims (1)

1. the liquid nitrogen heat-exchanger rig of a liquid nitrogen auxiliary cooling freeze-drier, it is characterized in that, by liquid nitrogen gasification pipe (1), heat conduction circulating pipe (2), deflection plate (3) and cylindrical shell (4) are formed, be provided with a circle liquid nitrogen gasification pipe (1) at cylindrical shell (4) inwall, liquid nitrogen gasification pipe (1) lower end is connected with nitrogen outlet (11) with the liquid nitrogen import (10) at cylindrical shell (4) middle part, in the middle of liquid nitrogen gasification pipe (1), be provided with at least two U-shaped heat conduction circulating pipes (2), U-shaped heat conduction circulating pipe (2) top is passed cylindrical shell (4) Gai Yiduan and is connected with heat conduction recycle oil import (5), the other end is connected with heat conduction recycle oil outlet (6), fixing in the middle of liquid nitrogen gasification pipe (1) and the heat conduction circulating pipe (2) by deflection plate (3), conduction oil temp probe (7) is located at respectively in heat conduction recycle oil import (5) and the heat conduction recycle oil outlet (6), nitrogen temperature is popped one's head in and is gone up liquid level interface (8) and be located at cylindrical shell (4) upper end one side, be provided with safety valve in the upper end of liquid nitrogen import (10) and liquid nitrogen outlet (11) and reach liquid level interface (9) down, be respectively equipped with nitrogen outlet (12) and nitrogen outlet temp probe (13) in cylindrical shell (4) bottom.

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