CN117731807A

CN117731807A - Heating or sterilizing treatment device for powder

Info

Publication number: CN117731807A
Application number: CN202311766698.3A
Authority: CN
Inventors: 平田利雄
Original assignee: Fujiwara Techno Art Co Ltd
Current assignee: Fujiwara Techno Art Co Ltd
Priority date: 2023-08-03
Filing date: 2023-12-21
Publication date: 2024-03-22
Also published as: JP7371995B1

Abstract

The invention provides a powder particle heating or sterilizing treatment device with a heating part which can prevent powder particles from adhering, has high hardness, is not easy to wear and resists heat deformation. The device is provided with: the powder particle sterilizing device comprises a powder particle (10) supply mechanism (11), a powder particle input part (12) for inputting the powder particle, a condensing gas supply part (13), a heating part (14) for heating the powder particle, and a pressure reducing part (15) for opening a mixture of the powder particle and the condensing gas to a space lower than the heating part, wherein the heating part is made of metal, a coating layer is plated on the inner surface, the contact angle between the surface of the coating layer and water is more than 90 degrees, the surface roughness is less than or equal to 1.6 mu m, the hardness is more than or equal to HV140, after the powder particle is input into the condensing gas, the mixture flows in the heating part at a flow rate of less than or equal to 200 m/s under a pressurized condition, heat of the condensing gas is transferred to the powder particle, condensation is generated on the surface of the powder particle, and the pressure reducing part is opened to the space, so that the powder particle is heated or sterilized.

Description

Heating or sterilizing treatment device for powder

Technical Field

The present invention relates to a heating and sterilizing apparatus for powder and granular material using a condensable gas, and more particularly, to a heating and sterilizing apparatus for powder and granular material capable of preventing powder and granular material from adhering to an inner surface of a heating portion and abrasion of the heating portion.

Background

Conventionally, there is known a heat treatment apparatus for sterilizing a powder or granule by heating the powder or granule by being put into a flow of a condensable gas (for example, patent document 1 below). In such a heat treatment apparatus, the powder and particle flows together with the condensable gas in the heating section. In the heating section, the powder and particle is heated by the condensable gas, and condensation occurs on the surface of the powder and particle due to a temperature difference between the condensable gas and the powder and particle. If the amount of condensation is large, the powder particles easily adhere to the inner surface of the heating portion. In particular, a raw material (such as capsicum) having a large amount of sugar or oil and a raw material (such as a thickener) having high adhesiveness due to water absorption are likely to adhere to each other.

If the powder particles adhere to the inner surface of the heating portion, the powder particles adhere to each other and agglomerate or burn. If the caking of the adhering matter or the burnt portion is peeled off and mixed into the airflow, the caking and the burnt portion become causes of deterioration in quality and mixing of foreign matters. Further, if the adhesion to the inner surface of the heating portion is increased, the surface area of the heating portion becomes small, and the heating treatment condition changes. If the adhesion is further increased, the heating portion is blocked, and the operation is interrupted.

Therefore, a device for preventing adhesion of powder particles has been proposed. Patent document 2 below proposes a heat treatment apparatus that prevents adhesion of powder particles by forming the inner surface of a heating portion with a non-adhesive material. In addition, in this document, it is proposed that the non-adhesive material is preferably a fluororesin.

Prior art literature

Patent literature

Patent document 1: japanese patent No. 4499184

Patent document 2: japanese patent No. 6232242

Disclosure of Invention

Technical problem to be solved by the invention

However, the non-adhesive material used in the heat treatment apparatus described in patent document 2 is generally a resin, as represented by a fluororesin, and has a technical problem of low hardness and easy abrasion. Such abrasion causes foreign matter to be mixed in. Further, if wear increases, the surface area in the heating portion becomes large, resulting in a decrease in flow rate and internal pressure. In addition, if wear increases, the life of the device decreases. Further, the resin is easily thermally deformed, and the heating temperature in the heating portion needs to be controlled to be within a predetermined temperature.

The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a powder heating or sterilizing apparatus including a heating portion which prevents adhesion of powder, has high hardness, is less likely to wear, and is also resistant to thermal deformation.

Solution to the above technical problems

In order to achieve the above object, a powder heating or sterilizing apparatus according to the present invention includes: a supply mechanism for supplying the powder; a powder input unit for inputting the powder from the supply mechanism; a condensable gas supply unit for blowing a condensable gas into the powder; a heating unit configured to heat the powder or granule by using the condensable gas; and a pressure reducing unit that opens a mixture of the powder and granular material and the condensable gas into a space lower than the heating unit, wherein the heating unit is made of metal, a plating layer is plated on an inner surface of the heating unit, a contact angle between a surface of the plating layer and water is 90 degrees or more, a surface roughness is at most 1.6 μm, and a hardness is at least HV140, and after the powder and granular material is put into the condensable gas, the mixture flows under a pressurized condition into the heating unit at a flow rate of 200 m/sec or less while heat of the condensable gas is transferred to the powder and granular material by a temperature difference between the powder and granular material, condensation is generated on the surface of the powder and granular material, and the powder and granular material is heated or sterilized by opening the pressure reducing unit into the space lower than the heating unit.

According to the powder and granular material heating or sterilizing apparatus of the present invention, adhesion of the powder and granular material due to coagulation can be prevented by setting the contact angle between the surface of the plating layer, which is the inner surface of the heating portion, and water to 90 degrees or more and the surface roughness to ra1.6 μm or less. In addition, the hardness of the surface of the plating layer is set to HV140 or more, so that the plating layer has high hardness and is not easily worn. Thus, not only can foreign matter mixing in due to worn materials be prevented, but also expansion of the surface area of the inner surface due to wear can be prevented, and reduction of flow rate and internal pressure can be prevented, thereby enabling the lifetime of the device to be prolonged. Further, the heating portion is formed by plating the inner surface of the metal with a plating layer, and thus the heating temperature can be increased. This structure is simple in structure and high in strength, and therefore can achieve weight reduction due to thickness reduction.

In the powder and granular material heating or sterilizing apparatus according to the present invention, the following structures are preferable. The inner surface of the pressure reducing portion is coated with a plating layer, preferably, the contact angle between the surface of the plating layer and water is more than 90 degrees, the surface roughness is less than Ra1.6mu m, and the hardness is more than HV 140. According to this configuration, the same effect as that of the heating section can be obtained even in the pressure reducing section.

The pressure reducing portion is preferably constituted by a tubule. According to this configuration, the pressure reducing portion can be realized with a simple configuration.

The pressure reducing portion is preferably constituted by a rotary valve. According to this configuration, by changing the rotational speed of the rotary valve, the time for heating the powder or granular material under the pressurized condition can be easily changed.

The heating portion is preferably grounded. According to this configuration, the powder particles due to static electricity can be prevented from adhering to the inner surface of the heating portion. This prevents deterioration of quality and contamination of foreign matter due to caking, scorching, etc., and also prevents reduction of the surface area of the inner surface of the heating portion due to adhesion, thereby preventing an increase in flow rate and internal pressure, and facilitating cleaning.

Effects of the invention

As described above, according to the present invention, adhesion of the powder particles due to coagulation can be prevented by setting the contact angle between the surface of the plating layer, which is the inner surface of the heating portion, and water to 90 degrees or more and the surface roughness to ra1.6 μm or less. In addition, the hardness of the surface of the plating layer is set to HV140 or more, so that the plating layer has high hardness and is not easily worn. Thus, not only can foreign matter mixing in due to worn materials be prevented, but also expansion of the surface area of the inner surface due to wear can be prevented, and reduction of flow rate and internal pressure can be prevented, thereby enabling the lifetime of the device to be prolonged. Further, the heating portion is formed by plating the inner surface of the metal with a plating layer, and thus the heating temperature can be increased. This structure is simple in structure and high in strength, and therefore can achieve weight reduction due to thickness reduction.

Drawings

Fig. 1 is a schematic configuration diagram of a heating or sterilizing apparatus according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view taken along line AA of fig. 1.

Fig. 3 is a side view illustrating a contact angle with water.

Fig. 4 is a side view showing a state where a contact angle θ with water is greater than 90 degrees in an embodiment of the present invention.

Fig. 5 is a schematic configuration diagram of a heating or sterilizing apparatus according to another embodiment of the present invention.

Fig. 6 is a cross-sectional view showing another embodiment (rotary valve) of the pressure reducing portion of the present invention.

Detailed Description

An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a schematic configuration diagram of a heating and sterilizing apparatus 1 (hereinafter referred to as "apparatus 1") according to an embodiment of the present invention. The object of the heating or sterilizing treatment of the apparatus 1 is the powder or granule 10. The powder or granule 10 is not particularly limited, and examples thereof include cereal flour such as wheat flour and rice flour, bran, seaweed powder, fish meal, vegetable powder, vegetable chip powder, tea powder, spice powder such as pepper, powder of various additives, powder of pharmaceuticals, powder of cosmetics, and powder of various feeds.

The present invention prevents the powder particle 10 from adhering to the inner surface of the heating part 14, and makes the heating part 14 hard and not easy to wear and also resistant to heat deformation. Therefore, the effect of the present invention can be particularly exhibited when a powder or granule that easily adheres, a raw material containing a large amount of sugar or oil, such as capsicum, or a raw material that absorbs water and has high adhesiveness, such as a thickener, is used as a heating target. Through the heating or sterilization process performed by the apparatus 1, it is possible to perform heating or sterilization treatment and prevent the propagation of harmful organisms such as microorganisms or pests.

In fig. 1, the apparatus 1 is mainly composed of a supply mechanism 11, a powder and particle charging unit 12, a condensable gas supply unit 13, a heating unit 14, and a pressure reducing unit 15. In the present embodiment, a hopper is used as the supply mechanism 11, a screw feeder is used as the powder and granular material input section 12, a heating pipe is used as the heating section 14, and a tubule is used as the decompression section 15. The condensable gas supply unit 13 is constituted by a condensable gas supply source 131 and a condensable gas supply path 132.

The powder and particle charging section 12 and the heating section 14 are connected via a raw material supply passage 16. A cooling pipe 17 is connected to the downstream side of the pressure reducing portion 15, and a cyclone 18 is connected to the downstream side of the cooling pipe 17. The cooling duct 17 is connected to the blower 19 via a blower passage 191.

The following describes a heating or sterilizing process of the powder or granular material 10 by the apparatus 1 in the sequence of steps with reference to fig. 1. In fig. 1, a powder or granular material 10 is filled in a supply mechanism 11. The powder 10 from the supply mechanism 11 is fed into the powder feeding unit 12. The powder 10 is transported in the powder input section 12 and supplied to the raw material supply passage 16. The powder or granule 10 having passed through the raw material supply passage 16 flows into the heating section 14.

At the inlet 141 of the heating section 14, a mixture of the condensable gas supplied from the condensable gas supply passage 132 and the powder or granular material 10 supplied from the raw material supply passage 16 is produced. The condensable gas is, for example, water vapor, and may be either saturated water vapor or superheated water vapor, or may be vapor of various solvents. The mixture flows to the pressure reducing portion 15. In the present embodiment, the heating unit 14 is configured such that the mixture flows at a flow rate of 200 m/sec or less under pressurized conditions.

In the heating section 14 and the pressure reducing section 15, the powder or granule 10 is heated or sterilized by the condensable gas. Specifically, due to the temperature difference between the powder and granular material 10 and the condensable gas, heat of the condensable gas is transferred to the powder and granular material, condensation occurs on the surface of the powder and granular material, and the powder and granular material 10 is heated or sterilized by opening the pressure reducing portion 15 to a space lower than the pressure increasing portion 14.

The powder or granule 10 subjected to the heating or sterilization treatment is cooled in the cooling pipe 17. The non-condensable gas from the blower 19 is supplied into the cooling pipe 17 through the blower passage 191. The non-condensable gas is, for example, air, oxygen, nitrogen, or carbon dioxide, and is a gas which does not condense even when cooled. In the cooling pipe 17, the mixed gas of the condensable gas and the powder or granular material 10 is cooled by the non-condensable gas from the blower 19, and is supplied to the cyclone 18. This can reduce the temperature of the powder or granule 10 to a predetermined temperature before being supplied to the cyclone 18. The condensable gas and the powder 10 are separated in the cyclone 18. The condensable gas is exhausted through the exhaust passage 181, and the powder or granule 10 separated from the condensable gas is recovered through the recovery passage 182.

Although the heating or sterilizing process of the powder or granular material 10 by the apparatus 1 has been described above, in the present embodiment, a configuration for preventing the powder or granular material 10 from adhering to the inner surface of the heating portion 14 is adopted, and the following description will be given. After the powder 10 is put into the condensable gas in the heating unit 14, heat is transferred to the powder 10 due to a temperature difference between the powder 10 and the condensable gas, and condensation is generated on the surface of the powder 10, thereby heating the powder 10 in a short time. On the other hand, if coagulated, the powder or granule 10 easily adheres to the inner surface of the heating portion 14.

As described above, various problems occur if the powder or granule 10 adheres to the inner surface of the heating portion 14, and therefore, patent document 2 proposes to prevent adhesion of the powder or granule by forming the inner surface of the heating portion 14 with a non-adhesive material. However, since the non-adhesive material is generally a resin, has low hardness, is easily worn, and is easily thermally deformed, a new problem arises, and the above-described matters are described.

The present inventors have derived a basic structure in which a plating layer is plated on the inner surface of a metal heating portion 14 to achieve the object of the heating portion 14, and the heating portion 14 is capable of preventing the adhesion of the powder or granular material 10, has high hardness, is not easily worn, and is also resistant to thermal deformation. Fig. 2 shows a cross-sectional view of the heating portion 14, which corresponds to the cross-sectional view taken along line AA in fig. 1. The heating part 14 is coated with a coating 142 on the inner surface of the metal tube 141.

Further, in order to achieve the above object more reliably, the present inventors have derived a specific constitution in which the contact angle of the surface of the plating layer 142 with water is 90 degrees or more, the surface roughness is ra1.6 μm or less, and the hardness is HV140 or more.

The contact angle with water is a contact angle defined by the still drop method of JIS (Japanese Industrial Specification, the same applies hereinafter) R3257:1999. Fig. 3 is a side view illustrating a contact angle with water. The contact angle with water is an angle θ between a tangent line drawn from a point (point a) where the test piece 20, the water droplet 21, and the air meet along the curved surface of the water droplet 21 and the surface of the test piece 20.

The surface roughness Ra is an arithmetic average roughness specified by JIS B601:2013. The hardness HV is a Vickers hardness defined by JIS Z2244-1:2020.

According to the configuration of the heating portion 14 of the present embodiment of the invention, the adhesion of the powder particles due to the coagulation can be prevented by setting the contact angle between the surface of the plating layer 142, which is the inner surface of the heating portion 14, and water to 90 degrees or more and the surface roughness to ra1.6 μm or less. Fig. 4 shows the water droplets 21 on the plating layer 142. In the state of fig. 4, the contact angle θ with water is greater than 90 degrees, and the separability or water repellency of the water droplet 21 becomes high. From the viewpoint of further improving the separability and the water repellency, the contact angle θ with water is more preferably 100 degrees or more.

Further, the hardness of the surface of the plating layer 142 is set to HV140 or more, whereby the hardness is high and abrasion is not easy. This can prevent foreign matter from being mixed in by worn materials, and can prevent the surface area of the inner surface from being enlarged by wear, and can prevent the reduction of the flow rate and the internal pressure, thereby prolonging the life of the device 1.

Further, the heating portion 14 is formed by plating the inner surface of the metal pipe 141 with the plating layer 142, and thus the heating temperature can be increased. This structure is simple in structure and high in strength, and therefore can achieve weight reduction due to thickness reduction.

The type of the plating layer 142 is not limited as long as the plating layer 142 has a contact angle with water of 90 degrees or more, a surface roughness of ra1.6 μm or less, and a hardness of HV140 or more. On the other hand, PTFE (fluororesin, hereinafter the same) has a very low hardness, and it is impossible to secure a hardness of HV140 or more (see comparative example 2 below).

With respect to comparative examples 1, 2 and example 1, contact angles, surface roughness and hardness are shown in table 1. In table 1, the contact angle, surface roughness and hardness are shown in parentheses as target values.

[ Table 1 ]

In comparative example 1, the entire cross section of the heating portion was made of stainless steel, and the target value of the hardness and the target value of the surface roughness could be achieved, but the target value of the contact angle could not be achieved. Comparative example 2 shows that the entire cross section of the heating portion was PTFE, and the target values of the contact angle and the surface roughness were achieved, but the target values of the hardness were not achieved. Comparative example 2 was too soft to evaluate hardness by vickers hardness, but clearly was a hardness significantly lower than the target value.

Example 1 a metal substrate was coated with a coating layer containing fluororesin particles, and the contact angle, surface roughness and hardness were all at the target values. The content of the fluororesin particles is arbitrary, and the plating layer which can achieve all target values can be selected from general-purpose products.

Here, as described above, the apparatus 1 is set such that the mixed gas of the condensable gas and the powder or granular material 10 flows at a flow rate of 200 m/sec or less. If the flow rate is greater than 200 m/sec, the flow of the powder or granule 10 becomes faster, and the powder or granule 10 is less likely to adhere to the heating portion 14, and the necessity of adhesion prevention measures is reduced. That is, this embodiment is a configuration that effectively exerts the effect of preventing the adhesion of the powder or granular material 10. This can suppress the length of the heating section 14 for securing the retention time of the powder or granular material 10, and can prevent the device 1 from being enlarged.

Fig. 5 is a schematic configuration diagram of a heating and sterilizing apparatus 1 '(hereinafter referred to as "apparatus 1'") according to another embodiment of the present invention. The same reference numerals are given to the same components as those of fig. 1, and the description thereof will be omitted. In fig. 1, the heating portion 14 is arranged in the horizontal direction, but in fig. 5, the heating portion 14 is arranged in the vertical direction. Even in this configuration, if the configuration in which the inner surface of the heating portion 14 is coated with the plating layer 142 is adopted, the following heating portion 14 can be realized in the same manner as the apparatus 1 of fig. 1: to prevent the adhesion of the powder or granule 10, and to prevent abrasion and thermal deformation even when the hardness is high.

In the apparatus 1 shown in fig. 1 and the apparatus 1' shown in fig. 5, the heating portion 14 is preferably grounded (earth). The apparatus 1 shown in fig. 1 has a ground line 143 attached to the heating section 14. The grounding is not limited to the heating portion 14, as long as the heating portion 14 can be grounded. The device 1' shown in fig. 5 has a ground wire 183 attached to the cyclone 18. With these configurations, the adhesion of the powder particles due to static electricity to the inner surface of the heating portion 14 can be prevented. This prevents deterioration of quality and contamination of foreign matter due to caking, scorching, etc., and also prevents reduction of the surface area of the inner surface of the heating portion 14 due to adhesion, thereby preventing an increase in flow rate and internal pressure, and facilitating cleaning.

While the configuration in which the inner surface of the heating portion 14 is plated with the one-layer plating layer 142 has been described above, in fig. 1 and 5, the inner surface of the pressure reducing portion 15 may be plated with the one-layer plating layer. In this configuration, as in the case of the heating portion 14, the contact angle between the surface of the plating layer and water is 90 degrees or more, the surface roughness is ra1.6 μm or less, and the hardness is HV140 or more. According to this configuration, even in the pressure reducing portion 15, the effect of preventing the adhesion of the powder or granular material 10, being hard to wear, and also being resistant to thermal deformation can be obtained in the same manner as the heating portion 14.

In fig. 1 and 5, the pressure reducing portion 15 uses a thin tube, but a rotary valve may be used instead of the thin tube. The pressure reducing portion 15' shown in fig. 6 uses a rotary valve as the pressure reducing portion. The rotary valve of the pressure reducing section 15' is connected to the heating section 14, and is composed of a supply port 151 of the powder or granular material 10, a discharge port 152 of the powder or granular material 10, a housing 153, and a rotor 155 that forms a plurality of recesses 154 in the housing 153 and rotates in the housing 153.

In this configuration, the powder or granular material 10 supplied to the supply port 151 is supplied to the recess 154 of the opening, is transferred to the discharge port 152 with rotation of the rotor 155, and falls from the recess 154 of the opening to the discharge port 152. By changing the rotational speed of the rotor 155, the time for heating the powder or granular material 10 under pressurized conditions can be easily changed.

The inner surface of the housing 153 forming the inner surface of the rotary valve may also be coated with a coating 142 on the surface of the rotor 155. In this configuration, as in the case of the heating portion 14, the contact angle between the surface of the plating layer and water is 90 degrees or more, the surface roughness is ra1.6 μm or less, and the hardness is HV140 or more. According to this configuration, the effects of preventing the adhesion of the powder or granular material 10, having high hardness, being less likely to wear, and being resistant to thermal deformation can be obtained in the same manner as the heating portion 14 even in the case 153 and the rotor 155.

Examples

Hereinafter, the present invention will be described more specifically with reference to examples. The device configuration of the embodiment is the same as the device 1 shown in fig. 1. As shown in fig. 2, the cross-sectional structure of the heating portion 14 is a structure in which the inner surface of a metal pipe 141 (stainless steel pipe in this embodiment) is plated with a plating layer 142 (embodiment 1 of table 1 in this embodiment). The pressure reducing portion 15 is also coated with a coating on the inner surface of the stainless steel pipe in the same manner as the heating portion 14.

The experimental conditions were as follows:

the inside diameter of the heating section 14 at the start of the experiment: 30.0mm

The inner diameter of the pressure reducing portion 15 at the start of the experiment: 15.0mm

Powder 10: wheat flour, chilli

Water vapor pressure at the start of the experiment: 0.40MPa

The treatment time is as follows: 1 hour

After the operation, the inside of the heating unit 14 was checked, and as a result, neither the wheat flour nor the pepper were adhered, burned, nor clogged. For comparison, it was confirmed by experiments using comparative examples that the configuration of the heating section 14 was the same as that of the example except that the pressure reducing section 15 was constituted by only a stainless steel pipe (no plating layer) having an inner diameter of 30.0mm and by only a stainless steel pipe (no plating layer) having an inner diameter of 15.0 mm. In the comparative example, the wheat flour was treated after 5 minutes and the pepper was gradually reduced after 3 minutes (discharge amount), and the local mixing of the burnt portions was started. In either case, after the 2 minutes, the heating portion 14 was completely blocked. The inside of the heating section 14 was confirmed, and as a result, the raw material was stuck to the stainless steel surface and burned, and the inside of the tube was clogged. By this comparative experiment, the adhesion preventing effect of the powder or granular material 10 of the present invention was confirmed.

The experiment using wheat flour of the above example was continued with a total treatment time of 1600 hours. During this period, the stop operation, the cleaning device, and the re-operation are repeated. The water vapor pressure during the operation was not changed, and when the inner diameters of the heating portion 14 and the pressure reducing portion 15 were measured after 1600 hours of operation, the heating portion was 30.0mm, and the pressure reducing portion was 15.0mm, which was unchanged from the case where the experiment was started. For comparison, it was confirmed by experiments using comparative examples that the configuration of the heating section 14 was the same as that of the example except that the heating section 14 was composed of a fluororesin tube having an inner diameter of 30.0mm and a stainless steel tube reinforced with a fluororesin tube from the outside, and the pressure reducing section 15 was composed of a fluororesin tube having an inner diameter of 15.0mm and a stainless steel tube reinforced with a fluororesin tube from the outside. In the comparative example, although the flow rate of the supplied water vapor was constant, the water vapor pressure during operation began to gradually decrease after 200 hours, and decreased to 0.31MPa when 1600 hours had elapsed. When the inner diameters of the heating portion 14 and the pressure reducing portion 15 were measured after 1600 hours of operation, the heating portion 14 was 30.1mm, and the pressure reducing portion 15 was 16.5mm, which was enlarged as compared with the start of the experiment. By this comparative experiment, the abrasion preventing effect of the heating portion 14 and the pressure reducing portion 15 of the present invention was confirmed.

The embodiments and examples of the present invention have been described above, but these are merely examples and may be modified as appropriate. For example, the apparatus 1 and the apparatus 1' may be provided with a heating unit 14 for heating the powder or granular material 10 with a condensable gas, and the shape and size of the heating unit 14 are arbitrary, and the arrangement is not particularly limited.

Description of the reference numerals

1. 1' heating or sterilizing treatment device

11 supply mechanism

12 powder input part

13 condensing gas supply part

14 heating part

142 coating

143 ground wire (ground)

15 pressure reducing part (tubule)

15' pressure reducing part (Rotary valve)

183 ground (ground).

Claims

1. A powder heating or sterilizing apparatus is provided with:

a supply mechanism for supplying the powder;

a powder input unit for inputting the powder from the supply mechanism;

a condensable gas supply unit for blowing a condensable gas into the powder;

a heating unit configured to heat the powder or granule by using the condensable gas; and

a pressure reducing section for opening a mixture of the powder and granular material and the condensable gas into a space lower than the heating section,

the heating part is made of metal,

a plating layer is plated on the inner surface of the heating part,

the contact angle between the surface of the plating layer and water is more than 90 degrees, the surface roughness is less than Ra1.6mu m, the hardness is more than HV140,

after the powder and particle is put into the condensable gas, the mixture flows under pressure in the heating section at a flow rate of 200 m/s or less, heat of the condensable gas is transferred to the powder and particle by a temperature difference between the powder and particle and the condensable gas, condensation is generated on the surface of the powder and particle, and the pressure reducing section opens into a space having a lower pressure than the heating section, whereby the powder and particle is heated or sterilized.

2. A powder heating or sterilizing apparatus according to claim 1, wherein,

and a plating layer is plated on the inner surface of the pressure reducing part, the contact angle between the surface of the plating layer and water is more than 90 degrees, the surface roughness is less than Ra1.6mu m, and the hardness is more than HV 140.

3. A powder heating or sterilizing apparatus according to claim 1, wherein,

the pressure reducing portion is formed of a tubule.

4. A powder heating or sterilizing apparatus according to claim 1, wherein,

the pressure reducing portion is constituted by a rotary valve.

5. A heating or sterilizing apparatus for powder or granular material according to any one of claims 1 to 4,

the heating part is grounded.