JP6435130B2 - Pressureless exhaust steam re-feed type heating system - Google Patents

Description

  The present invention relates to a non-pressure exhaust steam resupply type for reusing exhaust steam discharged in a heating system using non-pressure steam that is directly vaporized, steamed, heated and sterilized on an object to be processed under atmospheric pressure. It relates to a heating system.

  Normally, an atmospheric pressure heating apparatus that performs steaming, heating, sterilization, etc. with steam under no pressure, such as a steaming chamber, a heating chamber, or a sterilization chamber that is open to the atmosphere, is provided with an opening or an inlet / outlet. The process is performed at a temperature of about 100 ° C while discharging steam, but the steam discharged from the heating chamber may be separated into two phases of gas and liquid, and only warm liquid water may be reused. Are released into the atmosphere without being reused.

  Such release of steam into the atmosphere has a risk of deteriorating the surrounding environment due to waste heat. On the other hand, even if the steam discharged from the heating chamber is reused, if a screw compressor is used as a steam compressor for recompressing the steam, the power is excessive and the operation cost is high because the device is large. It is expensive and lacks practicality. Furthermore, simply pressurizing the vapor to be released with a vapor compressor and raising the temperature does not result in insufficient moisture due to superheated vaporization or exhausting the air contained in the vapor. Difficult to use.

  For this reason, exhaust steam discharged from the heating chamber is collected and pressurized, and the exhaust steam is reused without being superheated by discharging the air contained in the steam and adjusting the water content. It is desirable to develop a pressureless exhaust steam refeeding type heating system that can be used.

JP2013-74879A

  The present invention collects and pressurizes the exhaust steam discharged from the heating chamber, and recycles the exhaust steam without superheated steam by discharging non-condensable air contained in the steam and adjusting the moisture content. A pressureless exhaust steam re-feeding type heating system that can be used is provided.

As a result of investigations by the present inventors in order to solve the above problems, a steam introduction path for introducing steam supplied from the boiler into the heating chamber, a heating chamber for heating the contained object to be treated with steam, and , in a heating system and a vapor recovery path for recovering exhaust steam discharged from the heating chamber, the vapor recovery path roots blower, installed separator and automatic air vent then, while pressing the collected waste steam It has been found that non-condensable air other than steam and condensed moisture can be removed and introduced into the steam introduction path, and the exhaust steam can be efficiently resupplied to the heating chamber, thereby completing the present invention. .

That is, the present invention provides a steam introduction path for introducing steam supplied from a boiler into a heating chamber, a heating chamber for heating a contained object to be processed with non-pressure steam, and a non-pressure discharged from the heating chamber. and a vapor recovery path for recovering exhaust steam, a Roots blower to the vapor recovery path, established the separator and automatic air vent valve, as well as the pressure of the recovered waste steam was condensed and non-condensible air other than steam A pressureless exhaust steam resupply type heating system is characterized in that exhaust steam is resupplied to a heating chamber by removing moisture and introducing it into a steam introduction path.

  Furthermore, the present invention is a pressureless exhaust steam refeeding type heating system characterized in that water is injected into a casing incorporating a root rotor of a roots blower, and the recovered exhaust steam is introduced into the steam introduction path as saturated steam.

  Furthermore, the present invention is a pressureless exhaust steam refeeding type heating system characterized in that a roots rotor incorporated in a roots blower is made of austenitic spheroidal graphite cast iron.

  Furthermore, the present invention installs a pressure sensor in the steam recovery path, adjusts the rotation speed of the roots rotor built in the roots blower according to the pressure of the exhaust steam in the path, and introduces the exhaust steam whose pressure is adjusted to the steam introduction path. This is a pressureless exhaust steam refeeding type heating system.

  Furthermore, the present invention provides a pressure sensor in the steam recovery path, adjusts the rotational speed of the roots rotor built in the roots blower and the amount of water injected into the casing containing the roots rotor in accordance with the pressure of the exhaust steam in the path, This is a non-pressure exhaust steam re-feeding type heating system characterized in that exhaust steam with adjusted water content is introduced into a steam introduction path.

The present invention also provides a steam introduction path for introducing steam supplied from the boiler into the heating chamber, a heating chamber for heating the contained object to be processed with non-pressure steam, and a non-pressure discharged from the heating chamber. and a vapor recovery path for recovering exhaust steam, a Roots blower to the vapor recovery path, established the separator and automatic air vent valve, as well as the pressure of the recovered waste steam was condensed and non-condensible air other than steam This is a pressureless exhaust steam refeeding heating method wherein exhaust steam is resupplied to the heating chamber by removing moisture and introducing it into the steam introduction path.

  Furthermore, the present invention is a pressureless exhaust steam refeeding heating method characterized by injecting water into a casing containing a roots rotor of a roots blower and introducing the recovered exhaust steam into a steam introduction path as saturated steam.

  Furthermore, the present invention is a pressureless exhaust steam refeeding type heating method characterized in that a roots rotor incorporated in a roots blower is made of austenitic spheroidal graphite cast iron.

  Furthermore, the present invention installs a pressure sensor in the steam recovery path, adjusts the rotation speed of the roots rotor built in the roots blower according to the pressure of the exhaust steam in the path, and introduces the exhaust steam whose pressure is adjusted to the steam introduction path. This is a pressureless exhaust steam refeeding type heating method.

  Furthermore, the present invention provides a pressure sensor in the steam recovery path, adjusts the rotational speed of the roots rotor built in the roots blower and the amount of water injected into the casing containing the roots rotor in accordance with the pressure of the exhaust steam in the path, And a non-pressure exhaust steam re-feed type heating method, wherein exhaust steam with adjusted water content is introduced into a steam introduction path.

  According to the pressureless exhaust steam resupply type heating system of the present invention (or the pressureless exhaust steam resupply heating method), the exhaust steam discharged from the heating chamber is collected and introduced into the steam supply path while being pressurized by the roots blower. Thus, the exhaust steam can be efficiently resupplied to the heating chamber.

  By installing a pressure sensor in the steam recovery path and adjusting the rotational speed of the roots rotor built in the roots blower and the amount of water injected into the casing containing the roots rotor according to the pressure of the collected exhaust steam, It is possible to introduce the vapor into the steam introduction path as an optimum pressure, saturated or close to the water content.

Schematic showing the pressureless exhaust steam refeeding type heating system of the present invention Roots blower structure diagram ((a) Front sectional view, (b) Side sectional view) Roots blower control unit enlarged view Graph showing steam flow rate in confirmation test Graph showing the temperature in the flow path of steam in the confirmation test

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  The pressureless exhaust steam re-feeding type heating system (1) of the present invention includes a steam introduction path (4) for introducing steam supplied from a boiler (2) into a heating chamber, and a non-pressure-contained object to be processed. A heating chamber (3) for heating with steam, and a steam recovery path (5) for recovering unpressured exhaust steam discharged from the heating chamber (3), and a roots blower (5) in the steam recovery path (5) 6), the recovered exhaust steam is pressurized and introduced into the steam introduction path (4), and the exhaust steam is resupplied to the heating chamber (3) (FIG. 1).

  Steam for heating an object to be processed such as food stored in the heating chamber (3) is supplied from the boiler (2) to the heating chamber (3) through the steam introduction path (4). Since the amount of steam supplied from the boiler (2) needs to be adjusted according to the type and amount of the object to be treated stored in the heating chamber (3), the pressure is placed in the middle of the steam introduction path (4). It is preferable to provide a regulating valve (7) and a pressure gauge (8) and a flow meter (9) for monitoring the pressure and flow rate of steam. In the preparatory stage before the heat treatment, it is necessary to replace the air in the heating chamber with steam. Therefore, it is preferable to increase the steam pressure, increase the supply amount, and shorten the preparation time.

  Steaming and sterilizing heat treatment of the workpiece carried into the heating chamber (3) is performed by injecting steam in the heating chamber (3), filling the heating chamber with normal pressure (no pressure) steam, and a temperature of about 100 ° C. To do.

  The steam in the heating chamber (3) is discharged to the outside of the heating chamber (3) along with the introduction of the steam from the steam introduction path (4). Conventionally, all the exhaust steam discharged from the heating chamber (3) has been released to the atmosphere through the vent (10). However, the non-pressure exhaust steam refeeding heating system (1) of the present invention is By recirculating and reusing steam, the surrounding environment is prevented from deteriorating due to conventional waste heat, and costs can be further reduced.

  The exhaust steam discharged from the heating chamber (3) is recovered via the steam recovery path (5). The recovered exhaust steam has a pressure lower than that before being introduced into the heating chamber (3). For this reason, in order to utilize the collect | recovered waste steam as a steam for heat-sterilizing again, it is necessary to raise a pressure.

  For this reason, a roots blower (6) is installed in the steam recovery path (5), and the recovered steam is pressurized and re-supplied to the steam introduction path (4). Since the roots blower can be operated at a relatively low rotation speed, the power cost can be kept low, and since the drive source is small, the size of the roots blower is relatively small, and the pressureless exhaust steam resupply heating system is large. Can be prevented.

  A pressure gauge (11a, 11b) and a pressure sensor (12) are installed in the steam recovery path (5), and the rotation of the roots blower (6) is adjusted according to the pressure of the recovered exhaust steam, and the steam introduction path ( It is preferable to re-supply exhaust steam having an appropriate pressure in 4).

  The roots blower (6) can deliver a certain amount of gas proportional to the rotational speed. Three-leaf root rotors (32, 32) mounted on two parallel axes, respectively, rotate in opposite directions while maintaining a slight gap in the oval casing (20) (working chamber). Thus, a certain amount of gas surrounded by the casing (20) and the roots rotor (32) can be sent from the suction side to the discharge side.

  In order to reuse the recovered exhaust steam as saturated steam, it is necessary to compress the water while replenishing it, thereby depriving it of superheat energy and preventing it from being superheated. For this reason, the roots blower (6) installed in the steam recovery path (5) is provided with a water inlet (21) and water is injected into the casing (20) containing the roots rotor (32) to prevent overheating steaming. However, the exhaust steam recovered can be reused as saturated steam (Fig. 2).

  Further, by injecting water into the casing (20), a water layer is formed on the inner surface of the casing (20) and the outer surface of the roots rotor (32), and the gap between the casing (20) and the roots rotor (32) is formed. Therefore, the airtightness of the space (27) is improved, and the operating efficiency (volumetric efficiency) of the Roots blower can be increased.

  The water injection port (21) is located above the casing (20) on the discharge port (25) side from the center of the roots rotor (32) so that the injected water reaches the entire inside of the casing (20) as the root rotor (32) rotates. It is preferable to provide in. As shown in FIG. 2, the roots blower (6) moves the suction port (19) by 120 ° from the center of each rotating shaft with respect to a virtual line a connecting the centers of the rotating shafts of each root rotor (32). The discharge port (25) is provided at an angular position b, and 120 in a direction opposite to the suction port (19) from the center of each rotation axis with respect to an imaginary line a connecting the centers of the rotation shafts of the roots rotors (32). Is provided at a position c at a volume movement angle of 0 °, and immediately after the suction of the steam, it is enclosed in two places on the suction port side and the discharge port side by the leaf pieces adjacent to each root rotor (32) and the inner wall surface of the casing (20). The water inlet (21) is provided in the peripheral wall portion at the position d which is provided so as to generate the space portion (27) and is returned by 80 ° from the position c to the suction port side. Note that a small gap of a certain size is provided between the inner wall surface of the casing (20) and the top of each leaf piece of the roots rotor (32).

  The bearing (30) and the timing gear (17) are lubricated with oil, but in order to prevent the steam and water from the casing from entering the lubricated part of the oil, the roots rotor (32) and the bearing (30) A structure in which a plurality of Teflon seals (26) are provided via a shaft sleeve (29) attached to the shaft (33), and an intermediate chamber (24) is provided between the Teflon seals (26). Is adopted.

  The root rotor (32) incorporated in the roots blower (6) is preferably made of austenitic spheroidal graphite cast iron. As a material of the roots rotor (32), stainless steel is generally adopted for the purpose of rust prevention. However, since stainless steel has a high coefficient of thermal expansion, the roots blower needs to be designed with a large clearance between the root rotors and between the root rotor and the casing inner surface. The roots blower of the present invention is made of austenitic spheroidal graphite cast iron to reduce the clearance between the root rotors and between the root rotors and the inner surface of the casing while preventing the occurrence of rust, and the operating efficiency (volumetric efficiency) of the roots blower. Is increasing. As the austenitic spheroidal graphite cast iron, for example, Nijirest D5 can be used.

  Since the amount of steam introduced into the heating chamber is adjusted according to the number of objects to be processed and the temperature to be processed, the amount of exhaust steam recovered from the heating chamber also changes according to these conditions. On the other hand, the recovered exhaust steam needs to be pressurized to a certain pressure so that it can be re-supplied to the heating chamber together with new steam supplied from the boiler. For this reason, a pressure sensor (12) is installed in the steam recovery path (5), and the rotational speed of the root rotor (32) built in the roots blower (6) is adjusted according to the pressure of the recovered steam to recover the recovered steam. The pressure is adjusted to increase to a certain level.

  As shown in FIG. 3, the signal from the pressure sensor (12) is processed and converted by the inverter (34) as a power signal of the electric motor (35) for driving the Roots blower. Thus, by controlling the rotation speed of the roots rotor in accordance with the pressure of the recovered steam, the recovered steam pressure can be increased to a constant pressure.

  In addition, by controlling the rotational speed of the roots rotor and the amount of water injected into the casing (20) according to the signal from the pressure sensor (12), the pressure of recovered steam and the amount of water are increased, and in a state close to the saturated steam pressure. It can be re-supplied to the steam introduction path (4).

  Furthermore, a separator (13) is installed in the steam recovery path (5) to remove the non-condensable air and the condensed water, thereby maintaining the steam in the steam recovery path close to the saturated vapor pressure. The condensed water is separated together with air as a drain, and the air is discharged to the outside through the automatic air vent valve (14).

  The confirmation test of the effect performed about the non-pressure exhaust-vapor resupply type heating system of this invention is described as an Example.

  When the amount of steam supplied from the boiler was changed over time, the amount of exhaust steam recovered from the heating chamber was measured, and the change in temperature at each part of the pressureless exhaust steam re-feeding heating system was measured. .

  FIG. 4 shows changes in the steam flow rate in the steam recovery path and the steam flow rate in the steam introduction path near the heating chamber. The flow rate of steam in the steam recovery path indicates the amount of recovered exhaust steam, and the flow rate of steam in the steam introduction path in the vicinity of the heating chamber indicates the steam supplied from the boiler and the exhaust steam re-supplied from the steam recovery path. It shows the quantity. In the confirmation test, the flow rate of steam is extremely changed. As shown in FIG. 4, when the amount of steam introduced into the heating chamber changes, the amount of recovered steam also changes, but it is introduced into the heating chamber. The amount of steam recovered with respect to the generated steam has changed at a rate of about 51 to 73%, and it has been confirmed that the pressureless exhaust steam resupply type heating system operates stably.

  FIG. 5 shows changes in the temperature in the steam introduction path near the boiler, the temperature in the steam recovery path, and the temperature in the heating chamber. In the confirmation test, although the flow rate of steam was extremely changed, as shown in FIG. 5, the temperature remained constant in each part, and the pressureless exhaust steam refeeding heating system was stably operated. I was able to confirm that.

DESCRIPTION OF SYMBOLS 1 Pressureless exhaust steam resupply type heating system 2 Boiler 3 Heating chamber 4 Steam introduction path 5 Steam recovery path 6 Roots blower 7 Pressure regulating valve 8 Pressure gauge 9 Flowmeter 10 Vent 11a Pressure gauge 11b Pressure gauge 12 Pressure sensor 13 Separator 14 Automatic air vent Valve 15 Check valve 16 Air vent 17 Timing gear 18 Gear cover 19 Suction port 20 Casing 21 Internal cooling port 22 Seal case 23 Oil sprinkling plate 24 Intermediate chamber 25 Discharge port 26 Teflon seal 27 Space 28 Housing 29 Shaft sleeve 30 Bearing 31 V pulley 32 Roots rotor 33 Shaft 34 Inverter 35 Electric motor

Claims (10)

A steam introduction path for introducing the steam supplied from the boiler into the heating chamber, a heating chamber for heating the contained object to be processed with non-pressure steam, and a non-pressure exhaust steam discharged from the heating chamber are collected. and a vapor recovery path for, Roots blower to the vapor recovery path, established the separator and automatic air vent valve, as well as the pressure of the recovered waste steam, to remove moisture condensed with non-condensable air other than steam A non-pressure exhaust steam re-feeding type heating system, wherein the exhaust steam is re-supplied to the heating chamber by being introduced into the steam introduction path.   2. The pressureless exhaust steam refeeding heating system according to claim 1, wherein water is injected into a casing having a root rotor of a roots blower, and the recovered exhaust steam is introduced into the steam introduction path as saturated steam.   The pressureless exhaust steam refeeding type heating system according to claim 1 or 2, wherein the roots rotor built in the roots blower is made of austenitic spheroidal graphite cast iron.   A pressure sensor is installed in the steam recovery path, the rotational speed of the roots rotor built in the roots blower is adjusted according to the pressure of the exhaust steam in the path, and the exhaust steam whose pressure is adjusted is introduced into the steam introduction path. The pressureless exhaust steam refeeding type heating system according to any one of claims 1 to 3.   A pressure sensor is installed in the steam recovery path, and the pressure and moisture volume are adjusted by adjusting the rotation speed of the roots rotor built into the roots blower and the amount of water injected into the casing containing the roots rotor according to the pressure of the exhaust steam in the path. The non-pressure exhaust steam refeeding type heating system according to any one of claims 1 to 4, wherein the exhaust steam is introduced into a steam introduction path. A steam introduction path for introducing the steam supplied from the boiler into the heating chamber, a heating chamber for heating the contained object to be processed with non-pressure steam, and a non-pressure exhaust steam discharged from the heating chamber are collected. and a vapor recovery path for, Roots blower to the vapor recovery path, established the separator and automatic air vent valve, as well as the pressure of the recovered waste steam, to remove moisture condensed with non-condensable air other than steam A non-pressure exhaust steam re-feed type heating method, wherein the exhaust steam is re-supplied to the heating chamber by being introduced into the steam introduction path. 7. The pressureless exhaust steam refeeding heating method according to claim 6 , wherein water is injected into a casing containing a root rotor of a roots blower, and the recovered exhaust steam is introduced into the steam introduction path as saturated steam. 8. The pressureless exhaust steam refeeding heating method according to claim 6 or 7, wherein the roots rotor incorporated in the roots blower is made of austenitic spheroidal graphite cast iron. A pressure sensor is installed in the steam recovery path, the rotational speed of the roots rotor built in the roots blower is adjusted according to the pressure of the exhaust steam in the path, and the exhaust steam whose pressure is adjusted is introduced into the steam introduction path. The pressureless exhaust steam refeeding heating method according to any one of claims 6 to 8 . A pressure sensor is installed in the steam recovery path, and the pressure and moisture volume are adjusted by adjusting the rotation speed of the roots rotor built into the roots blower and the amount of water injected into the casing containing the roots rotor according to the pressure of the exhaust steam in the path. No retraction steam re-fed heating method according to any one of claims 6 to 9 the waste steam and introducing the steam introduction routes.

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