JP2009280233A - Shrink packaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To save power consumption of a shrink packaging apparatus by changing the capacities of a required number of heat sources through switching their respective circuits, thereby keeping the inside of the furnace at temperature suitable for shrinking operation. <P>SOLUTION: The shrink packaging apparatus comprises: a box-shaped furnace casing whose both ends are open and which is formed from porous walls; an air heating chamber formed between the periphery of the furnace casing and an external body; a fan disposed in the heating chamber for circulating hot air, and the required number of the heat sources including electric heaters; and a conveyor disposed at the bottom in the furnace casing. In the shrink packaging device, the heat sources are connected by three connections, i.e., a Y connection, a &Delta; connection, and a V connection, to be associated with one another. The capacities of the heat sources are controlled by switching the circuits formed by the three connections. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an apparatus for shrinking and packaging a heat-shrinkable packaging film placed on an article to be packaged with hot air.

An ordinary shrink wrapping device has an air heating chamber formed between a box-shaped perforated wall furnace body open at both ends and an exterior body surrounding the furnace body, and is provided on both upper sides of the heating chamber. The air is heated by the required number of electric heaters, and hot air is circulated through the perforated wall between the furnace and the heating chamber by a fan provided in the upper part of the heating chamber, and then transferred to a conveyor disposed at the bottom of the furnace The product packaging film is shrunk with hot air, and the packaged product is tightly packed.
JP 2003-292030 A

  In the above shrink device, the heating time is shortened by increasing the heat source capacity at the start-up, and even after the furnace temperature reaches the set temperature, the electric heater is turned on / off without changing the heat source capacity. . For this reason, since the heat source capacity remains the same, power consumption tends to increase. In addition, an expensive step-down device such as a transformer is attached to the primary side of the heat source device to save power.

  The present invention has been conceived in order to solve the above-described conventional problems, and its purpose is to change the heat source capacity by switching the circuit of the required number of heat sources and to make the furnace temperature suitable for shrink work. An object of the present invention is to provide a new shrink wrapping apparatus which maintains the temperature and thereby saves power consumption.

  According to the above-mentioned object, the present invention provides a heating chamber for air formed between a box-shaped porous wall furnace open at both ends and an outer casing around the furnace body, and a hot air circulation fan provided in the heating chamber. And a required number of heat sources by an electric heater, and a conveyor disposed at the bottom of the furnace, and the heat sources are connected to each other by three connections of Y connection, Δ connection, and V connection, and a circuit of the three connections The heat source capacity is controlled by switching between the two.

  In addition, the heat source is an even number consisting of at least six, the same number is arranged on both sides of the upper part of the heating chamber, the heat sources on both sides are connected by the three connections, and the fans are related to each other. It is controlled by the temperature inside the furnace, and is configured to be controlled at low speed or stopped until the heat source reaches a set temperature at startup.

  In the above configuration, the heat source capacity is different for Y connection, Δ connection, and V connection. When the heat source capacity of Y connection is 100%, it becomes 75% for Δ connection and 50% for Y connection, which is a comparison with heat source capacity 100%. In this case, the heat source capacity is 5 to 10% when the heat source capacity is 75% and 12 to 20% when the heat source capacity is 50%. Therefore, the circuit of the heat source is switched to Δ connection or V connection depending on the temperature in the furnace, and the heat source capacity is 100%. Since the shrink wrapping can be performed by suppressing to 75% or 50%, the power consumption is reduced, and the shrink wrap having a good finished state can be efficiently performed with power saving.

  Also, the operation of the fan at start-up is stopped or controlled at a low speed until the heat source reaches the set temperature, and the rise of the heat source is shortened by eliminating the influence of the cool air by the fan, so the furnace temperature rise time is shortened In addition, since it is not necessary to increase the heat source capacity and increase the heating time as in the conventional case, power consumption during startup can be saved, and an expensive step-down device such as a transformer needs to be installed to save power. Since it disappears, it also reduces cost.

  In the figure, 1 is a box-shaped furnace body that is open at both ends, and a large number of flow holes 12a, 13a are formed at equal intervals throughout the wall plate of the side wall 12 and the bottom wall 13 excluding the upper wall 11. An outflow hole 11 a is formed in the central portion of the upper wall 11.

  Reference numeral 2 denotes an exterior body of the furnace body 1, which has a box shape that surrounds the periphery of the furnace body 1 except for the opening end and seals the periphery of the opening end, and forms an air heating chamber 3 between the periphery of the furnace body 1. The required width is provided at an interval.

  In the upper center of the heating chamber 4, a hot air circulation fan 4 is provided facing downward and facing the outflow hole 11 a of the upper wall 11. In addition, three electric heaters are arranged along the longitudinal direction as heat sources 5 and 5 for hot air at both upper corners of the heating chamber 4. The air heated by the heat sources 5 and 5 becomes hot air by the fan 4 and flows into the furnace 6 through the through holes 12a and 13a, and then returns to the upper portion of the heating chamber 3 through the outflow hole 11a of the upper wall 11. Then, it is again heated by the heat sources 5 and 5 and flows into the furnace 6. The temperature in the furnace is kept at the set temperature by such circulation of hot air.

  7 is a conveyor disposed horizontally on the bottom of the furnace, and is movably provided from one opening end of the furnace body 1 to the other opening end. The conveyor 7 is covered with a heat-shrinkable packaging film. The packaged article 8 is transferred into the furnace 6 and shrink wrapping of the packaging film with hot air is performed while passing through the furnace 6. Reference numeral 9 denotes a warming shield for insulating the furnace body opening.

  The heat sources 5 and 5 include six electric heaters 5a, 5b, and 5c disposed in any one of the upper corners of the heating chamber 4, and electric heaters 5a ', 5b', and 5c 'disposed in the other. These electric heaters are related to each other by a three-connection circuit shown in each diagram of FIG. 3, and the heat source capacity can be controlled by switching the circuits.

  In FIG. 3A, the connection of six electric heaters is a two-circuit Y connection, which can be used as a heat source capacity of 100%. FIG. 3 (B) shows the connection of 6 electric heaters as a series Δ connection, which can be used as a heat source capacity of 75%. FIG. 3 (C) shows the case where four electric heaters are used and two electric heaters are connected in series with a V connection, and the heat source capacity is 50%. In addition, although there is a certain difference in power consumption depending on the set temperature, the energy saving is 5 to 10% when the heat source capacity is 75% and 12 to 20% when the heat source capacity is 50% compared to the heat source capacity of 100%.

  Next, an example of the work process will be described. First, the start switch is turned on. As a result, the motors of the fan 4 and the conveyor 7 (not shown) are turned on, the fan 4 rotates at a low speed, and the conveyor 7 circulates. At the same time, the Y connection (A) circuit of the heat sources 5 and 5 is turned ON, and the six electric heaters generate heat when energized to heat the air in the heating chamber 3. The air is heated by the fan 4 while circulating through the heating chamber 3 and the furnace 6. When the fan 4 is blown at a low speed, the air in the heating chamber is moved at a slow speed, so that the cooling of the heat sources 5 and 5 due to the blow in the temperature rising process is suppressed, and thus the heat sources 5 and 5 are suppressed. Reaches the set temperature early and the rise time is shortened.

  The temperature in the furnace 6 is constantly detected by a temperature detector (not shown), and when the furnace temperature reaches the set temperature with a heat generation capacity of 100% by the circuit of the Y connection (A), the fan is detected by detecting the temperature. The motor output No. 4 is switched from a low speed rotation to a normal rotation speed higher than that. After this switching, the article to be packaged 8 covered with the packaging film is transferred to the furnace 6 by the conveyor 7, and shrink wrapping with hot air is performed while passing through the furnace 6.

  When the furnace temperature is stabilized, the heat sources 5 and 5 are switched from the Y-connection (A) circuit to the V-connection (C) circuit with a heat source capacity of 50%, and the heat source capacity is secondarily controlled. Hold and shrink-wrap. Depending on the heat shrinkability of the shrink film, the shrink working temperature in the furnace is set to T ° C or higher in advance, and the detected temperature T ° C-2 ° C of the furnace temperature is set as the lower limit value. Is switched from a circuit of V connection (C) to a circuit of Δ connection (B) having a heat source capacity of 75%, and the furnace temperature is raised to a set temperature of T ° C. or higher. When it is detected that the set temperature has been reached, the circuits of the heat sources 5 and 5 are switched again to the circuit of the V connection (C) to maintain the shrink working temperature.

  Therefore, the heating with the heat source capacity of 100% is performed only at the time of start-up, and the shrink work is efficiently performed while maintaining the set temperature in the range of the heat source capacity of 75% to 50%, thereby reducing power consumption.

In the above-described work process, the rotation of the fan 4 at the time of start-up is set to a low-speed rotation until reaching the set temperature. However, in some cases, the fan 4 is stopped until the temperature in the furnace 6 reaches the set temperature. It may start after reaching the normal rotation.
When the room temperature is low or the packaged article 8 is a low-temperature product, the setting is switched from the Y connection (A) circuit with a heat source capacity of 100% or the Δ connection (B) circuit with a heat source capacity of 75%. It is preferable to maintain the temperature.

It is a vertical front view of the shrink wrapping apparatus concerning this invention. It is a vertical side view same as the above. It is a circuit diagram by 3 connection of the heat source by six electric heaters.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Furnace body 2 Exterior body 3 Air heating chamber 4 Fan for hot air circulation 5 Heat source of hot air 6 Furnace 7 Conveyor 8 Packaged article 11a Outflow hole 12a, 13a Inflow hole

Claims (3)

The air heating chamber formed between the box-shaped perforated wall furnace body open at both ends and the exterior body surrounding the furnace body, and the required number of hot air circulation fans and electric heaters provided in the heating chamber It consists of a heat source and a conveyor arranged at the bottom of the furnace,
A shrink wrapping apparatus comprising: a configuration in which the heat sources are connected by a Y-connection, a V-connection, and a Δ-connection, and the heat source capacity is controlled by switching a circuit of the three connections.   2. The heat source comprises an even number of at least six, and the same number is disposed on both sides of the upper portion of the heating chamber, and the heat sources on both sides are connected by the three connections and are related to each other. Shrink wrapping equipment.   2. The shrink wrapping apparatus according to claim 1, wherein the fan is controlled by a furnace temperature, and is configured to be controlled at a low speed or stopped until the heat source reaches a set temperature at startup.

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