JP2015117846A - Pipe dryer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe dryer capable of drying a pipe efficiently in a short time with a simple structure.SOLUTION: A pipe dryer includes: a thermal insulation plate 2 installed on an upper surface of a floor; a cover sheet 5 covering tubes held above the thermal insulation plate 2, the cover sheet 5 as well as the thermal insulation plate 2 forming a heating space 4 around the pipes 1; a fan duct 6 having one end inserted into the heating space 4; and a hot-blast feeder 7 connected to the other end of the fan duct 6, and feeding hot blast into the heating space 4 via the fan duct 6, the pipes 1 being forcedly dried by the hot blast in the heating space 4. With this configuration, it is possible to ensure shorter time for drying the pipes 1 than that required with a method based on a combination of preheating and natural drying of pipes. An overall structure is quite simple as compared with a drying system such as a gas furnace, and it is possible to efficiently dry the pipes 1 depending on the number of pipes 1 to be dried.

Description

  The present invention relates to a drying device for drying painted tubes.

  Metal pipes such as cast iron pipes used for water pipes and gas pipes buried in the ground are usually subjected to anticorrosion coating to prevent corrosion in the ground before factory shipment. However, if the metal tube after anticorrosion coating is used in a state where the solvent such as xylene contained in the coating does not sufficiently evaporate, solvent odor may be a problem.

  In particular, cast iron pipes are often provided with both ends of a straight portion having a constant inner and outer diameter, and a receiving opening having a larger inner and outer diameter than the straight portion and an insertion port to be inserted into a receiving port of another cast iron pipe ( Hereinafter, the receiving port and the insertion port are collectively referred to as a “joint portion”.) When the insertion port is inserted into the receiving port of another cast iron pipe and used as a water pipe, it receives water flowing inside the pipe. There is a possibility that the solvent contained in the coating film on the inner surface of the mouth and the outer surface of the insertion port may be leached and affect the water quality.

  On the other hand, the Japan Water Works Association Standard JWWA K 139 states that “the coating film must be sufficiently dried by factory shipment in consideration of the coating film performance and the water quality after passing water, especially odor”. Has been. However, if the coating film on the tube is sufficiently dried by natural drying, the drying period after painting becomes longer, so it takes longer time from manufacture to shipment in the factory that manufactures the tube, The problem is that a large space is taken to hold the tube to be used.

  On the other hand, it is generally known that the cast iron pipe is preheated before painting in order to perform the coating at an appropriate temperature according to the paint. It is said that the cast iron pipe coating can be dried in a short time (for example, see Patent Document 1).

JP 2012-223695 A

  However, in the method of preheating the pipe before painting as described above, the pipe temperature is rapidly lowered by the outside air temperature at the initial stage of natural drying after painting, so the drying period cannot often be shortened effectively. Especially in winter, the drying period becomes longer.

  On the other hand, if the tubes are forced to dry using a drying facility such as a gas furnace, the drying period can be shortened reliably, but a large facility is required and the number of tubes to be dried Even when there is a small amount, the entire large heating space must be heated, resulting in an increase in manufacturing cost and running cost.

  Accordingly, an object of the present invention is to provide a tube drying apparatus capable of drying a tube efficiently and in a short time with a simple structure.

  In order to solve the above problems, the tube drying apparatus of the present invention covers a tube held above a floor and forms a heating space around the tube, and one end is inserted into the heating space. And a hot air supply device that is connected to the other end of the air duct and sends hot air to the heating space via the air duct. In this configuration, the drying period of the tube can be reliably shortened by forced drying with hot air, and the heating space around the tube is formed only by the cover sheet and the upper surface of the floor, so the entire structure compared to a gas furnace etc. Is extremely simple, and by changing the size of the cover sheet in accordance with the number of tubes to be dried, the size of the heating space can be adjusted to efficiently dry the tubes.

  In the above configuration, a heat insulating plate that is formed of a heat insulating material and forms the heating space together with the cover sheet is installed on the upper surface of the floor, or one end portion is inserted into the heating space, and the other end portion is connected to the hot air. By providing an intake duct connected to the intake part of the supply machine and circulating hot air between the heating space and the hot air supply machine, the temperature of the heating space can be increased in a shorter time, and the drying period Can be further shortened.

  Further, if one end portion of the air duct is disposed below a predetermined portion of the pipe, and an air outlet that blows hot air toward the periphery of the predetermined portion of the pipe is provided at one end portion of the air duct, drying is performed. By setting the part having the highest demand for the predetermined part as the predetermined part and promoting the drying of the predetermined part, the drying period can be further shortened.

  Here, a plurality of the pipes are held in parallel in the horizontal direction, and a plurality of outlets of the air duct are provided in the direction in which the pipes are arranged, and the plurality of outlets have an opening area on the side close to the hot air supply machine. By adopting a configuration in which the opening area of the far side is formed larger than that, it is possible to suppress variation in the drying speed of a predetermined portion of each tube, and as a result, it is possible to efficiently dry a plurality of tubes in a short time.

  And when the said pipe | tube has a joint part in both ends, this invention can be applied effectively by making the said joint part into the said predetermined part.

  As described above, the tube drying apparatus of the present invention forcibly dries the tube with hot air in the heating space formed by the cover sheet and the upper surface of the floor. Compared with the shortening method, the drying period of the tube can be shortened reliably. Compared with drying equipment such as a gas furnace, the overall structure is extremely simple, and the tube can be efficiently used according to the number of tubes to be dried. Can be dried, so that the manufacturing cost and running cost can be greatly reduced.

The top view except the cover sheet of the drying apparatus of the pipe of a 1st embodiment. a is a plan view of the tube drying apparatus according to the second embodiment except for a cover sheet and a heat insulating cover, and b is a cross-sectional view taken along line II-II of a. a is a plan view of the drying apparatus in FIG. 2 in a state where the heat insulating lid is used, b is a front view of a, and c is a cross-sectional view taken along line III-III of b.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment. This tube drying device is for drying a plurality of coated tubes 1 and is placed on the heat insulating plate 2 having a substantially rectangular flat plate shape installed on the upper surface of the floor, and on the upper surface of the heat insulating plate 2. Two holding members 3 that hold the tube 1 above, a cover sheet 5 that covers the tube 1 and the holding member 3, and forms a heating space 4 around the tube 1 together with the heat insulating plate 2, and one end portion of the heating space 4 A blower duct 6 that is inserted and opened at the tip thereof and a hot air supply device 7 that is connected to the other end of the blower duct 6 and sends hot air to the heating space 4 through the blower duct 6 are provided. Although not shown, a sheet support member that supports the cover sheet 5 so as not to directly touch the tube 1 is arranged in the heating space 4 so that hot air flows smoothly through the heating space 4. .

  The pipe 1 to be dried by this drying apparatus is a cast iron pipe used as a water pipe, and at both ends of a straight portion 1a having a constant inner and outer diameter, a receiving port 1b having a larger inner and outer diameter than the straight portion, and other cast iron An insertion port 1c to be inserted into the receiving port of the tube, arranged in parallel in the horizontal direction and alternately in the longitudinal direction, and supported at two locations in the longitudinal direction by the holding member 3 ing.

  The heat insulating plate 2 is for blocking heat dissipation from the heating space 4 to the floor, and is formed of a heat insulating material such as expanded polystyrene. Moreover, in order to suppress the heat dissipation from the heating space 4 to the atmosphere, it is desirable to use a cover sheet 5 having a heat insulating property.

  Moreover, although description is abbreviate | omitted in FIG. 1, the upper surface of the peripheral part of the heat insulating board 2 prevents the cover sheet 5 from being turned up by sandwiching the cover sheet 5 together with the heat insulating board 2 as in the second embodiment described later. A weight of wood or the like (see FIG. 2B (reference numeral 8)) is placed. As a result, the heating space 4 is almost closed. However, when hot air is fed into the heating space 4 from the hot air supply device 7, the air in the vicinity of the peripheral edge of the heat insulating plate 2 flows from the gap between the heat insulating plate 2 and the cover sheet 5. Released into the atmosphere.

  This drying apparatus is configured as described above, and the tube 1 is forcibly dried by hot air in the heating space 4 formed by the heat insulating plate 2 and the cover sheet 5 installed on the upper surface of the floor. The drying period can be reliably shortened as compared with the conventional method of preheating a tube. Moreover, the overall structure is extremely simple compared to a drying facility such as a gas furnace, and the size of the heating space 4 can be reduced by changing the size of the cover sheet 5 according to the number of tubes 1 to be dried. The tube 1 can be efficiently dried by adjusting.

  In addition, when the heat insulating property of the floor is high, the heat insulating plate 2 may be omitted. In that case, the heating space 4 is formed by the cover sheet 5 and the upper surface of the floor.

  2 and 3 show a second embodiment. Since this embodiment is based on the first embodiment, members having the same functions as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. Hereinafter, differences from the first embodiment will be mainly described. To do.

  First, as shown to Fig.2 (a), (b), in this 2nd Embodiment, the some pipe | tube 1 is hold | maintained on the heat insulation board 2 in the stacked state. That is, the first-stage tube 1 is held by the holding member 3 placed on the upper surface of the heat insulating plate 2, and another prismatic holding member 9 is placed on the first-stage tube 1. The second stage tube 1 is held.

  And it replaces with the air duct 6 of 1st Embodiment, and the air duct 10 divided into the forked part in the vicinity of the connection end with the blowing part 7a of the hot air supply machine 7 is used. The air duct 10 has two end portions (one end portion) 11 divided into one end side and the other end side of each tube 1 and inserted into the heating space 4, respectively, between the heat insulating plate 2 and the first-stage tube 1. It arrange | positions so that it may extend along the lower side of the joint part (receiving port 1b and insertion port 1c) of each pipe | tube 1. As shown in FIG.

  The front end portion 11 of the air duct 10 is closed at the front end opening, and a plurality of upward air outlets 11a are provided at predetermined intervals along the longitudinal direction (the direction in which the tubes 1 are arranged). Hot air is blown out from the outlets 11a toward the periphery of the joints 1b and 1c of the pipes 1. Further, the air outlet 11a is formed so that the opening area on the side closer to the hot air supply machine 7 is larger than the opening area on the far side, so that variations in the amount of hot air blown out can be suppressed. For this reason, compared with 1st Embodiment using the ventilation duct 6 which blows off hot air from front-end | tip opening, the variation in the air temperature in the heating space 4 can be made small.

  Here, it is desirable that the total opening area of the air outlet 11 a of the air duct leading end 11 is 90% or more of the opening area of the air outlet 7 a of the hot air supply machine 7. In this way, it is possible to sufficiently secure the total amount of hot air sent into the heating space 4, so that the air flow in the heating space 4 is improved, the moving speed of the air contacting the tube 1 is increased, and the coating of the tube 1 is increased. Volatilization of the solvent contained in the film can be promoted.

  Moreover, the intermediate part 13 between the front-end | tip part 11 of the ventilation duct 10 and the connection part (other end part) 12 to the hot air supply machine 7 is formed with the hose which can be expanded-contracted. Thereby, even if the length of the pipe 1 to be dried is changed and the positions of the joint portions 1b and 1c of the pipe 1 in the heating space 4 are changed, the air duct leading end portion 11 can be easily arranged at the corresponding position. It is like that.

  Furthermore, in this embodiment, an air intake duct 14 is provided in which one end portion is inserted into the heating space 4 and the other end portion is connected to the air intake portion 7 b of the hot air supply machine 7. The intake duct 14 has an end at one end that opens to the lowermost center of the heating space 4 where the temperature is the lowest, and intake is performed from the end opening. Thereby, a hot air can be circulated between the heating space 4 and the hot air supply machine 7, and the temperature of the air of the heating space 4 can be raised in a shorter time than 1st Embodiment.

  Further, on the joint portions 1b and 1c at both ends in the longitudinal direction of each pipe 1 in the second stage, a heat insulating lid 15 extending in the direction in which the tubes 1 are arranged is placed, and above the joint portions 1b and 1c of each pipe 1, A space in which high-temperature air blown out from the air outlet 11a of the air duct 10 stays is formed. As shown in FIGS. 3A to 3C, the heat insulating lid 15 is formed along a rectangular lid plate 15a covering the joints 1b and 1c of the tube 1 and both side edges of the lower surface of the lid plate 15a. The mounting portions 15b and 15c each have a rectangular column shape, and end plates 15d (shown only on one end side) provided at both ends in the longitudinal direction of the lower surface of the cover plate 15a. The whole is formed of a heat insulating material such as expanded polystyrene. Yes. One of the mounting portions 15b and 15c is mounted on the receiving port 1b of the tube 1 and the other is mounted on the straight portion 1a and the insertion port 1c. Therefore, the outer diameter difference between the receiving port 1b and the straight portion 1a and the insertion port 1c A step corresponding to (the straight portion 1a and the insertion opening 1c has the same outer diameter) is formed between the lower surface positions of both the placement portions 15b and 15c, and can be stably placed on the plurality of tubes 1. . One end plate 15d is rotatably attached to the lid plate 15a so that the heat retaining lid 15 can be easily placed on the tube 1.

  In the second embodiment, when the pipe 1 is used as a water pipe, the dryness of the joint portions 1b and 1c may affect the water quality. Therefore, as described above, the joint portion 1b of the pipe 1 The hot air is intensively blown to 1c to forcibly accelerate the drying of the joint portions 1b and 1c, and the hot air is circulated between the heating space 4 and the hot air supply device 7 so that the air in the heating space 4 is shortened in a short time. The temperature of the joint 1b and 1c of the pipe 1 is put on the heat insulating lid 15 so that the temperature rise of the joints 1b and 1c is accelerated. It can be further shortened than the form.

  In addition, although FIG. 2 shows an example of stacking in two stages, if there are many cast iron pipes to be dried, the number of stages can be increased and the drying operation can be performed more efficiently.

  Moreover, about the opening area of the blower outlet 11a of the ventilation duct front-end | tip part 11, as a result of performing various experiments, for example, when there are 13 blower outlets 11a, when all the hole diameters are 20 mm (Experimental example 1), hot air The wind speed on the side farther from the side closer to the feeder 7 becomes faster and the air volume per unit time increases, whereas the diameter of the four holes nearer to the hot air feeder 7 is set to 30 mm, and the other nine When the hole diameter was 20 mm (Experimental Example 2), it was confirmed that the air speed (air volume) of each outlet 11a became substantially constant, and variation in the air temperature in the heating space 4 could be suppressed.

  And when performing drying operation using the drying apparatus of each embodiment mentioned above, it is desirable to adjust the temperature of hot air, and the total air volume so that the temperature of the pipe | tube 1 may be 40-60 degreeC. The higher the temperature of the tube 1, the shorter the time required for drying, but if the temperature is too high, the coating film softens and adheres to the holding member 3 or the like, or adheres to the coating film of the adjacent tube 1, This is because when the dried tube 1 is taken out from the drying apparatus, the coating film may be peeled off.

  For example, in the drying apparatus according to the second embodiment, the cast iron pipes 1 having a nominal diameter of 75 mm are stacked in 19 × 8 stages, and the air duct 11 has a hole diameter of the outlet 11a of the above-described experimental example 2. As a result of the experiment, assuming that the hot air temperature at the outlet 11a of the air duct 10 is 100 to 120 ° C., the temperature of the joint portions 1b and 1c of all the tubes 1 is 40 to 50 ° C. after about 5 hours from the start of the hot air supply. We were able to. When the hot air temperature exceeds 120 ° C, the case where the temperature of the joint portions 1b and 1c of some pipes 1 exceeds 60 ° C occurs. When the hot air temperature is less than 100 ° C, the temperature of the joint portions 1b and 1c is less than 40 ° C. The drying time becomes longer.

  Next, an experiment confirming the drying period shortening effect of the present invention will be described. In the experiment, a cast iron pipe having a nominal diameter of 75 mm painted with a paint containing xylene was used to forcibly dry it with the drying apparatus of the second embodiment after painting (Example), and after preheating and painting, The dried samples (comparative examples) were subjected to leaching tests to compare the amount of xylene leached. In the leaching test, each cast iron pipe to be tested was cut at the center in the longitudinal direction, washed with running water (5 to 6 liters / minute) for 1 hour with the insertion hole inserted into the receiving port, and then the inside of the pipe with tap water. It was filled and held, and after 16 hours, tap water in the pipe was collected and the xylene concentration was measured. In the examples, forced drying was performed for 8 hours on the next day of coating, and a leaching test was performed on the next day. The comparative example was subjected to a leaching test after 2 days and 6 days after coating. The results are shown in Table 1.

  As is apparent from Table 1, in the examples, the xylene concentration was considerably lowered after 2 days of coating and the odor of xylene was almost eliminated, whereas in the comparative example, the xylene concentration was high after 2 days and the odor of xylene was lost. Quite a bit remains, and after 6 days the xylene concentration has finally dropped to a level close to that of the example. Thereby, according to this invention, it was confirmed that a drying period can be shortened significantly compared with the method which combined the conventional preheating and natural drying.

  The drying device of the present invention is particularly effective when drying a cast iron pipe having a receiving port and an insertion port as described above. However, the present invention is not limited to this, and it is useful for drying various coated tubes. Can be widely used.

1 pipe (cast iron pipe)
1b Receiving port (joint part)
1c Insertion (joint part)
2 Insulating plate 4 Heating space 5 Cover sheet 6 Blowing duct 7 Hot air supply machine 7a Blowing part 7b Intake part 10 Blowing duct 11 Tip part (one end part)
11a Air outlet 12 Connection part (other end part)
13 Intermediate part 14 Intake duct 15 Thermal insulation lid

Claims (6)

  A cover sheet that covers a pipe held above the floor and forms a heating space around the pipe, a blower duct that has one end inserted into the heating space, and a blower duct that is connected to the other end of the blower duct. A tube drying apparatus comprising: a hot air supply device for sending hot air to the heating space via the air.   The apparatus for drying a tube according to claim 1, wherein a heat insulating plate made of a heat insulating material and forming the heating space together with the cover sheet is installed on the upper surface of the floor.   One end is inserted into the heating space, and the other end is provided with an intake duct connected to the intake portion of the hot air supply machine, and hot air is circulated between the heating space and the hot air supply machine. The tube drying apparatus according to claim 1 or 2.   The one end portion of the air duct is disposed below a predetermined portion of the pipe, and an air outlet that blows hot air toward the periphery of the predetermined portion of the pipe is provided at one end portion of the air duct. The tube drying apparatus according to any one of 1 to 3.   A plurality of the pipes are held in parallel in the horizontal direction, and a plurality of outlets of the air duct are provided in the direction in which the pipes are arranged, and the plurality of outlets are located on the far side of the opening area of the one close to the hot air supply machine. 5. The tube drying apparatus according to claim 4, wherein the tube drying device is larger than an opening area of the object.   The said pipe | tube has a joint part in both ends, The joint part is the said predetermined part, The drying apparatus of the pipe | tube of Claim 4 or 5 characterized by the above-mentioned.

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