JP4166713B2 - Piping with heater and its connection method - Google Patents

Description

  The present invention relates to a technique for improving heat insulation and thawing performance at a pipe end, particularly in a pipe with a heater for transferring various fluids.

In water supply facilities and gas analyzers in cold regions, problems occur when the inside of the pipe is condensed or frozen, and therefore, Japanese Patent Application Laid-Open No. 2003-27535 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2002-246157 (Patent Document 2). A pipe with a heater as described in 1 is used. As shown in FIG. 5, the heater-equipped piping has a cord-shaped heater 2 and a lead wire 3 along a tube 1, and a soaking layer 4, a heat insulating layer 5, a binding layer 6 and a protective cover 7 are sequentially disposed around the heater. Make the structure.
Japanese Patent Laid-Open No. 2003-27535 JP 2002-246157 A

  By the way, when connecting the pipe to various devices, at least the heat insulating layer 5, the binding layer 6 and the protective cover 7 disposed at the end thereof must be peeled off to expose the tube 1. For this reason, the amount of heat generated in the cord-like heater 2 is dissipated to the periphery at the pipe end, and the heat retention and thawing performance of the end must be inferior to the center. In order to compensate for the amount of heat radiated from the end of the pipe, it is conceivable to increase the heater capacity over the entire length of the pipe, but the capacity of the generator (generator) and battery is particularly limited for pipes mounted on vehicles. It was not realistic to take such measures.

  Therefore, in view of the conventional problems as described above, the present invention doubles the amount of heat generated by multiplexing the heaters located at the end of the pipe, and suppresses the power consumption of the heater as much as possible while reducing the total length of the pipe. It is an object of the present invention to provide a pipe with a heater capable of exhibiting a substantially uniform heat retention and thawing performance over a long period of time and a connection method thereof.

For this reason, in the first aspect of the present invention, a pipe for transferring a fluid, a cord-like heater provided along the substantially entire length of the pipe, and a heat insulating layer provided around the pipe and the heater, , The heater located at the end of the pipe has a predetermined length multiplexed by connecting a cord-like heater to the end. And
The invention according to claim 2 is characterized in that a soaking layer is provided between the pipe and the heater and the heat insulating layer to transmit the amount of heat generated by the heater to the outer periphery of the pipe substantially uniformly.
In the invention according to claim 3, a cord-shaped heater is disposed along substantially the entire length of the pipe for transferring the fluid, and the pipe with the heater having at least a heat insulating layer disposed around the pipe and the heater is opposed. When connecting to the equipment, peel off the heat insulation layer from the end to expose a part of the pipe and heater, and after connecting the pipe end to the counterpart equipment, the exposed heater is multiplexed, A heat insulating layer is disposed around the exposed piping and heater.

In the invention according to claim 4, a cord-like heater is disposed along substantially the entire length of the pipe for transferring the fluid, and the pipe with the heater having at least a heat insulating layer disposed around the pipe and the heater. When connecting to the equipment, peel off the heat insulation layer from the end to expose a part of the pipe and heater, and after connecting the pipe end to the counterpart equipment, the exposed heater is multiplexed, A soaking layer and a heat insulating layer are disposed around the exposed pipe and heater.
The invention according to claim 5 is characterized in that the heat insulating layer is further covered with a heat shrinkable tube.
The invention according to claim 6 is characterized in that the heaters are multiplexed by folding back end portions thereof.
The invention according to claim 7 is characterized in that the heaters are multiplexed by connecting a cord-like heater at the end thereof.

According to the first aspect of the present invention, at the end of the pipe with heater, a portion of a predetermined length of the heater disposed along substantially the entire length of the pipe for transferring the fluid is multiplexed. When applied, the amount of heat generated at the site doubles, and the heat retention and thawing performance of the end can be improved while suppressing the power consumption of the heater as much as possible. At this time, if the predetermined length to be multiplexed is appropriately set according to the capacity of the heater, the applied current, etc., substantially uniform heat retention and thawing performance is exhibited over the entire length of the pipe with heater, and the fluid to be transferred is Insulate and thaw effectively. In addition, since the heater located at the end of the pipe is multiplexed by connecting a cord-like heater to the end, even if the heater is not flexible enough to be folded back, Can be easily multiplexed .

According to the second aspect of the present invention, the amount of heat generated by the heater is transmitted substantially uniformly to the outer periphery of the pipe by the soaking layer. The temperature distribution of the dripping fluid becomes substantially uniform, and the frozen fluid can be thawed in a short time.
According to the third aspect of the present invention, the heater-equipped pipe is exposed after peeling off the heat insulating layer located at the end thereof to expose a part of the pipe and the heater and connecting the counterpart device to the pipe end. Multiple heaters are multiplexed, and a series of procedures of arranging a heat insulating layer around the exposed pipe and the heater are sequentially performed to connect to the counterpart device. For this reason, it becomes easy to implement | achieve the piping with a heater which concerns on this invention using the piping with a heater of a general-purpose product, and reduction of a manufacturing cost etc. can be aimed at effectively.

According to the invention described in claim 4 , in addition to the operation and effect of the invention described in claim 3, since the soaking layer and the heat insulating layer are disposed around the pipe and the heater, the amount of heat generated by the heater is equalized. Since the heat is transmitted almost uniformly to the outer periphery of the pipe by the heat layer, the inside of the pipe is heated substantially uniformly from the outer periphery, the temperature distribution of the fluid to be transferred becomes substantially uniform, and the frozen fluid is kept in a short time. Can be thawed.
According to invention of Claim 5, the circumference | surroundings of a heat retention layer can be coat | covered with a heat contraction tube.

According to the invention described in claim 6 or claim 7, the predetermined length of the heater positioned at the end of the pipe is obtained by folding back the heater end or connecting a cord-like heater to the end of the heater. These sites can be multiplexed. In particular, according to the seventh aspect of the present invention, even if the heater has low flexibility and cannot be folded back, the end portions can be easily multiplexed.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an implementation in which a pipe with a heater according to the present invention is applied to an exhaust gas purification device that uses an aqueous urea solution as a reducing agent and purifies nitrogen oxides (NOx) contained in engine exhaust by a catalytic reduction reaction. The form is shown.
An exhaust pipe 14 connected to the exhaust manifold 12 of the engine 10 includes an oxidation catalyst 16 that oxidizes nitrogen monoxide (NO) to nitrogen dioxide (NO ₂ ) along the exhaust flow direction, and according to engine operating conditions. Injection nozzle 18 for supplying and supplying the required amount of urea aqueous solution, NOx reduction catalyst 20 for reducing and purifying NOx with ammonia obtained by hydrolyzing the urea aqueous solution, and ammonia oxidation for oxidizing the ammonia that has passed through the NOx reduction catalyst 20 A catalyst 22 is provided. In addition, the urea aqueous solution stored in the storage tank 24 is supplied to the injection nozzle 18 in a sprayed state mixed with air via the heater-equipped pipe 26 and the reducing agent supply device 28. On the other hand, surplus urea aqueous solution supplied to the reducing agent supply device 28 is returned to the storage tank 24 through the pipe 30 with heater. Here, the reason why the storage tank 24 and the reducing agent supply device 28 are connected by the heater-equipped pipes 26 and 30 is that the freezing point (freezing point) of the urea aqueous solution is about 11 ° C. below freezing point. This is because when the vehicle travels, the urea aqueous solution supplied from the storage tank 24 to the reducing agent supply device 28 is frozen, and the NOx purification performance may not be obtained or deteriorated due to the shortage of the reducing agent. In addition, it is desirable to control the heater-equipped pipes 26 and 30 so that the heaters are appropriately operated according to, for example, the outside air temperature or the temperature in the storage tank 24.

  As a control system of the exhaust gas purification device, a control unit 32 having a built-in computer is provided to control the injection supply amount of the urea aqueous solution according to the engine operating state. In the control unit 32, based on the signals from the rotational speed sensor 34 for detecting the engine rotational speed Ne and the load sensor 36 for detecting the engine load Q, the reducing agent is controlled by a control program stored in a ROM (Read Only Memory). The supply device 28 is controlled. Here, as the engine load Q, a fuel injection amount, an intake flow rate, an intake negative pressure, an accelerator opening, a throttle valve opening, and the like can be used.

In such an exhaust purification device, the urea aqueous solution supplied by injection from the injection nozzle 18 is hydrolyzed by exhaust heat and water vapor in the exhaust, and ammonia is generated. It is known that the generated ammonia reacts with NOx in the exhaust gas in the NOx reduction catalyst 20 and is purified to water and harmless gas. At this time, in order to improve the NOx purification rate by the NOx reduction catalyst 20, NO is oxidized to NO ₂ by the oxidation catalyst 16, and the ratio of NO and NO ₂ in the exhaust gas is improved to be suitable for the catalytic reduction reaction. The Further, since the ammonia that has passed through the NOx reduction catalyst 20 is oxidized by the ammonia oxidation catalyst 22 disposed downstream of the exhaust gas, it is possible to prevent ammonia that emits a strange odor from being discharged into the atmosphere as it is.

  As shown in FIG. 2, the heater-equipped pipes 26 and 30 are each provided with a cord-like heater 40 and a lead wire 42 along substantially the entire length of a nylon tube 38 for transferring a urea aqueous solution as a fluid. Around the unit, a soaking layer 44 made of aluminum, a heat insulating layer 46 made of glass fiber, a moisture-proof layer 48 made of polyester, and a protective cover 50 made of polyvinyl chloride are sequentially arranged. Here, the soaking layer 44 exhibits a function of transmitting the amount of heat generated by the cord-like heater 40 substantially uniformly to the outer periphery of the nylon tube 38. The tube for transferring the urea aqueous solution is not limited to the nylon tube 38, and a fluorinated resin tube or the like may be used.

  On the other hand, around the both ends of the nylon tube 38, instead of the heat insulating layer 46, the moisture proof layer 48 and the protective cover 50 which are peeled off when the connector 52 as the counterpart device is connected, it is made of a substantially cylindrical silicon sponge or the like. A terminal heat insulating material 54 as a heat insulating layer is disposed, and the heat shrinkable tube 56 is covered over substantially the entire length. Further, the cord-like heater 40 positioned between the nylon tube 38 and the terminal heat insulating material 54 is doubled at a predetermined length in order to double the partial heat generation amount. Specifically, as shown in FIG. 3 (A), a predetermined length L of the end of the cord-like heater 40 is turned back, or as shown in FIG. By connecting a cord-shaped heater 60 having a predetermined length L to the end of the heater 40, a portion having a predetermined length is duplicated. Here, in the case where the crimp terminal 58 shown in FIG. 5B is used, the present invention can be applied even if the cord-like heater 40 has low flexibility and cannot be folded back. In addition, the crimp terminal 62 located in the approximate center in the figure is for connecting the cord-shaped heater 40 and the lead wire 42. Further, the end of the cord-like heater 40 is not limited to a double configuration, and may be folded and multiplexed, for example.

  In this way, since the cord-like heater 40 is duplicated at the ends of the heater-equipped pipes 26 and 30, when the same current is applied, the amount of heat generated at that portion is approximately doubled. While keeping the power consumption as low as possible, the heat retaining and thawing performance of the end can be improved. If the predetermined length L to be duplicated is appropriately set according to the heater capacity, applied current, etc. of the cord-like heater 40, a substantially uniform heat retaining and thawing capability can be exhibited over the entire length of the heater-equipped pipe. The aqueous urea solution transferred by the nylon tube 38 can be effectively kept warm and thawed.

Next, a soaking layer 44, a heat retaining layer 46, a moisture proof layer 48, and a protective cover 50 were sequentially disposed around the cord-like heater 40 and the lead wire 42 disposed along substantially the entire length of the nylon tube 38. A procedure for connecting the connector 52 as the counterpart device to the end portion of the pipe with the heater whose end portion is not cut will be described.
First, the protective cover 50, the moisture-proof layer 48, the heat retaining layer 46, and the soaking layer 44 are cut at appropriate positions from the end of the pipe with heater, and as shown in FIG. The nylon tube 38, the cord-shaped heater 40, and the lead wire 42 are exposed by peeling off. Next, the nylon tube 38 is gripped with a tool (not shown), and the connector 52 is press-fitted into the end portion thereof as shown in FIG. When the connector 52 is press-fitted into the end of the nylon tube 38, the exposed length L of the cord-like heater 40 is doubled and the end and the lead wire 42 are crimped as shown in FIG. After connecting with the terminal 62, the soaking layer 44 made of aluminum tape or the like is wound around the nylon tube 38 and the cord-like heater 40, and then a substantially cylindrical terminal heat insulating material 54 having a slit formed in the axial direction is attached. When the terminal heat insulating material 54 is attached, as shown in FIG. 3D, after covering the heat insulating tube 56 over substantially the entire length of the terminal heat insulating material 54, heat is applied to the terminal heat insulating material 54 so as to shrink it. As shown to E), the circumference | surroundings of the terminal heat insulating material 54 are coat | covered.

  In this way, the heater-equipped pipe is connected to the connector 52 after the heat insulation layer 46 located at the end is peeled off, the cord heater 40 is duplicated, and the terminal heat insulation 54 is attached, and the heat shrinkable tube By sequentially carrying out a series of operations of covering the periphery with 56, it is connected to the counterpart device. For this reason, it becomes easy to implement | achieve the piping with a heater which concerns on this invention using the piping with a heater of a general-purpose product, and reduction of a manufacturing cost etc. can be aimed at effectively.

  Needless to say, the heater-equipped piping according to the present invention can be used not only in an exhaust purification device mounted on a vehicle but also in a cold water supply facility, a gas analyzer, and the like.

The block diagram which applied the piping with a heater concerning this invention to the exhaust gas purification device The details of piping with a heater concerning the present invention are shown, (A) is a front sectional view, (B) is a side sectional view. The method of duplexing the cord heater at the pipe end is shown, (A) is an explanatory diagram of a method of folding the cord heater, and (B) is an explanatory diagram of a method using a crimp terminal. The manufacturing method of piping with a heater concerning the present invention is shown, and (A)-(E) are explanatory views of the 1st process-the 5th process, respectively. The structure of the piping with a heater in a prior art is shown, (A) is a cross-sectional view, (B) is a perspective view.

Explanation of symbols

26 Piping with heater 30 Piping with heater 38 Nylon tube 40 Corded heater 42 Lead wire 44 Heat equalizing layer 46 Insulating layer 52 Connector 54 Terminal heat insulating material 56 Heat shrinkable tube 58 Crimp terminal 60 Corded heater 62 Crimped terminal

Claims (7)

Piping for transferring fluids;
A cord-shaped heater disposed along substantially the entire length of the pipe;
A heat insulating layer disposed around the pipe and the heater;
In a pipe with a heater configured to include
The heater located at the end of the pipe is connected to a cord-like heater at the end so that a portion having a predetermined length is multiplexed.   2. The piping with a heater according to claim 1, wherein a soaking layer is provided between the piping and the heater and the heat insulating layer to transmit a heat amount generated by the heater to the outer periphery of the piping substantially uniformly.   When a cord-shaped heater is disposed along substantially the entire length of the pipe for transferring the fluid, and the pipe with a heater in which at least a heat insulating layer is disposed around the pipe and the heater, Strip the insulation layer from the end to expose part of the piping and heater, connect the end of the piping to the counterpart device, multiplex the exposed heaters, and expose the exposed piping and heaters. A method for connecting a pipe with a heater, characterized by disposing a heat insulating layer around the heater.   When a cord-shaped heater is disposed along substantially the entire length of the pipe for transferring the fluid, and the pipe with a heater in which at least a heat insulating layer is disposed around the pipe and the heater, Strip the insulation layer from the end to expose part of the piping and heater, connect the end of the piping to the counterpart device, multiplex the exposed heaters, and expose the exposed piping and heaters. A method for connecting a pipe with a heater, characterized by disposing a soaking layer and a heat insulating layer around the heater.   The method for connecting a pipe with a heater according to claim 3 or 4, wherein the heat insulating layer is further covered with a heat shrinkable tube.   The connecting method of piping with a heater according to any one of claims 3 to 5, wherein the heaters are multiplexed by folding back end portions thereof.   6. The method for connecting pipes with a heater according to claim 3, wherein the heaters are multiplexed by connecting a cord-like heater at an end thereof.

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