JP4201754B2 - Heater parts for piping joints - Google Patents

Description

  The present invention relates to a heater structure for a joint that connects pipes and pipes, or pipes and equipment, and more particularly, to a heater that performs heat insulation and defrosting on a joint part of a pipe in an exhaust purification device of an internal combustion engine.

  Recently, a selective catalytic reduction (SCR) device using a liquid reducing agent such as urea water has been proposed as an exhaust gas purification device for purifying nitrogen oxide (NOx) contained in exhaust gas from a diesel engine. This apparatus employs a configuration in which a liquid reducing agent is added to the exhaust passage upstream of the nitrogen oxide reduction catalyst in order to increase the purification efficiency of the nitrogen oxide reduction catalyst interposed in the exhaust passage. However, when urea water is used as the liquid reducing agent, it freezes at a relatively high predetermined temperature, so it is necessary to take measures against freezing of the piping.

Structures in which piping is insulated with a heat insulating material or heated with a heater are widely used in fields such as water supply piping and factory equipment. In these cases, joints (connectors, flanges) for connecting other devices and piping to each other For example, as shown in FIG. 5 and FIG. 6 of Patent Document 1, the part is dealt with by covering it with a heat insulating material separately from the pipe body or winding a heater.
JP-A-4-102793

However, the above-described conventional technique is a method based on the premise of manual work, which is time-consuming and difficult to stabilize the assembly quality due to individual differences among workers. Further, since the entire joint portion is covered separately from the piping portion, it is bulky and is not suitable for the piping of an exhaust purification device having a small installation space.
On the other hand, there is an example in which a connector with a heater is used as a joint in the engine blow-by gas piping, but since the connector becomes a dedicated product, there is a problem that the mold cost increases when the production amount is small. .

In view of such a technical background, the present invention proposes a heater component for a pipe joint that can be attached to a joint more easily than before and can stabilize its assembly quality.
In addition, we propose a heater component for piping joints that can be installed retrofitting to a ready-made joint instead of a dedicated product, and can reduce costs such as mold costs.

The heater component for a pipe joint according to the present invention partially has a fitting portion having an inner surface shape that fits a part of the outer shape of the joint provided on the outer periphery of the joint, and a heater on the inner surface portion inside the fitting portion. A holding recess for holding the wire is formed, and when the fitting is fitted to the joint from outside, the heater wire held in the holding recess comes into contact with the joint and energizes the heater wire to heat the heater wire. Is conducted to the joint.

Since this pipe joint heater part is merely fitted to the joint from the outside, it is not bulky and can be attached to the joint very easily. And unlike conventional manual work, it can be installed by simply fitting the uniform heater parts to the joint, so that the assembly quality can be stabilized regardless of skill and experience. In addition, instead of creating a dedicated joint with a built-in heater, heater parts can be made as fittings to ready-made joints, so it can be attached to a joint that has already been assembled, The mold cost is also much lower than when a dedicated joint is manufactured. Because of these advantages, the heater component for a pipe joint according to the present invention includes a nitrogen oxide reduction catalyst in the exhaust passage of the internal combustion engine and a liquid in the exhaust passage upstream of the nitrogen oxide reduction catalyst. It is particularly suitable as a heater component for a pipe joint in an exhaust purification apparatus to which a reducing agent is added.
For such a pipe joint heater component, as a concrete structure that is easy to produce, a heater wire is provided on the inner surface portion other than the fitting portion, while partially having a fitting portion having an inner shape that fits a part of the outer shape of the joint. forming a holding recess for holding, by said heater wire is held in the holding recess has an abutting structure the joint, the heater wire can the system be fitted into the holding recess later, the body portion of the resin injection molding Can be created easily. Moreover, since a heater wire contacts a joint directly, the thermal conductivity to a joint will increase.

Further, it is preferable that a partial convex portion is formed on the bottom surface in the holding concave portion and an air layer is provided between the held heater wire and the bottom surface. This air layer functions as a heat insulating layer and improves thermal efficiency. Further, the heater wire in the holding recess which holds the heater wire is in part a different part of contact with the joint, it may be provided with a lid member for preventing the falling off of the heater wire. If the lid member is made of a heat insulating material having a good heat insulating property, the thermal efficiency can be further increased.

  In such a heater component for pipe joints, it is preferable to form an inclined guide for bending the lead portion of the heater wire extended to the outside so as to bend outward in the pipe radial direction. That is, when the insulation material is wound around the pipe and has a larger diameter than the joint, the heater wire lead portions extended from the heater parts are gathered together with the inclined guides and guided radially outward. It makes it easy and prevents disconnection.

  According to the heater component for a pipe joint of the present invention, it can be mounted with a simple work just by fitting it to a ready-made joint, and the assembly quality is stabilized without being influenced by individual differences such as experience by omitting manual work. be able to. And since it is not bulky as compared with a conventional structure in which a heat insulating material or a heater is wound manually, it is suitable for piping of an exhaust purification device having a small installation space. Furthermore, it can be retrofitted to a ready-made joint, and costs such as mold costs can be reduced compared with the case of producing a dedicated joint with a heater.

  In addition, in the piping structure of the exhaust gas purification device using a liquid reducing agent, heating of the joint portion can be performed reliably, and heating can be performed uniformly without generating defective locations of heat insulation and thawing in the entire length of the piping. it can. In such a pipe structure of the exhaust purification device, a method of increasing the heater wattage of the pipe part for heating the joint part without providing a heater in the joint part is also taken. Thus, the power consumption can be reduced as compared with the method of increasing the total wattage at the time of heat insulation and thawing, and the time required for heat insulation and thawing can be shortened when the wattage is the same. That is, useless power consumption can be eliminated for a limited generator capacity.

1 to 6 show a preferred embodiment of the present invention. 1 is an exploded perspective view of the pipe joint heater part 1 and the joint 10, FIG. 2 is a plan view of the pipe joint heater part 1 holding the heater wire H, and FIG. 3 is a sectional view thereof. 4 and 5 are plan views of the pipe joint heater component 1 with the heater wire H removed, FIG. 5 is a sectional view thereof, and FIG. 6 is an overall view of the heater wire.
The heater part 1 for a pipe joint in this example is mounted on an elbow-type joint 10 that connects two pipes K1 and K2 at 90 °, is a resin molded product, and is fitted to a part of the joint outer shape. There are two fitting portions 2 having an inner surface shape, and holding recesses 3 are formed on the inner surface portion other than the fitting portion 2. The holding recess 3 has a partial convex portion 5 formed on the bottom surface 4, and the heater wire H is placed on the partial convex portion 5 so that a space is formed between the holding concave portion 3 and the bottom surface 4. It is a layer.

The heater wire H is routed and held in a U-shape in the holding recess 3, and lead portions L at both ends thereof are extended from the heater component 1 and are electrically wired to the coupler C via the resistor R. E is connected. The heater wire H is appropriately controlled according to the outside air temperature, the temperature in the tank of the liquid reducing agent, or the like, for example, by a control unit of the exhaust purification device.
The joint 10 is attached to the first pipe K1, and connects the second pipe K2 provided at 90 ° to the first pipe K1. A flange F is provided around the mouth portion of the second pipe K2, and the joint 10 is provided with two claw portions 11 for locking the flange F at 180 ° intervals on the outer periphery. Therefore, when the second pipe K2 is inserted into the joint 10, the flange F is locked to the claw portions 11 at the two locations, so that the disconnection is prevented and fixed. Further, in the case of this example, a lock release button 12 is provided, and when the lock release button 12 is pushed in, the claw portion 11 is expanded to release the lock, and the second pipe K2 can be pulled out. It can be done.

  The two fitting portions 2 of the pipe joint heater component 1 are formed in an inner surface shape that fits into the claw portions 11 provided on the outer periphery of the joint 10. Accordingly, the pipe joint heater component 1 in which the heater wire H is held in the holding recess 3 can be easily attached simply by covering the joint 10 so that the fitting portion 2 is fitted to the claw portion 11. After the attachment, when the clip 6 is inserted into the insertion hole 7 and penetrated, the clip 6 enters and locks inside the claw portion 11 of the joint 10, thereby preventing the dropping more reliably. ing.

  In this example, the stainless steel lid member 8 is attached so as to partially cover the holding recess 3 so that the heater wire 3 held in the holding recess 3 can be prevented from falling off. That is, the two locking pieces 8 a protruding from the side portion of the lid member 8 are fixed by being locked in the locking holes 9 opened in the side wall forming the holding recess 3. The lid member 8 serves to cover the U-shaped bent portion of the heater wire H that does not come into contact with the joint 10 to prevent the lid from falling off, and at the same time, reduces the escape of heat of the portion to the outside, thereby improving thermal efficiency. Have a role to enhance. For this role, a material having a higher heat insulating effect, such as glass or ceramics, may be used.

  Further, the pipe joint heater component 1 of the present example is an inclined guide 1G for causing the lead part L of the heater wire H to be bent outwardly in the radial direction of the first pipe K1. Is formed. The inclined guide 1G warps the lead portion L of the heater wire H outward in the pipe radial direction when a heat insulating material (not shown) is wound around the first pipe K1 and is thicker than the joint 10. In addition, the lead portions L are guided and gathered to facilitate handling, and at the same time, there is an effect of preventing disconnection due to sudden bending at the end of the heater component. A semicircular guide groove m for holding the lead portion L is formed on the inner surface portion of the inclined guide 1G, and the holdability is improved.

  In assembling the pipe joint heater component 1 having the above configuration, first, the heater wire H is held in a U-shape in the holding recess 3 and held. At this time, the heater wire H is placed on the partial convex portion 5 and an air layer is formed between the heater wire H and the bottom surface 4. Then, the lid member 8 is locked to the locking hole 9 and attached to prevent the dropping, and the fitting portion 2 is fitted to the claw portion 11 of the fitting 10 so that the fitting 10 is connected to the pipe fitting. The heater part 1 is covered, and the clip 6 is inserted into the insertion hole 7 and fixed. In this state, a portion of the heater wire H supported by the partial protrusion 5 abuts on the joint 10, and when the heater wire H is energized, the heat is directly conducted to the joint 10.

In this mounting operation, even when a heat insulating material is wound around the first pipe K1 and becomes thick, the lead portion L of the heater wire H is guided by the inclined guide 1G, so it is gathered together and easy to handle. At the same time, the possibility of disconnection is reduced.
In the above, an example of a pipe joint heater component for a joint that connects two pipes at 90 ° has been described. However, the present invention is not limited to this, but a joint that connects at 180 ° or other angles, or three, four Naturally, the present invention can be applied even to a joint connecting pipes.

The perspective view showing the embodiment of the present invention. The top view of the heater component for piping joints of FIG. Sectional drawing of the heater component for piping joints of FIG. The top view which showed the heater component for piping joints of FIG. Sectional drawing of the heater component for piping joints of FIG. The top view which showed the whole heater wire.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heater part for piping joints 1G Inclination guide m Guide groove 2 Fitting part 3 Holding recessed part 4 Bottom face (holding recessed part)
5 Partial convex part 6 Clip 7 Insertion hole 8 Lid member 8a Locking piece 9 Locking hole 10 Joint 11 Claw part 12 Lock release button C Coupler E Electrical wiring H Heater wires K1, K2 Piping L Lead part R Resistance

Claims (5)

A holding recess for holding the heater wire is formed on the inner surface portion inside the fitting portion and partially having a fitting portion of the inner shape that fits a part of the outer shape of the joint provided on the outer periphery of the joint,
When fitted and fitted to the joint from the outside, the heater wire held in the holding recess comes into contact with the joint,
Heating of the heater wire is conducted to the joint by energizing the heater wire. A pipe joint heater component. The bottom surface of the holding recess to form a partially protruding portion, the pipe fitting heater component of claim 1, wherein the provision of the air layer between the bottom and the heater wire held in said holding recess. 3. The piping according to claim 1, further comprising: a lid member that prevents the heater wire from falling off at a portion different from a portion where the heater wire contacts the joint in the holding recess holding the heater wire. Heater parts for joints. The pipe joint heater component according to claim 3, wherein the lid member is made of a heat insulating material. The pipe joint heater according to any one of claims 1 to 4 , wherein an inclined guide is formed for bending the lead portion of the heater wire so as to bend outward in the pipe radial direction. parts.