Background of the Invention
This invention relates to an exhaust system pipe, particularly for a tractor, for connection to a second pipe by receiving an end portion of the second pipe therein.
Exhaust system pipes of tractors are usually connected simply by fitting the end of one pipe into an end of the other pipe, the overlapping end portions of the pipes contacting each other. In damp and hot conditions, met within service, the pipes tend to corrode and to adhere fairly strongly, one to the other, so that when one of the pipes is to be replaced, it is often difficult to free them.
Summary of the Invention
The present invention provides a design of pipe in which the contact area between two connected pipes is greatly reduced so that they can be freed more easily from one another for replacement.
According to the present invention, an exhaust system pipe for connection to a second pipe by receiving an end portion of the second pipe therein has an insert therein with a converging portion for providing a seat for a converging end of the said end portion and an inward protrusion spaced from the insert for contacting the outer surface of the second pipe to maintain the second pipe out of contact with the inner surface of the first pipe, except at the protrusion and the insert.
The invention includes an exhaust system, including a said exhaust system pipe connected to a said second pipe.
Brief Description of the Drawing
The FIGURE is a diagrammatic longitudinal cross-sectional view through a portion of an exhaust pipe system constructed according to the applicant's invention.
Detailed Description of the Invention
A muffler 10 of the exhaust system is located below the hood (or bonnet) of a tractor which is not shown in the drawing. The muffler 10 has a vertical outlet pipe 12 which projects through an aperture in the hood, and in the present case, the upper end portion 14 of the pipe 12 is frusto-conical in shape. The muffler 10 is of standard construction, except that it includes a pair of upright external flanges, of which one only is shown and designated 16. Each flange 16 consists of two flange portions, which in the standard construction would be within the muffler welded together during its fabrication.
A vertical end pipe 18 is provided which includes an insert 20 which is welded at least at its upper end to the inner surface of the pipe 18 and which consists of an upper frusto-conical portion 22 converging toward outlet pipe 12 and a lower frusto-conical portion 24 converging away from outlet pipe 12 but with a different inclination to the upper end portion 14 of the outlet pipe 12.
The end pipe 18 has a constant diameter throughout its length except that there is a slight increase in diameter due to the provision of a shoulder 26 at the lower end portion of the pipe. Seating against this shoulder 26 is a steel ring 28 of which the radially outer surface follows the contour of a cylinder and the radially inner surface is convex in cross-section. The ring 28 is located, again, by welding.
Finally, two diametrically opposite blind slots, of which one only, 30, is shown, extend parallel to the axis of the pipe 18 from the pipe's bottom edge. These slots are in alignment to receive corresponding flanges 16.
To connect the end pipe 18 to the muffler outlet pipe 12, all that is necessary is that the lower end of the end pipe 18 is fitted over the outlet pipe 12 with the slots 30 aligned with the flanges 16, and then pushed downwardly until the flanges 16 are received by the slots 30 and the upper end portion 14 of the outlet pipe 12 comes into abutment with the lower frusto-conical portion 24 of the insert 20. The exhaust system is then ready for use.
It will be appreciated that the areas of contact between the insert 20 and the outlet pipe 12 and between the ring 28 and the pipe 12 are very small. During service, the exhaust system is, as mentioned above, subject to damp and hot conditions which encourage the formation of rust at the contacting surfaces and which tend to make the surfaces adhere one to the other. However, since the areas of contact are so small, it is normally an easy task to free the end pipe 18 from the outlet pipe for replacement when this becomes necessary. If the end pipe were permitted to turn in relation to the outlet pipe 12, wear could result and a weather cap (not shown) could become disoriented. The weather cap is usually mounted at the top end of the end pipe 18. However turning is prevented by the seating of the flanges 16 in the slots 30.
Furthermore, the downwardly converging portion 22 of the insert 20 assists exhaust gas flow in that its shape causes deceleration of the upward flow of exhaust gas, reducing back pressure and gas tightness.