GB2176239A - Exhaust muffler - Google Patents

Abstract

In an exhaust muffler the sheet metal walls of an enclosure 12 are coated on their internal faces with a layer 18 of a plastics material resistant to corrosion from the condensates likely to collect in the muffler. Baffles inside the muffler may also be coated with corrosion resistant plastics material. <IMAGE>

Description

SPECIFICATION Exhaust muffler This invention relates to an exhaust muffler for use in muffling or silencing the exhaust of an internal combustion engine.

Exhaust mufflers are boxes containing baffles and/or sound deadening material, and are located in an exhaust pipe somewhere between the engine and the downstream end of the pipe. Mufflers unfortunately tend to collect liquid condensates from the exhaust gases, and these condensates are highly corrosive, resulting in undesirable corrosion damage to the muffler.

According to the present invention, there is provided an exhaust muffler comprising an enclosure having walls of sheet metal, an exhaust gas inlet to the enclosure and an exhaust gas outlet therefrom and noise muffling components inside, wherein the sheet metal walls are coated on their internal faces with a layer of a plastics material resistant to corrosion from the condensates likely to collect in the muffler.

If the muffler is mechanically assembled, using a lockseam construction, the sheet metal can be coated with a suitable plastics material before assembly.

Accordingly, the invention also provides a method of making a muffler from sheet metal, which comprises coating at least one face of the sheet metal with a layer of a corrosion resistant plastics material, and subsequently assembling the muffler from the coated sheet metal with the plastics coated face on the inside of the muffler.

Sheet steel used in muffler construction is frequently supplied to the muffler manufacturer with a protective plastics coating. It is normal practice to remove this coating before forming the steel into mufflers, but according to this invention, the protective plastics coating can be left in place.

It may be furthermore be desirable to coat internal components of the muffler, such as baffles, with a layer of corrosion resistant plastics material.

The invention will now be further described, by way of example, with reference to the accompanying drawing which is a cross-section through a muffler in accordance with the invention.

The figure shows a portion of an exhaust pipe 10 including a muffler box 12, an intermediate pipe 14 leading into the box 12 and a tail pipe 16 leading out of the box. The internal walls of the box are lined with a layer 18 of a suitable plastics material.

This lining of the internal box walls can substantially improve the resistance of the muffler to corrosion caused by corrosive substances collecting inside.

1. An exhaust muffler comprising an enclosure having walls of sheet metal, an exhaust gas inlet to the enclosure and an exhaust gas outlet therefrom and noise muffling components inside, wherein the sheet metal walls are coated on their internal faces with a layer of a plastics material resistant to corrosion from the condensates likely to collect in the muffler.

2. An exhaust muffler as claimed in claim 1, wherein the muffler is mechanically assembled, using a lockseam construction, and the sheet metal is coated with a suitable plastics material before assembly.

3. An exhaust muffler as claimed in claim 1 or 2, wherein internal components of the muffler, such as baffles, are also coated with a layer of corrosion resistant plasctics material.

4. A method of making a muffler from sheet metal, which comprises coating at least one face of the sheet metal with a layer of a corrosion resistant plastics material, and subsequently assembling the muffler from the coated sheet metal with the plastics coated face on the inside of the muffler.

5. An exhaust muffler constructed substantially as herein described with reference to and as illustrated in the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Exhaust muffler This invention relates to an exhaust muffler for use in muffling or silencing the exhaust of an internal combustion engine. Exhaust mufflers are boxes containing baffles and/or sound deadening material, and are located in an exhaust pipe somewhere between the engine and the downstream end of the pipe. Mufflers unfortunately tend to collect liquid condensates from the exhaust gases, and these condensates are highly corrosive, resulting in undesirable corrosion damage to the muffler. According to the present invention, there is provided an exhaust muffler comprising an enclosure having walls of sheet metal, an exhaust gas inlet to the enclosure and an exhaust gas outlet therefrom and noise muffling components inside, wherein the sheet metal walls are coated on their internal faces with a layer of a plastics material resistant to corrosion from the condensates likely to collect in the muffler. If the muffler is mechanically assembled, using a lockseam construction, the sheet metal can be coated with a suitable plastics material before assembly. Accordingly, the invention also provides a method of making a muffler from sheet metal, which comprises coating at least one face of the sheet metal with a layer of a corrosion resistant plastics material, and subsequently assembling the muffler from the coated sheet metal with the plastics coated face on the inside of the muffler. Sheet steel used in muffler construction is frequently supplied to the muffler manufacturer with a protective plastics coating. It is normal practice to remove this coating before forming the steel into mufflers, but according to this invention, the protective plastics coating can be left in place. It may be furthermore be desirable to coat internal components of the muffler, such as baffles, with a layer of corrosion resistant plastics material. The invention will now be further described, by way of example, with reference to the accompanying drawing which is a cross-section through a muffler in accordance with the invention. The figure shows a portion of an exhaust pipe 10 including a muffler box 12, an intermediate pipe 14 leading into the box 12 and a tail pipe 16 leading out of the box. The internal walls of the box are lined with a layer 18 of a suitable plastics material. This lining of the internal box walls can substantially improve the resistance of the muffler to corrosion caused by corrosive substances collecting inside. CLAIMS

1. An exhaust muffler comprising an enclosure having walls of sheet metal, an exhaust gas inlet to the enclosure and an exhaust gas outlet therefrom and noise muffling components inside, wherein the sheet metal walls are coated on their internal faces with a layer of a plastics material resistant to corrosion from the condensates likely to collect in the muffler.

2. An exhaust muffler as claimed in claim 1, wherein the muffler is mechanically assembled, using a lockseam construction, and the sheet metal is coated with a suitable plastics material before assembly.

3. An exhaust muffler as claimed in claim 1 or 2, wherein internal components of the muffler, such as baffles, are also coated with a layer of corrosion resistant plasctics material.

4. A method of making a muffler from sheet metal, which comprises coating at least one face of the sheet metal with a layer of a corrosion resistant plastics material, and subsequently assembling the muffler from the coated sheet metal with the plastics coated face on the inside of the muffler.

5. An exhaust muffler constructed substantially as herein described with reference to and as illustrated in the accompanying drawing.