GB2127093A

GB2127093A - Packing automobile exhaust silencer casing

Info

Publication number: GB2127093A
Application number: GB08225865A
Authority: GB
Inventors: Norman Robinson
Original assignee: Unipart Group Ltd
Current assignee: Unipart Group Ltd
Priority date: 1982-09-10
Filing date: 1982-09-10
Publication date: 1984-04-04
Also published as: CA1240131A; EP0106481B1; GB2127093B; DE3369360D1; EP0106481A3; EP0106481A2; JPS59131717A

Abstract

Vacuum producing apparatus 2 is brought into contact with one end of the silencer casing 1, stub pipe 7 registering with the perforated tube 6, and a similar sealing member 9 having an aperture 10 is brought into contact with the open end of the silencer casing, thereby blocking off the other end of the perforated tube 6. A strand or roving consisting of a multitude, for example, two thousand continuous glass fibres of diameter, for example, less than twenty microns, is fed between two rollers, (12, 13), Fig. 2 (not shown), one of which is driven, in gun 4 where a further roller (15) having a cutter (14) cuts the roving into discrete lengths. An air blast assists in projecting the discrete lengths forwards, and they are sucked into the silencer casing by means of the vacuum. <IMAGE>

Description

1 GB 2 127 093 A 1

SPECIFICATION

Packing automobile exhaust silencers This invention relates to the packing of automobile 70 exhaust silencers.

Such silencers contain packing in order to assist in silencing exhaust gases from the vehicle engine by virtue of conversion of kinetic energy of the exhaust gases into mechanical displacements of the packing and thus heating thereof.

One of the materials used to pack such silencers is glass fibre fluffed up into a wool-like consistency.

This material can be produced by chopping con tinuous strands of glass fibre.

In the past such silencers have been packed with such material manually and, to assist in this process, it has been proposed to apply a vacuum to one end of the silencer casing.

In order to adapt the process for automatic 85 operation, glass fibre material in wool-like form has been fed into a hopper, from which it passes along ducts before being metered into individual quanti ties, each suitable for packing one silencer. However, the material has been prone to clog in the ducts and this has made the accurate metering of the material difficult, if the expense of weigh pans is to be avoided.

The inventjion provides a method of packing a silencer casing which comprises applying a vacuum to one end of a silencer casing, chopping into discrete lengths a strand consisting of a plurality of continuous glass fibres and allowing them to enter the other end of the silencer casing.

It has been found that the individual fibres of each discrete length of strand can separate as they are being sucked into the silencer so that the packing fluffs up in the desired way in the silencer casing itself or as it is entering.

The strand, or roving, advantageously contains at 105 least an hundred, preferably at least a thousand, individual continuous glass fibres whose diameter is advantageously less than 30 microns and preferably less that 15 microns. The fibres of the roving are preferably non-twisted.

Advantageously the roving is driven from two rollers in contact with each other; this makes it easy to meter acurate quantities of glass fibre into each silencer casing, since it is only necessary to leave the rollers running for a certain period of time in order to know exactly how much glass fibre has been fed into the silencer. A roller may also be provided for chopping the fibres, and they may be projected with the assistance of an air blast.

The vacuum applied to the silencer casing may be at least one inch of mercury, preferably at least five inches of mercury, and advantageously between seven and a half and twelve and a half inches of mercury.

The invention also provides a silencer casing 125 packed in accordance with any of the forms of the method of the invention.

A method of, and apparatus for, packing a silencer casing in accordance with the invention will now be described byway of example with reference to the accompanying drawings in which:

Figure 1 is a partly sectional view of the apparatus; Figure 2 is a side view of a gun for feeding the roving into the silencer; Figure 3 is a front view of the gun shown in Figure 2; and Figure 4 is a plan view of the gun shown in Figure 2.

Referring to Figure 1, apparatus for packing a silencer casing 1 comprises a vacuum producing apparatus 2, a sealing apparatus 3 and a gun 4.

The casing of the silencer is circular in section, and one end of it has been closed by an end piece 5, which supports a perforated tube 6 running along the length of the silencer casing. The end piece 5 supports a stub pipe 7 which connects to the rest of the exhaust assembly in use. A similar end piece bearing a stub pipe is welded to the other end of the silencer when it has been packed.

The vacuum producing apparatus has a rubber sealing member 8 which fits tightly around the stub pipe 7. The vacuum is produced by means of a centrifugal compressor (not shown) driven by a forty horse power motor (not shown). This apparatus produces a vacuum of around ten inches of mercury.

The sealing apparatus 3 likewise includes a sealing member 9 which seals against the open end of the casing and also blocks off the open end of the perforated tube 6, since this must not be filled with any packing material. The sealing member has an arcuate slot-like apperture 10, whose arcuate length is around four times its diameter.

Referring to Figure 2, the roving fed into the gun 4 consists of around two thousand mono-filamentary continuous glass fibres, whose diameters lie between about six and twelve microns. The fibres in the roving are parallel to each other, that is, the roving is not twisted. The roving is fed from a spool (not shown) containing a length of about a couple of hundred meters of the roving.

The gun has an air-powered motor, contained in housing 11, to which rubber roller 12 is coaxially attached. The roving is driven by means of rubber roller 12 and steel roller 13 which is hard in contact with roller 12. The roving is cut into discrete lengths by means of a cutter 14 mounted diametrically through a further roller 15. Every half revolution of roller 15, the roving is severed at the point of contact with roller 12. The rollers are contained in a housing 16 having an inlet 17 and an outlet 18. The air exhaust from the air- powered motor is fed into the housing 16 and, since the area of the outlet 18 is much greater than that of the inlet 17, the chopped lengths of roving are projected out of the gun with the aid of an air blast.

In operation of the method of the invention, a silencer casing 1 to be filled is fitted onto the vacuum producing apparatus 2 and a sealing apparatus is brought up to the open end of the silencer. The vacuum pump is started. The gun 4 is then run and left running for a pre-determined period of time. This pre-determined period corresponds to the desired weight of glass fibre it is desired to pack the particular silencer with, and this can be calculated simply from the weight per unit length of the roving 2 GB 2 127 093 A 2 and the velocity at which the roving is fed through the gun.

The chopped lengths of roving projected from the gun are all sucked through the apperture 10 in the sealing member 9 because of the vacuum applied at the other end of the silencer casing, and the silencer is gradually filled with glass fibre. It has been found thatthe fibres of each chopped length of roving separate either before they enter the silencer casing or while they are in the silencer casing (probably the 75 separation mainly takes place within the silencer), and this results in the production of the desired wool-like form of the glass fibre in the silencer. The air flow within the silencer will of course be turbulent since it us being sucked through the perforated tube 6. The lengths of fibre do not pass into the tube 6 themselves.

Amoung the advantages of the invention are that it is possible to accurately meter the quantities of glass fibre with which each silencer is packed, and that the ducting required for handling the wool-like glass fibre is dispensed with.

The invention is of course applicable to any form of silencer, for example, such as the form where exhaust gases make multiple passes of the whole the part of the length of the silencer casing.

Claims

1. A method of packing an automobile exhaust silencer casing, which comprises applying a vacuum to one end of the silencer casing, and chopping into discrete lengths a strand consisting of a plurality of continuous glass fibres and allowing them to enter the other end of the silencer casing.

2. A method as claimed in claim 1, in which the strand consists of at least one hundred continuous glass fibres.

3. A method as claimed in claim 2, in which the strand consists of at least a thousand glass fibres.

4. Amethodasclaimed in anyoneof claims 1 to 3, in which the diameters of the fibres of the strand are less than thirty microns.

5. A method as claimed in claim 4, in which the diameters of the continuous glass fibres of the strand are less than fifteen microns.

6. Amethod as claimed in anyone of claims 1 to 5, in which the continuous glass fibres of the strand are not twisted.

7. A method asclaimed in anyone of claims 1 to 6, in which the vacuum is at least one inch of mercury.

8. A method as claimed in claim 7, in which the vacuum is at least five inches of mercury.

9. A method as claimed in claim 8, in which the vacuum lies between seven and a half and twelve and a half inches of mercury.

10. A method as claimed in anyone of claims 1 to 9, in which the strand is fed between two rollers engaging one another, one of which is driven.

11. A method as claimed in claim 10, in which the strand passes between a pair of rollers, one of which has a cutter running along a generator of the roller.

12. A method as claimed in claim 10 orclaim 11, in which the discrete lengths are projected with the assistance of an air blast.

13. A method of packing an automobile vehicle silencer casing substantially as hereinbefore described with reference to the accompanying draw- ings.

14. A silencer casing packed according to the method of any one of claims 1 to 13.

15. An automobile exhaust system having a silencer as claimed in claim 14.

16. Apparatus for packing an automobile exhaust silencer casing which comprises means for applying a vacuum to one end of a silencer casing and means for chopping into discrete lengths a strand consisting of a plurality of continuous glass fibres which are allowed to enter the other end of the silencer casing.

Printed for Her Majesty's Stationery Office, by Croydon Printing Company Limited, Croydon, Surrey, 1984. Published by The Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.