US2516948A

US2516948A - Water-cooled silencer

Info

Publication number: US2516948A
Application number: US734113A
Authority: US
Inventors: Roland B Bourne
Original assignee: Maxim Silencer Co
Current assignee: Maxim Silencer Co
Priority date: 1947-03-12
Filing date: 1947-03-12
Publication date: 1950-08-01
Anticipated expiration: 1967-08-01

Description

Aug. 1, 1950 R. B. BOURNE WATER COOLED SILENCER Filed March 12, 1947 INVENTOR Aou/vo 6. 500/?6 BY $744 ATTORNEYS Patented Aug. 1, 1950 WATER-COOLED SILENCER Roland B. Bourne, West Hartford, Conn, assignor to The Maxim Silencer Company, Hartford, Conn., a corporation of Connecticut Application March 12, 1947, Serial No. 734,113 2 Claims. (01. 181-43) This invention relates to silencers for the-exhau'st of internal combustion engines, particularly to such silencers as have cooling water introduced into the exhaust gas stream in such a manner'that water spray and the exhaust gases are'carried through the silencer together. The purpose of the invention is to improve the silencing efficiency of this type of silencer, while using few parts and those of simple construction and light weight. The improved silencer is of particular value for such uses as the silencing of the engines of submarines during surfacing, the silencer being flooded when the submarine submerges. Tests have shown that the silencer constructed in accordance with the present invention will reduce the sound level of the exhaust 10 db below the best of the silencers previously available for the purpose, while at the same time having a size and weight much less than such prior silencers.

The improved silencer operates upon a novel mode of coaction between an acoustic filter and gas-entrained cooling water. In the preferred embodiment the main channel through which the exhaust gas and cooling water flows is coupled to one or more resonance chambers or sidebranches, and is fitted with means causing a substantial portion of the cooling water to be deflected into the sidebranches. The combination of the effect of resonance in the sidebranches and the cooling and sound attenuating action of the water spray greatly increases the silencing efficiency both at high and low frequencies.

The extreme simplicity of the silencer is at once apparent from the drawings, in which Fig. 1 is a median section taken longitudinally through the silencer;

Fig. 2 is a section on line 2-2 of Fig. 1; and

Fig. 3 is a detail plan of the downstream end of the inlet section of the main channel.

The silencer comprises a horizontally disposed cylindrical shell it! having an inlet header I I, an outlet header l2 and an intermediate header l3 dividing the interior of the shell into two chambers l4 and 15. Through the headers H, I2, and I3 pass respectively an inlet conduit IS, an intermediate conduit I1, and an outlet conduit l8. Collectively these conduits form the main gas and sound conducting channel, and the portions of the chambers I l and I5 not occupied by the conduits serve as resonance chambers or sidebranches acoustically and physically coupled to the main channel at the gaps l9 and 20 between the sections of conduit. Preferably these gaps are of a length between 70% and 100% of the diameter of the conduit, and are centered at a point between one-quarter and one-third of the length of the chamber measured from its upstream end. The two chambers are preferably of unequal size to broaden the band of frequencies attenuated by resonance, and their dimensions are chosen to produce maximum attenuation of the major frequencies occurring the exhaust system of the engine to which the silencer is to be fitted. To prevent shock excitation of the intermediate and exhaust conduits the former is pierced with antiresonance holes 2| located at the half and quarter points of the conduit as fully discussed in United States Patent 2,265,342, and the outlet conduit provided with a slot 22 preferably positioned on the bottom of the conduit to assist in drainage of the chamber l5.

The downstream open ends of the conduits l6 and I! are each fitted with a device which will cause water passing with the gas through the conduit to be deflected out into the chambers I4 and I5. This water is preferably supplied to the gas during its passage through the inlet conduit l6 through a series of holes 23 passing through the wall of that conduit into an encircling housing 24 provided with a pipe 25 through which water may be supplied from any desired source. Water enters the conduit simultaneously throughout its circumference and is carried away by the current of exhaust gas in the form of a spray. The deflecting device is preferably in the form of a scoop 26 in the form of half a cone with a apex angle. The deflectors extend about half way across the open end of their associated conduits, and neither their size nor angle is particularly critical. They serve to deflect most of the entrained water into the sidebranches, although some water passes directly into the next conduit section and some more passes out through a hole 21 formed near the apex of the cone which is useful to permit rapid draining of the conduits when the submarine surfaces.

The chambers l4 and 15 are vented to atmosphere through openings 28 so that, upon submerging, these chambers completely fill with water, leaving no entrapped air which might disturb the trim of the vessel. A small opening 29 in the upper portion of the intermediate header l3 also assists in venting. The interior of the silencer is preferably coated with some protective material such as enamel, and by forming the shell In in two parts joined by a gasketed flange 30 the internal parts are made readily accessible for enamelling and at the same time provision is made for holding the intermediate header l3 in place.

What I claim is:

1. A silencer having a substantially cylindrical casing, at least one transverse partition dividing :5

said channel having a gap opening into each chamber intermediate the length thereof, a water inlet delivering water into the channel-sat'aii point prior to the gap in one of the chambers, and a deflector located Within each gap subsequent'to the point of water introduction-comprisinga -half...l5

cone whose axis is substantially coincidentwith that of the channel and WhOSBLhfllfbEliSBHiSJitCOa incident with half of the channel at the upstreamc end of the gap to throw into each chamber the water entrained bythe gas entering said gap.

sound conducting channel positioned substan 2313;614-

tially- -tangent to theinterior of saidcasing at one side 'thereof andpassing-ina" substantially straight line through the'several chambers-said ch'annel having a gap opening intoeach chamber intermediate' -thlength' thereof, "a water "inlet 4 delivering water into the channel at a. point prior to the gap in one of said chambers, and a deflector located within each gap subsequent to the point of water introduction comprising a half cone whose axis is substantially coincident with that of the channel and whose half base is coincident with half of the channel at the upstream end of thex-gap' to throw into each" chambenthezwater entrained by the gas entering said gap in a-"direction away from the line of tangency of the condi'tit and casing.

ROLAND B. BOURNE.

REFERENCES CITED Theiiollowing references are of record in the fil'e of this patent:

UNITED STATES PATENTS Number-=- Name Date 753,845 Brockway etal Mar. 8, 1904 969,225 1 Walstromr Sept 6, 1.1910 984 ,2127 Gray Feb;: 14; 1911:

1,351,985 Andresenr. Semi-37,1920 1 ,'910;672:.- Bournev; -iMay-;23; "1933 Scarritt .Septl- #1940 2,328,161" Maxim .Aug.j:3l ,;1943:

I FOREIGN PATENTS Number Country Date;

432,372 Great Britain July-2531935 1 5