USRE16796E - Ments - Google Patents

Description

G. KEITH.

Nov. 22, 1927.

METHOD OF DELIVERING A MIXTURE OF GAS AND AIR 0R OXYGEN "FoRcoriiBUsTIom 19, 1916 2 Sheets-Sheet Original Filed Sept.

4 Nov. 22; 1927. Re. 16,79 6

M E-THOD"OFYDELIVERING A MIXTURE 0F GAS AND AIR.

2 SHEETSSHEET 2- METHUD 0F nnmvmuue A numuns or Ms AND AIR oa-oxmnn Eg n comausnou Original Filed Sept. 19. 1916 Sheets-Sheet 2 Reissued Nov. 22, 1927.

UNITED. STATES LAND, A BRITISH COMPANY.

I i This invention relates to an improved method of delivering a mixture of gas and 1 air (or oxygen) 'for combustion, for example, in a gas-fired furnace, oven or other in- 5 stallation, and it has for its primary object to render practicable the maintenance of the correct proportions of gas and air (or oxygen) irrespective of variations in the quantity of the mixture being dealt with. The improved method consists broadly in injecting one of the constituents of the mixture and inducing the flow of the other constituent, while governing the pressure'of the induced constituent to maintain the pres sure proportionate to the resistance offered to the flow,of the mixture, whereby variation in the resistance of the nozzle, of the furnace or the like being fired, or of the flue, may be automatically compensated for -it being understood that variation in the quality of the mixture mu'st otherwise result from variation in the resistance to be overcome.

In this connection it may be pointed out that variation of the resistance may be due to variable heating .u-p o f the mixture before it issues from the-nozzle, fluctuation of the temperature in the furnaceor the like and consequent variation in the contraction of the products of combustion, introduction or withdrawal of materials being heated, opening .or closing of doors or of dampers, variationsof pressure in the flue, or to other causes, ancLthat b the resent invention'the w effect on the: qua ity o the mixture of all such possible causes of variation may be automatically compensated for.

The preferred form of governing device employed comprises a dia hragm casing in i which is fitted a thin mem rane operatively connected with a valve serving to regulate the admission to the casing of the induced medium, the com artment of the casing at the back of the diaphragm being in com- 5 munication with a point in the path of flow of mixture-preferably on the delivery side of the injectorso thatit is influenced by variations in the static pressure obtaining in that part of the injector. In certain cases, where the induced medium is gas, it may be 'suificient for the purpose in view so to govern the gas pressure that the gas is previously brcug t to a pres.

PATENT OFFICE."

GEORGE KEITH, OF LONDON, ENGLAND, A SSIGNOR, BY DIRECT AND MESNE ASSIGN- MENTS, TO JAMES KEITH & BLACKMAN COMPANY, LIMITED,

OI LONDON, ENG- METHOD OF DELIVERING A MIXTURE 01? GAS AND AIR OR OXYGEN FOR COMIBIISTION.

Original 1T0. 1,801,272, dated April 22, 1919, Serial No. 121,030, filed September 19, 1918. Patented. in Great Britain, 1915, No. 16,711. Application for reissue filed November 1, 1926. Serial No. 145,675.

sure equal to that prevailing at the final outlet for the products of combustion, e. g. to atmospheric pressure, if the final dischargebe directly into the atmosphere, or to the pressure prevailing in the chimney.

In case the gas pressure is to be maintained at atmospheric pressure, the back of the diaphragm maybe left open; if the as is to be brought to a pressure equal to tfiat prevailing in the chimney, the connection from the back of the diaphragm may be led to the chimney.

The invention is illustrated by way of example in the accompanyingdrawings in which Fig. 1 is a vertical section showing 'the dia hragm casing and injector with 'a connection from the back of the diaphragm to a point on the delivery side of the injector. Figs. 2, 3 and lrepresent diagrammatically three forms of connection. Fig.

5 is a vertical section through the diaphragm casing.

In the construction shown, the governor is designed to governthe pressure of gas-gas being the induced medium, and the injected medium being air or oxygen. It will be understood, however, that with suitable modification the governing device may be adapted to govern the pressure of the air or oxygen where the induced medium is air or suitable form of valve, balanced or otherwise,

maybe provided. 5 H

. The valve 3 is somounted as tobe immovable laterally though not liable to be jammed with grit or the like, beingcarried by a hinge pin assing throu h lugs on a bracket 1 member 6 tted within t e casing 4.

The membrane 2 is operatively connected with the valve 3 b a closely wound helical spring 7 one end 0 which is connected to. the

membrane 2 and the other end of which is connected to the valve-operating lever 8, the spring being of suflicient strength to insure that the valve 3 shall be properly closed when the spring 7 is stressed but being capable of. further extension in case of such accumulation of pressure of the gas on the membrane when the outlet of the governor. is closed as to move the membrane against the face of the'diaphragm casing-the arran ement being such as to obviate straining of die valve.

The connection between the back of the diaphragm and the injector is represented by a tube 9 which is led to the expansion tube 10 of the Venturi tube and which may terminate flush with the internal wall of the Venturi tube with its mouth facing across stream, as in Figs. 1 and 4, or may project into the interior thereof with its mouth faci g up stream, as in Fig. 2, or down stream, as in Fig. 3, or in any intermediate position, according as it is intended to establish pressure above or below that of the mixture in the expansion tube having regard to the conditions of construction and operation.

Whichever of the arrangements described be ado ted, increase or decrease of the resistance o ered to the flow is instantaneously res onded to by the governor, the consequent1al alteration of the pressure of the gas sup ply to the injector resulting in maintenance of the uniformity of quality of the mixture.

It is to be understood that the connection to the back of the governor diaphragm need not be taken from the expansion tube but may be conveniently taken from any point between the inlet of the injector and the burner nozzle, or even from the furnare itself, although in the last mentioned case there will be no provision for compensation .larly applicable for delivering a self-burningmixture of gas and air to gas-fired furnaces, it is to be understood that the invention is not confined to such application, but includes the delivery of gas and air (or oxygen) in given proportions to ovens, burners or other installationslwhether the mixture to be consumed be self-burning or otherwise.

If air (or oxygen) be the induced medium, the governing device will, of course, be interposed in the air (or oxygen) inlet connection and will serve to govern the pressure of the air (or oxygen) admitted, while the gas connection will be taken to the nipple of the injector.

What I claim is:

The hereindescribed method of delivering a mixture of gas and a comburent medium for combustion, consisting in injecting the entire volume of one of the constituents of the mixture and thereby inducing the flow of the induced constituent and governing the pressure at which the induced constituent is supplied in direct proportion to the virtual pressure obtained at any predetermined point in the path of the mixture.

In testimony whereof I have signed my name to this specification.

GEORGE KEITH.

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