US2342426A - Apparatus for producing combustible gaseous mixtures at substantially constant pressures - Google Patents

Description

Feb. 22, 1944. 'r. H. RANSOME 2,342,426

APPARATUS FOR PRODUCING COMBUSTIBLE GASEOUS MIXTURES AT SUBSTANTIALLY CONSTANT PRESSURES Filed Oct. 1, 1941 3 Sheets-Sheet 1 1'NVENT0R. ZhLLENT 15f fimwso/w A rroe/wr Y5,

Feb. 22, 1944. T. H. RANSOME 2,342,425

APPARATUS FOR PRODUCING COMBUSTIBLE GASEOUS MIXTURES AT SUBSTANTIALLY CONSTANT PRESSURES Filed Oct. 1, 1941 3 Sheets-Sheet 2 N m I Q l l i I a Q I .m l

i I N I II 3 l I r? I if T I i I I I 5 1 Q I WQ v I N T I m INVENTOR. ZZumwrflfiANso/wa ATTORNEYS Feb. 22, 1944. 'r. H. RANSOME APPARATUS FOR PRODUCING COMBUSTIBLE GASEOUS MIXTURES AT SUBSTANTIALLY CONSTANT PRESSURES Filed Oct. 1, 1941 3 Sheets-Sheet I5 U INVENTOR. ZZLL ENT H Ban/soma- BY A T'TORNEY-s v proper combustion.

Patented Feb. 22, 1944 UNITED STATES PATENT OFFICE APPARATUS FOR PRODUCING COMBUSTI- BLE GASEOUS MIXTURES AT SUBSTAN- TIALLY CONSTANT PRESSURES 10 Claims.

This invention relates to apparatus for the manufacture oi a combustible gaseous mixture.

Where hydrocarbons of the methane series, such as butane, propane, etc., or a mixture of such gases are employed, the B. t. u. or calorific value is ordinarily too high for most uses and a dilutent, in the form of air or other gases, must accordingly be mixed with the gas to insure Apparatus for manufacturing such a dilute mixture of gases, for controlling the B. t. u. content and the pressure of said gases, forms the subject matter of the present invention.

The object of the invention is generally to improve and simplify the construction and operation of apparatus of the character described: to provide an apparatus which will control and maintain a substantially .constant predetermined calorific value of a gaseous mixture; to provide an apparatus which will maintain a gaseous mix ture at a substantially constant B. t. u. or predetermined calorific value and at a substantially constant pressure; and further, to provide an apparatus which is automatic in operation throughout and capable of large capacity production of diluted gases.

The apparatus is shown by way of illustration in the accompanying drawings, in which Fig. 1 is a diagrammatic view of the apparatus; I

Fig. 2 is an enlarged end view of the apparatus, showing parts in section;

Fig. 3 is a plan view of the apparatus, showing the aspirators arranged and controlled in pairs;

Fig. 4 shows a side elevation of Fig. 3; and

Fig. 5 shows an end view of Fig. 3.

Referring to the drawings in detail, and particularly the diagrammatic view shown in Fig. 1, A indicates a pipe line connected with a source. of gaseous fuel supply under pressure and B a service main into which a dilute mixture of the gaseous fuel is to be introduced. Connected with the service main is the discharge end of a Venturi tube 2 and mounted in said discharge end is a shut-oil. valve 3, which is normally open, and a check valve 4. Connected with the throat end 5 of th Venturi tube is a housing Ii and extending through the housing and aligning with the throat is a nozzle 1. The housing is provided with an air inlet 8 and a suitable form of air cleaner 9 may be applied to said inlet whenever required.

Fbrmed between the air inlet 8 and the nozzle 1 is a valve seat II and engaging said seat i a valve II which is provided with a downwardly extending stem II. This stem extends into a cylinder H and it is provided with a piston l5 which has a sliding fit in the cylinder.

Connecting with the lower end of the cylinder.

or at a point below the piston I5, is a pipe I6. This pipe is also connected with the nozzle 1 and is furthermore connected with the supply pipe A, as will hereinafter be described.

The gas under pressureis delivered tothe pipe l6 and the nozzle I when the apparatus is in operation. This pressure may be in the neighborhood of forty, fifty or more pounds and it is utilized not only to supply the nozzle 1. but also to lift or open the valve IL, To accomplish this, the end of the pipe 18 connecting with the cylinder H is U-shaped as shown and it is filled with oil or a similar liquid medium. Thus, when gas under pressure is supplied to the pipe l8, it will exert pressure on the oil and the oil will in turn exert pressure on the piston l5, thereby lifting the valve to an open position, opening movement of the valve being limited by the stop or pin l I. Gas, at the same time, will discharge through the nozzle 7 and as it enters the throat end of the venturi a suction action is produced which causes air to enter through the filter, the

air inlet 8, and to pass by the valve into the throat where a-mixture of the air and gas takes place. This mixture discharg s through the Venturi tube past the check valv 4 and the normally open valve 3 and. hence, into the service main D. No leakage of gas will take place around the piston II, as the pressure is not exerted directly on said piston but on the oil disposed between the gas and the piston. Any small amount of oil that'might leak by the piston will return by leakage when the apparatus is not functioning and as the oil is preferably of a viscous nature, chance, even of oil leakage, is very small.

An important feature of the present invention is the simultaneous operation of the nozzle 1 and the valve I l For instance, if there should be any material lag in the opening of the valve II when gas starts to discharge through the nozzle 1, a rich gaseous mixture would pass through the Venturi into the service main B and the B. t. u. content of the service main would, accordingly, increase, but by opening the valve simultaneously with the delivery of gas to the nozzle, a mixture of air and gas will instantly take plac and the B. t. u. content in the service main will be substantially constant.

A pull spring II is connected with the valve and this automatically closes the valve the moment the gas supply to the pipe I! is shut oif. Hence, the'valve automatically opens with introduction of gas to the nozzle and automatically and simultaneously closes when said gas supply is shut off.

Another feature of the present invention is to maintain a substantially constant pressure in the service main. To accomplish this, a take-off pipe is provided as indicated at 20. This pipe is connected at one end with the service main and at the opposite end with a bellows type of tube or diaphragm such as indicated at 2|. This, through a pin 22 actuates a lever 23 pivoted at 24 within a housing 25. An adjustable compression spring 26 is disposed above said lever and may be adjusted to permit the diaphragm 2| to expand and raisewith any predetermined pressure within the service main. For instance, if it is desired to maintain a pressure of 4 lbs. gauge in the service main, the spring 26 will be adjusted to permit the diaphragm to expand and maintain the lever 23 in a raised position when a 4 lb. pressure is reached. On the other hand, if the pressure drops below 4 lbs. the diaphragm will contract and the lever 23 will move downwardly. In so doing, it imparts a rocking movement to a mercoid tube such as indicated at 21. This is a standard type of tube containing a small quantity of mercury. When the tube assumes one tilted position, a circuit through a pair of contacts 28 carried by the tube is broken and when it assumes an opposite tilted position, the mercury runs to the other end of the tube and closes said circuit through the contacts. In this particular instance, the tube is moved by the lever 23 through means of a link 29 and when the pressure in the service main is below 4 lbs. the tube will assume a tilted position where the circuit through the contacts 28 is closed. Conversely, when the pressure reaches 4 lbs. the tube will be tilted in the opposite direction and the circuit will be broken.

The circuit referred to is utilized to open and close a valve 30 which shuts oil or supplies gas to the pipe'lG. This valve is actuated by a lever 3| connected through a link 32 to the movable core 33 of a solenoid magnet 34. This magnet is actuated by the circuit established through the contacts 28 of the mercoid tube. Hence, when said circuit is made, the solenoid will be energized and the valve 30 opened. 'This takes place when the pressure in the service main is below a predetermined pressure, for instance, 4 lbs. When the pressure is restored by operation of the Venturi tube and the cooperating nozzle 1, the flexible diaphragm 2| will move to tilt the mercoid tube and break the circuit and when the circuit is broken, the solenoid magnet will become de-energized and valve 30 will close. Hence, a substantially uniform measure is automatically maintained in the service main and by regulating the flow of gas through the nozzle 1, for instance, by means of valve 1', a mixture of a suitable B. t. u. content will be maintained. This mixture may be increased or decreased in B. t. u. content byregulation of the valve 1. Hence, the B. t. u. content of the final mixture is also under control.

In actual practice, the pressure on the main fuel supply pipe A may be 90 lbs. or more. This is usually steppeddown to a pressure of 40 or 50 lbs. before it reaches the valve 30 and this is accomplished by the use of a diaphragm actuated pressure regulator of standard form such as shown at 40.

In the diagrammatic view shown in Fig. 11 only nil one Venturi tube with cooperating nozzle and air inlet valve is shown. These cooperating mem bers form a unit commonly known as an aspirating unit. In actual practice, particularly where the load or demand on the service main is fairly high, there will be a considerable number of aspirating units connected with the service main as shown in Fig. 2 of the drawings. These units may be arranged in pairs, or larger groups, and each pair will in that instance be controlled by a single pressure actuated diaphragm such as shown in 2| and associated solenoid operated valves 30, that is--the diaphragm 2| will in that instance control two or more aspirating units simultaneously. On the other hand, each aspirating unit may have an individual control, but whether the aspirators are arranged in groups of two or more, or individually, each pair or individual unit will be regulated by a spring 26 to open or close one or more valves 30 at different pressures. For instance, the first pair indicated at C will go on the moment the pressure in the service main drops slightly below 4 lbs. gauge; if there is a further slight drop, the next pair indicated at D will go on, etc., until practically all units are in operation as would be the case when the demand or load on the service main has reached full capacity.

The drop in pressure in the service main between no load and full load may be as small as desired. For instance, it may be as little as oneeighth lb. gauge or less, as the diaphragms 2| many be adjusted by means of the springs 26 to function at exceedingly slight pressure variations: for instance, such pressure variations as are measured by inches of water. Thus, regardless of what the demand on the service may be, the aspirating units will automatically cut in and out as the demand increases or decreases and a substantially constant pressure will thus be constantly maintained.

Where butane or a like gas is employed as the source of fuel, it will usually be stored in a tank under a pressure of lbs. or so, said pressure being maintained either by heat or the application of compressed air. Under such a pressure the butane will be in liquid form. When drawn from the tank it will pass through heat exchangers, not here shown, and will thus be delivered to the pipe A at a sufliciently high temperature to maintain it in a gaseous form when entering the pressure reducing valve indicated at 40. At this point the pressure drop is considerable and as the gas is used valmost immediately thereafter, further heat application is usually unnecessary, but

if it should be necessary it could obviously be employed. The tank or source of fuel supply, heat exchangers, etc., are not shown, as standard equipment of this character may be employed.

While this and other features of my invention have been more or less specifically described and illustrated, I nevertheless wish it understood that changes may be resorted to within the scope of the appended claims, and that the materials and finish of the various parts employed may be varied according to what the experience of the manufacturer and varying conditions of use may demand.

Having thus described and illustrated my invention, what I claim and wish to secure by Letters Patent is:

1. In a gas mixing apparatus of the character described, an aspirator having an air inlet valve, means for shutting off or delivering gas above atmospheric pressure to the aspirator, a main' into which the aspirator discharges and means actuated by the withdrawal of a predetermined quantity of gas from the main for delivering gas under pressure to the aspirator and for simultaneously opening the air inlet valve.

2. In a gas mixing apparatus of the character described an aspirator housing having a suction producing nozzle, an air inlet valve on the housing, said valve being normally closed, a source of gas supply above atmospheric pressure connected with the nozzle a normally closed valve between the gas source and the nozzle, 8. gas service main into which the aspirator discharges and means controlled by a predetermined pressure drop in the service main for opening the valve supplying gas under pressure to the nozzle and for simultaneously opening the air inlet valve.

3. In a gas mixing apparatus of the character described an aspirator housing having a suction producing nozzle, an air inlet valve on the housing, said valve being normally closed, a source of gas supply a'bove atmospheric pressure connected with the nozzle a normally closed valve between the gas source and the nozzle, a gas service main into which the aspirator discharges. means controlled by pressure variations in the service main to shut oil or open the valve supplying gas to the nozzle and means actuated by gas under pressure supplied to the nozzle for causing simultaneous closing or opening the air inlet valve.

4. In a gas mixing apparatus of the character described an aspirator housing having a suction producing nozzle, an air inlet valve in the housing, said valve being normally closed, a source of gas supply above atmospheric pressure connected with the nozzle, a gas service main into which the aspirator discharges, means actuated by pressure changes in the service main for opening or closing an electric switch, and means actuated by the breaking or making of an electric circuit controlled by said switch for shutting off or supplying gas under pressure to the nozzle and for simultaneously shutting oil or opening the air inlet valve.

5. In a gas mixing apparatus of the character described a plurality of aspirator housings each having a suction producing nozzle, an air inlet valve on each housing, said valves being normally closed, a source of gas supply above atmospheric pressure connected with each nozzle, a gas service main into which the several aspirators discharge means controlled by a pressure drop below a predetermined pressure in the service main for supplying gas under pressure successively to the several nozzles and for simultaneously opening the air inlet valve associated with each nozzle said means shutting off the gas supply to the several nozzles in succession when the pressure increases in the service main, and simultaneously shutting off each air inlet valve when the gas supply to the associated nozzle is shut oil.

6. In a gas mixing apparatus of the character described, a Venturi tube, a housing connected with the throat end of the tube, a gas service main connected with the opposite end of the tube, a suction producing nozzle extending into the housing and aligning with the throat of the tube, a source of gas supply under pressure connected with the nozzle, a normally closed valve between the gas source and the nozzle, an air inlet valve for the housing, a piston connected with the valve, a cylinder for the piston, a liquid in the cylinder on one side of the piston, a spring normally maintaining the valve closed, and

means controlled by a pressure drop in the service main to openthe valve supplying gas to the nozzle, and for simultaneously applying gas pressure on the liquid in the cylinder to open the air inletvalve, said means automatically causing shutting off of both valves when a predetermined high pressure is developed in the service main.

7. In a gas mixing apparatus of the character described, a. plurality of aspirator housings each having a suction producing nozzle, an air inlet valve on each housing, said valves being normally closed, a source of gas supply under pressure connected with each nozzle, a normally closed gas supplying valve between each nozzle and the source of gas supply, a gas service main into which the several aspirators discharge, a pressure actuated device for each aspirator, said pressure actuating devices being connected with the gas service main, an electric switch cooperating with each pressure actuating device and adapted to be opened or closed thereby, means for adjusting the individual pressure actuated devices to operate in succession at difierent pressures in the gas service main, said pressure actuating devices when actuated closing an electric circuit through an associated electric switch,

means actuated by the closing of a circuit for opening an associated gas supplying valve to deliver gas under pressure to an associated nozzle, and means actuated by gas under pressure supplied to a nozzle for simultaneously opening an associated air inlet valve.

8. In a gas mixing apparatus of the character described an aspirator housing having a suction producing nozzle, a normally closed air inlet valve for the aspirator, a source of gas supply under pressure connected with the nozzle, a normally closed valve in said connection, a gas service main into which the aspirator discharges, electrically actuated means for opening the valve controlling the flow of gas to the nozzle, a pressure actuated device connected with the gas service main, means for adjusting the pressure actuated device to operate at a predetermined pressure in the gas service main, an electric switch opened or closed by the pressure actuated device, said switch making or breaking an electric current to operate the electrically actuated means for opening or closing of the valve controlling the flow of gas to the aspirator nozzle, and means actuated by the gas under pressure when admitted to the nozzle for simultaneously opening the air inlet valve.

9. In a gas mixing apparatus of the character described an aspirator housing having a suction producing nozzle, means connecting said nozzle with a source of gas supply under pressure, a normally closed air inlet valve for the aspirator housing, gas pressure actuated means connected with the source of supply for opening said air inlet valve, a gas service main into which the aspirator discharges, avalve normally closing the flow of gas from the source of supply to the aspirator nozzle and to the gas pressure actuating means for opening the air inlet valve, and means controlled by a predetermined pressure drop in the service main for opening said last named valve so as to simultaneously deliver gas under pressure to the nozzle and to open the air inlet valve.

10; In a gas mixing apparatus of the character described an aspirator housing having a suction producing nozzle, an air inlet valve for said housing said valve being normally closed, a source of gas supply under pressure connected with'the nozzle, a normally closed valve between the nozzle and the source of gas supply, a gas service main into which the aspirator discharges, a pressure actuated device for the aspirator. saidpressure actuated device being connected with the gas service main, an electric switch cooperating with said pressure actuated device and adapted to be opened or closed thereby, means for adjusting the pressure actuating device to operate 10 at a predetermined drop of pressure in the gas service main, said pressure actuated device when actuated closing an electric circuit through an associated electric switch, means actuated by the closing of the circuit for opening the gas supplying valve to deliver gas under pressure to the nozzle, and means actuated by the gas under pressure supplied to the nozzle for simultaneously opening the air inlet valve.

TALLENT H. RANSOME.

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