US2752934A - Liquid supply system - Google Patents

Description

July 3, 1956 H. w. BADBERG 2,752,934

' LIQUID SUPPLY SYSTEM Filed March 30, 1951 f I I iOh'gM a/Faam 14 I ifli eflhyflgenf 1 Wafer 5/0/qqe i I Tam? 42 i i i v w. 2. INVENTOR.

4% KJZ W This invention relates to pumpingsystemsfor firefighting apparatus, and more particularly to systems in which an air foam compound, wetting agent or the like is mixed with the water delivered therethrough.

It has become common practice in combating certain types of fires to utilize a chemical mixture which, when mixed with water, will produce a light foam. which will;

spread out over the area of the fire and effectively cut oif the oxygen. Notable among fires of this type are those occurring in large oil tank farms, or refineries, where the source of the combustion is oil, gas, or other inflammable.

hydrocarbon derivatives. Similarly, in fires which develop in fungible materials where untreated water has a tendency to run off without penetrating to the core of the fire, chemical mixtures called wetting agents have been developed which, when mixed with water, reduce the surface tension thereof and promote a more effective distribution throughout the burning material.

Accordingly, pumping systems on present day fire trucks are generally adapted to be equipped with some sort of apparatus for mixing these compounds. or agents with water and discharging them through a suitable hose line to the area of the fire. This apparatusvaries widely in construction, some types having a completely contained chemical pumping system in addition to the standard Water pumping equipment; others providing for injection of the chemical in the waterline on the discharge side of the pump; and yet others which are connected by a bypass line to the main water line. In all of these arrangements, operation of the equipment generally involves a complicated procedure of opening and closing valves,

charging tanks with chemicals, and other operations which in time of emergency are prone to result in costly errors. Further, in those systems which are provided with storage tanks for the chemical mixtures, congealing of the chemical compounds often occurs which results in contamination of the system and serves to render the equipment inoperative.

A primary object, therefore, of my invention is to provide an improved pumping system of this nature in which the mixing of the chemicals with the water is accomplished through a single manually operable valve.

Another object is to provide a system wherein the chemicals may be drawn directly into the water line as needed from the original containers in which they are stored; this, of course, eliminates any need for separate chemical storage tanks to beinstalled on the truck. In this connection, an important feature of my invention is in the provision of a single chemical intake line which may be readily transferred from one container to another, thus providing for continuous operation over a relatively lengthy period or a quick change from one chemical to another.

A further object is to provide apparatus which is capable of mixing chemicals in desired proportions into water streams varying from a minimum rate of flow to the maximum discharge capacity of the pump.

Still another object is to provide a system in which the chemicals are drawn into the waterline by the suction 'nited States Patent pressure of the pump rather than by gravity feed from.

the specification and are to be read in conjunction there with, like reference numerals are employed to indicate like partsof thevarious views.

Fig. 1 is a schematic drawing of a pumping system embodying my invention.

Fig. 2 is an enlarged longitudinal section through the mixing valve assembly. 1

For purposes of explanation, my invention will be (16? scribed in connection with its application to aconventional fire. truck equipped with a water storage tank and a. suitable pump for discharging water to the hose lines. Referringto Fig. 1, thenumeral 10 indicates the pump, 12 indicates. the water storage tank, vented to the atmosphereto allow gravity feed of the Water, and 14. indicates a container for a liquid air foam: compound, Wetting agent or other chemical which mightbe desired: to be mixed with water. The pump is provided on its discharge side with a manifold having a plurality of outlets 10a, and hose lines 16 are. connected to the outlets through fittings 18 pro vided with valves 20. The size of the hose lines is governed by the capacity of the pump, and in this connection it will be noted that I have. indicated both large and. small1 hose for dealing with. fires of varying. magnitude.

While in the conventional fire truck, the suction. side. of the pump is connected to the. water storage tank through. an open line, in the illustrated embodiment of, my invention the water supply line 22, which. is" provided with a conventional gate valve 23, leadsfrom the underside of the water tank 12 to. the inlet end of a mixing valve housing24, and the suction side of the pump is connected to opposite ends thereof by a suction line 26. i As.

will be explained presently, the chemical compound is drawn into the mixing valve housing through. another pipe line 28 connected to the top thereof which communicates;

with the chemicals in container 14 through. the lowerendof an intake pipe 30 inserted in the container and connected to the lineby a length of flexible hose 3,2. A selector or proportioner valve. 34 of the type having a plurality of settings for varying the throughput is provided in line 28 for selective control of the rate of flow of the chemicals, and a swinging check valve 36 is connected into the line immediately above the mixing valve housing 14 for preventing backfiow.

Turning now to a more detailed description of the mix ing valve and its housing, as may best be appreciated from Fig. 2, the housing, comprises a sleeve-like element adapted to threadedly receive at one end 22a the end of suction line 26 and provided with an enlarged cylindrical. bore 38. The opposite end of the housingis internally threaded as indicated at 49, and a generally cylindrical, tubular valve seat member 42 is screwed thereinto abut. an annular shoulder 24b formed in the interior of the housing. The outer end 42a of valve seat member is internally threaded to receive the end of the water supply line 22 and the inner end is formed as a short cylindrical section 42b which overlaps shoulder 24b to provide a valve seat 420. The chemical line 28 also communicates with the interior of housing 24, being threadly receivedin an outturned neck-like opening 24c located on top of inlet."

toward its seated position by a coiled compression spring] 48 encircling the valve stem and hearing at opposite ends against the inner face of the valve head and the legs of the spider. The resistance of spring 48 is such that the valve will remain seated against the static head of water present in the water supply line 22, and, as will be discussed more fully in describing the operation of the apparatus, will check the flow of water into the mixing valve housing until a vacuum is created by the pump in suction line 26.

In the operation of the device, the following initial conditions are set up. Valve 23 in the water supply line 22 is open and the selector valve 34 in the chemical line 28 is set at a closed position. The pump is then set in operation, and assuming that it is desired to discharge from a single hose line, the valve for that line is opened. Upon the opening of the valve to the hose line, a vacuum builds up in the suction line 26 which is transmitted to the mixing valve housing 24 and the valve 44 unseats to allow water to flow to the pump. The vacuum is also transmitted to chemical line 28, and by opening the selector valve 34, the chemical is drawn through the intake pipe 30 to the line and into the water stream flowing through the mixing valve housing. The mixture is carried to the pump, and forced out through the hose line being used where it is discharged through a suitable nozzle (not shown). At this juncture it is important to note that the selector valve 34 may be provided with a plurality of settings which are related to the discharge capacity of the hose lines being utilized. In other words, since water is drawn through the mixing valve housing in only a sufiicient quantity to supply the hose line being used, the selector valve position for a single line would be such as to limit the flow through the chemical line to that quantity which would give a desired proportion of chemical in the mixture. Obviously, as many positions are possible as there are variety of hose sizes and nozzles. Further, the quantity used to provide a desired mixture varies with difierent chemicals, e. g. a normal foam mixture contains around five percent of the air foam compound, while a wet water mixture generally only consists of 1% wetting agent. Therefore, since it is contemplated that the apparatus may be used interchangeably with difierent chemicals, the selector valve will also be provided with settings through which the percentage of chemical mixed into a given quantity of water may be varied.

If it is desired to operate two lines, the second line is merely cut in by opening its valve 20. Inasmuch as the discharge demand has increased, the suction also increases, and valve 44 opens further to allow the additional water required to be drawn into the pump. The 1 selector valve 34 is set at a new position to provide the correct quantity of the chemical, and the mixing takes place as previously described. It seems evident that the nature of the system admits of the discharge of chemically treated water through a hose line of any size consistent with the capacity of the pumping system, or alternatively, through a plurality of small lines. Thus complete flexibility is provided for dealing with fires ranging from relatively minor blazes to those occurring in oil tank farms and the like.

In dealing with fires of relatively long duration where it is possible that the supply of chemical in container 14 may be exhausted, continuous operation may be maintained through the simple expedient of transferring the intake pipe 30 to a full container as the original one is emptied. The flexibility of its connection to line 28 through hose 32 allows manipulation of the pipe as desired.

At the'close of the fire fighting operation, the entire system may be flushed out by inserting the intake pipe 30 in a container of water, and continuing the operation of the pump for a short time. Obviously, the water will be drawn through the chemical line 28, and any chemicals which otherwise might be left will be completely removed, insuring of clean equipment which may be immediately put in operation when the next emergency occurs.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the invention.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations.

As many possible embodiments may be made of the invention without departing from the scope thereof it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

1. Liquid mixing apparatus of the character described comprising a pump having an intake and a discharge, a liquid supply reservoir, a conduit from said reservoir to the intake of said pump, a spring-biased throttling valve in said conduit constructed and arranged to continually restrict the flow of liquid from said reservoir to said pump to the extent that the pressure in said conduit between said valve and the intake of the pump, when said pump is in operation, is always less than atmospheric pressure, said valve being automatically operable to open to diiferent degrees under the influence of varying pump suction pressures imposed in said conduit, a second liquid reservoir containing a supply of a second liquid, a liquid supply line from said second reservoir having one end immersed in the liquid therein and having an intermediate portion elevated above the level of the second liquid,

.the other end of said line being connected with said conduit intermediate said throttling valve and said pump, and valve means in the discharge of the pump operable to vary the throughput of the pump and thus impose difierent suction pressures in said conduit.

2. Liquid mixing apparatus of the character described comprising a pump, an open-top liquid reservoir elevated above the intake of the pump, a drain conduit from said reservoir to said pump intake, a spring-biased throttling valve in said conduit, said valve being normally closed and preventing flow of liquid from said reservoir to the pump intake by gravity alone and automatically operable to open to different degrees under the influence of varying pump suction pressures imposed on said conduit, a second liquid reservoir containing a supply of a second liquid, a liquid supply line from said second reservoir having one end immersed in the liquid in said second reservoir, an intermediate portion of said line being located above the level of liquid in said second reservoir and the other end of said line being connected to said conduit intermediate said throttling valve and pump, valve means in said last line adjustable to vary the throughput capacity of the line, and valve means in the discharge of the pump operable to vary the throughput of the pump.

References Cited in the file of this patent UNITED STATES PATENTS 1,174,307 Brown et al Mar. 7, 1916 1,324,572 Thomas Dec. 9, 1919 1,357,982 House Nov. 9, 1920 1,365,359 Vaile Jan. 11, 1921 1,617,095 Bacher 'Feb. 8, 1927 1,816,417 Witter July 28, 1931 2,164,153 Friedrich June 27, 1939 2,393,464 Granberg Jan. 22, 1946 2,543,941 Sargent Mar. 6, 1951 2,577,457 Freeman Dec. 4, 1951

Images