US2782739A

US2782739A - Distribution of fluids

Info

Publication number: US2782739A
Authority: US
Inventors: John G Freer
Original assignee: Union Oil Company of California
Current assignee: Union Oil Company of California
Priority date: 1955-04-22
Filing date: 1955-04-22
Publication date: 1957-02-26
Anticipated expiration: 1974-02-26

Description

Feb. 26, 1957 FREER 2,782,739

DISTRIBUTION OF FLUIDS Filed April 22, 1955 4p 4 6 l r r 1 l l Ava; flame! 444mm. I4 (75% -Haz,

AG NT- lava/1% DISTRIBUTION OF FLUIDS John G. Freer, Anaheim, Calif., assignor to Union Oil Company of California, Los Angeles, Calif., a corporation of California Application April 22, 1955, Serial No. 503,286

14 Claims. (Cl. 111-7) This invention relates to a method and apparatus for the dispensing of fluids and in particular relates to the dispensing of a plurality of streams of fluid from a single source wherein each of the plurality of flows has a predetermined flow rate. Specifically this invention relates to an improved method and apparatus for the division of a single fluid stream into a plurality of individual streams each having a flow rate bearing a predetermined relation to the flow rates of the other streams. The present invention is particularly related to an improved method and apparatus for distributing liquids in a plurality of individual streams on sloping ground, either through subsurface or surface application, and in which the disturbing influences of the liquid head difierences can be completely eliminated, or, in a practical sense, eliminated to any desired degree depending upon the choice of specific gravity for the compensating fluid and the exactness of the physical arrangement.

The controlled rate dispensing of fluids, either gaseous or liquid, in a plurality of closely controlled streams of interrelated flow rate from a single flow source, is involved in many industrial and agricultural operations. A few of these include the injection of reagent fluids in separate streams and at several difierent locations in a chemical reaction process, the filling of a plurality of containers simultaneously with predetermined volumes of liquid such as in the canning of lubricating oils, vegetable juices, and in the bottling of liquid commodities such as beverages, the injection of gaseous or liquid fertilizers such as ammonia or ammonium hydroxide simultaneously at a plurality of either aboveground or underground delivery points, and the like. Other liquid synthetic fertilizers which may be so dispensed include aqueous solutions of the soluble salts of ammonia, potassium, phosphorus, sulfur, and the like and these may be applied in a plurality of streams simultaneously to several individual streams of irrigation water aboveground, or in an underground application as in combination with some sort of conventional soil tilling operation or as a separate operation.

l-leretofore each fluid stream in the plurality was individually adjusted by providing a main conduit opening froma storage container and delivering fluid into a manifold or header from which a plurality of branched outlet conduits opened. In each of such bnanch conduitswas usually located some sort of flow controller such as. a valve or an orifice. This arrangement has a number of disadvantages. The principal problem when the flow control device is of the fixed area type, as are the common sharp edge and short tube type orifices and individual manually operated control valves, is that with attempted increases in fluid delivery rate by raising the source pressure, this source pressure increases at a much greater rate than does the flow it initiates. In dispensing of liquids, positive displacement pumps of the piston, diaphragm, bellows, or gear type are conventionally used in order to meter the total liquid output accurately at the pump. An attempt to increase the total delivery rate through fixed size restriction openings by increasing pump nited States Patent speed or stroke, rapidly causes an excessive build-up in pressure at the pump discharge. These pressure build-ups are readily capable of and frequently result in rupture damage to the pump or the equipment through which the liquid is distributed.

There is an additional problem in the application of liquid fertilizers or other liquids to the soil involving flow rate variation in the individual streams caused by diflerences in liquid head when the manifold conduit from which the liquid is distributed is not level. This difliculty may arise either when distribution of the liquid in a plurality of streams is attempted into a plurality of irrigation water flows at different levels along the slant height of a hill or from moving equipment which is drawn more or less along the contours of the hillside. In either case there may be an appreciable diflerence in elevation between the upper and lower ends of the main distributing conduit so that the actual pressure initiating the flow of the individual liquid streams, and hence their flow rates, will vary widely. The present invention as hereinafter more fully detailed successfully eliminates this problem by employing a plurality of specially designed liquid dividers and flow controllers which are provided with a compensation means whereby the flow rate of each of the plurality of liquidstreams is completely independent of the aforementioned variations in liquid head. Furthermore the liquid divider and flow controller is modified so as to produce a plurality of individual liquid streams, the volumetric flow rate of each of which varies in a linear fashion with the pressure of the liquid applied at the divider inlet, and which exhibits a very eflective damping action on pulsating flows from the pump.

The present invention is therefore directed to an improved method and apparatus for the division of a fluid into a plurality of streams and the distribution of said streams at predetermined variable rates in which the aforementioned dilficulties are avoided.

It is an object of the present invention to provide a fluid splitting and distributing device adapted to the division and delivery of a plurality of fluid streams at equal or otherwise predetermined individual flow rates. I It is a more specific object of this invention to provide a device for the automatic regulation of the back pressure of the inlet fluid flow in a fluid dispensing device delivering a plurality of fluid streams while permitting predetermined division of the flow through a plurality of variable orifices.

It is a further object of this invention to provide an improved liquid dividing and distribution system in which the flow rate of individual liquid streams is linearly variable with applied liquid pressure to within about plus or minus 1-3% and in which the individual flow rates are, to any desired degree, independent of liquid head eifects at the divider inlet permitting uniform side hill application.

It is a more particular object of this invention to provide an improved device for the dispensing of liquids in a plurality of streams, such as in the dispensing of liquid fertilizers into irrigation water or into the ground, in which the individual liquid flow rates have a linear relation to the inlet liquid pressure and do not vary with elevation of this device relative to the supply point at which the liquid to be distributed is introduced into the manifold from which the individual liquid streams are taken to the device.

Other objects and advantages of the present invention will become apparent to those skilled in the art as the description and illustration thereof proceeds.

Briefly .the present invention comprises in combination a fluid dispensing system comprising a container suitable for storage of the fluid to be dispensed, a fluid pressure control means such as a valve or a variable delivery 3 pump connected in fluid receiving relation to the container, and an especially designed spring loaded variable orifice device having a single fluid inlet and a plurality of fluid outlets, the outlets each containing an orifice of predetermined size whose cross-sectional area open to fluid flow is opened or closed to a degree depending upon the pressure of the inlet fluid. A movable valve member is r-eciprocably disposed adjacent the inlet ends of a plurality of orifices and is spring loaded by means of at least one adjustable loading spring whereby the valve member is biased toward a position at which all of the orifices are normally closed.

The storage container referred to above and the pump and the variable orifice device or devices may be mounted upon any suitable kind of moving farm machinery adapted to be drawn or driven across the land to which the liquid is applied. The pump may be provided with its own prime mover but preferably is directly driven from a ground contacting wheel so as to discharge any predetermined quantity of liquid as a function of the ground area covered. In the specific case illustrated, a transverse tool bar is supported from the trailer and in turn supports a plurality from 4 to 36 or more injection shanks each extending to points from 6 to 12 inches below the ground surface. A transverse liquid supply manifold is also provided parallel to the tool bar. Each injection shank is provided with a conduit for fluid flow which opens into the shank from a liquid dividing and flow controlling device hereinafter more fully described, and which devices in turn receive fluid from the supply manifold. These devices are further provided with means for compensating for liquid head eflects on the individual liquid flow rates when the equipment is drawn along a hillside contour while the tool bar and supply manifold extend along the slant height of the hill.

It should be understood however that the invention is not restricted to moving farm equipment, because it may be employed to discharge individual liquid streams into a plurality of irrigation water flows moving in a plurality of more or less parallel courses disposed side by side at different elevations along a hillside. In either case the compensation for liquid head effects has proven eminently successful in maintaining the individual liquid flow rates at equal values or at values having any predetermined relation to one another independent of differential liquid hydrostatic head effects.

An essential element of the apparatus of this inventron, as indicated above, consists in a liquid flow divider and controller. In the apparatus of this invention several of these flow dividers may be employed depending upon the number of individual liquid streams desired. As briefly indicated above, this divider consists of a pressure resistant valve body having an inlet channel, a movable valve member disposed within the channel, a plurality of orifices opening laterally from this channel and adapted to be closed by the movable. valve member, and a diaphragm attached to the valve member within the valve body.

The inlet pressure of the fluid to be divided and dispensed acts on a diaphragm integrally attached to the valve member and acts against the loading spring which in one modification causes the valve member to move after a preset minimum pressure is reached so as to expose at least a portion of each of the orifices and permit a small amount of fluid to flow through the orifices in a predetermined ratio. At a constant inlet fluid flow rate, the reciprocable valve member reaches and maintains an equilibrium position such that the quantity of fluid flowing through the orifices dissipates most of the inlet pressure by producing a pressure drop equal to the pressure difference between the pressure necessary to open the orifices against the loading spring and the outlet pressure head of the fluid into which the flow is being delivered by the distributing device. The loading spring,

being adjustable, permits a predetermined minimum flow pressure to be set which the pressure source must exceed before the variable orifices are opened at all. For purposes of the present discussion this will be defined as Po, and the pressure source will be a pump. When the outlet pressure of the pump, which usually is substantially the same as the fluid inlet pressure at the distributing device and herein defined as Pr, exceeds the preset minimum value Po by an amount equal to AP, this excess inlet pressure AP opens the orifices by an amount sufiicient to permit a fluid flow through each orifice, the quantity of which is governed by the difference between the inlet pressure Pr and the outlet pressure head. With further increases in pressure effected to increase the fluid delivery rates, the higher values of AP cause the valve member to move to open greater areas of the orifices resulting in increased fluid flows through each orifice sufficient to dissipate the higher value of Pl. At maximum rate, the orifices are opened entirely to permit a fluid flow which is substantially equal to the capacity of the pump thus preventing the build-up of destructive pressures under any conditions of fluid flow desired. In this manner the maximum pressure and energy necessary to discharge a certain volume of liquid are considerably reduced relative to the fixed area flow restrictions. It is to be noted that a spring with a low spring constant (pounds per inch deflection) will permit the maximum flow rate with less increase in Pi than will occur using a spring with a high spring constant;

A slightly modified and highly desirable form of liquid divider comprises one in which a primary and a secondary loading spring operate against the movable valve element, the primary spring being adjusted so that it applies no compressive force against the valve member in the closed position. The result obtained by this modification is the immediate opening of the valve with applied pressure against a relatively light force of the secondary spring whereby a nearly perfect direct proportionality of individual flow rate with applied pressure is attained as illustrated in Figure 5 With the valve element seated, only the secondary loading spring exerts a relatively light load. on the valve element. The primary loading spring being normally shorter is not placed in compression until the applied fluid pressure raises the valve element against the compression force of the secondary spring. The pri mary spring is selected to have a relatively high spring constant, that is one of the order of 10 to times that of the secondary spring. The device is adjusted so that when the secondary spring seats the valve element, the primary loading spring is under no compression force whatsoever and being shorter or otherwise adjusted to have a small clearance from its stop at one end. The main purpose of the secondary spring is to seat the valve member when the delivered flow has stopped, which eliminates syphoning of the system. The secondary effect is that with low applied pressures the valve element opens by compressing the secondary loading spring first, thereby giving a linear characteristic at low applied pressures and flow rates. With further increases in pressure, the restraining force is substantially entirely supplied by the primary loading spring which maintains complete linearity over the higher applied inlet pressures. Extensive testing of this device has shown it capable of producing individual liquid flow rates which are linear over their entire range to an accuracy of within 1 to 3%. The diaphragm, valve element, and compression spring( s) form a damped springmass system with an approximate natural frequency of C. P. S. for the specific models tested. This situation implie that pulsating flows into the distributor at or near 150 C. P. S. will get the least damping action. The frequencies were limited to the range 300 to 4400 C. P. S., and over that'range pulsation was nearly completely eliminated in the outlet flow. It also appears that more effective damping is obtained at high flow rates due to seeondary damping occurring at the variableorifice restriction. Although either of the liquid dividers and flow controllers briefly discussed above may be applied in the apparatus of this invention and either may be compensated to eliminate liquid head effects as hereinafter described, the latter modification is preferred in cases where improved linearity of liquid rate variation with applied pressure is desired at low flow rates, or positive seating action of the valve element is desired.

The structural detail of the apparatus of this invention and the method in which it is used to obtain the results outlined above will be more readily understood with reference to the accompanying drawings in which:

Figure l is a semi-schematic side elevation of a moving vehicle adapted to carry the liquid distribution system of this invention,

Figure 2 is an elevation view taken at right angles to that in Figure 1 and showing the transverse tool bar, injection shanks, liquid divider and regulator elements, and the means for compensating for elevation differences,

Figure 3 is a schematic view of the apparatus in Figure 2 when operated in an inclined position as on a hillside and indicating the various liquid heads which ordinarily cause undesirable variations in the individual liquid flow rates,

Figure 4 is a detailed elevation view in cross section of the liquid divider and flow controller device, and

Figure 5 is a graph showing the linear flow rate variation with pressure and the effect of the employment of a primary and a secondary loading spring.

Referring now more particularly to Figure l, a trailer provided with wheels 12 is drawn through. tow bar 14 by means of any suitable piece of moving equipment not shown. A farm tractor or the like is obviously suitable for this purpose. A storage tank 16 provided with filling hatch 18 is disposed on trailer 10. Dispensing pump 20 is connected through inlet line 22 to tank 16. Although pump 20 may be provided with its own prime mover, such as a small gasoline enginenot shown, it is preferable to connect it through a variable drive means, also not shown, to trailer wheels 12 or a separate wheel riding on the ground by a chain drive 24 or the like. Suitable pulleys of different diameters or other equivalent means are available to vary the ratio of pump impeller revolutions to trailer wheel revolutions, or a pump with integral variable output control may be used. In this way the volume of liquid dispensed in a given distance traveled or per acre covered may be maintained at any predetermined value.

The pump output is connected through line 26 to a lateral distribution or supply manifold 28 (the end of which only is shown in Figure l) to which is connected a plurality of liquid flow dividers and controllers 30. The rear end of the trailer is provided with a transverse tool bar 32 which is connected to the trailer by means of clamps, a plurality of vertical support bars 36, and linkages 33 and 40 to the rear of the trailer. Any suitable mechanical means for raising and lowering this assembly relative to the trailer, such as pneumatic cylinder 42, may be employed. Such means are conventional and well known to those skilled in the art. Transverse distributor manifold 28 is also supported from the same movable assembly that supports tool bar 32, and is connected to liquid outlet line 26 through a flexible conduit;

A plurality of injection shanks 44 is clamped by means of clamps 34 to tool bar 32. These are preferably bars of spring steel, either round or square in cross section, having a thickness of the order of 0.75 to about 1.25 inches, and formed into the shape shown in Figure 1. This shape includes one or more helical turns indicated generally at 46. The end of the injection shank is provided with ashoe 48 disposed when in use below'ground level 50[ The rearward portion of shoe 48 is provided 6 withan opening 52 into which liquid is introduced for direct discharge into the ground. Each shoe is connected by means of a pipe 54 and a flexible conduit 56 to one outlet port of one of the liquid dividers 30.

As the equipment above described is drawn along the surface of the earth, liquid is pumped from tank 16 through

lines

22 and 26 at a rate determined by the velocity of the trailer along the ground surface. This liquid is passed through manifold 28 into a plurality of liquid dividers 30 wherein a plurality of individual liquid streams are produced. Each of such liquid streams is then passed through conduits 56 and 5d into an individual injection shank for underground application. It may be readily understood that if the view in Figure l were taken down hill, that the pressure applied to the lowermost flow divider 30 would be greater than that applied to the uppermost divider by an amount equal to the differential liquid head in the supply manifold between the two. Since the degree to which the orifice openings are exposed to produce the individual liquid flows is governed by the liquid pressure at the distributor inlet, it may be seen that the individual flows from the lower distributor will also be greater than those from the higher distributor unless the compensation means of this inven tion is employed.

Referring now more particularly to Figure 2, an elevation view taken at right angles to the apparatus in Figure l is shown. Herein transverse tool bar 32, injection shanks 44 and shoes 48 connected thereto are shown. The transverse supply manifold 23 is also shown extending equidistant from supply point 66 to the inlets of a pair of

liquid flow dividers

62 and 64 which correspond to element 30 indicated generally in Figure 1. In the apparatus shown, a plurality of sixteen injection shanks and shoes are employed and each liquid divider feeds eight individual shanks. The lines connecting each shank are indicated generally as 56 as indicated in Figure l and open downwardly along the rearward portion of the injection shanks through conduits 54. Supply point 60 denotes the point at which pump outlet conduit 26 opens into the midpoint of manifold conduit 28 indicated in Figure 1. At this point the flow divides into two streams, each one going to each liquid divider, and from each of which eight individual streams are supplied to the injection shanks as shown.

Across the midsection of

dividers

62 and 64 is a diaphragm integrally connected to the movable valve element referred to above and which is detailed in Figure 4 described below. The fluid to be divided is supplied below the diaphragm and the individual liquid streams are also supplied from the divider below the diaphragm. The space above the diaphragm in each flow divider is connected respectively through equalizer conduits 66 and 68 to the bottom of a compensating reservoir 71 which is normally open to the atmosphere through port 72. Reservoir 70, lines 66 and 68, the upper portions of

dividers

62 and 64, and the lower portion of reservoir '70 contain a compensating liquid having a specific gravity substantially equal to that of the liquid being dispensed. The compensating system is filled with this liquid to an extent that liquid level 74 in reservoir 7% lies at the same elevation as the diaphragms in

dividers

62 and 64 when the entire apparatus is on level ground. It is also neces sary that all air or vapor be eliminated from this system, and the arrangement should be such that any vapors formed are free to vent themselves through the conduits into the reservoir 7i). When the device in Figure 2 is drawn along a hillside so that tool bar 32 and manifold 28 are inclined, the compensating liquid differential head counterbalances the liquid differential head in manifold 28 so that the net pressure differential across the dia phragm in each of the liquid dividers is equal at all times regardless of the attitude of the equipment. This counterbalancing effect is more clearly illustrated in Figure 3 in which the apparatus of Figure 2 is' schematically shown in an inclined position.

Referring now to Figure 3, the operation of the compensating system is shown. Herein supply point 60, compensating reservoir 70,

liquid dividers

62 and 64, transverse manifold conduit 28, and compensating conduits 66 and 68 are shown as in Figure 2.. The eight branch conduits opening from dividers 62 and 64- have been eliminated from Figure 3 for sake of clarity.

In the system shown Pm and P172 are the gauge pressures at the bottoms of the diaphragms in

dividers

62 and 64 respectively. Pm and Pt2 are the gauge pressures above the diaphragms in

dividers

62 and 64 respectively. P5 is the supply pressure at supply point 60. P: is the frictional pressure drop in each half of manifold conduit 28 between supply point 60 and the fluid inlet at the bottom of

dividers

62 and 64 resulting from the fluid flow therethrough. Pa is the datum pressure of the compensating system in the upper portion of reservoir 70. This is ordinarily atmospheric pressure but may be any other pressure as desired. APi and AP3 are the equivalent pressures due to static liquid heads I11 and 113 in manifold conduit 28 between supply point 60 and the diaphragms in

dividers

62 and 64 respectively. APz and Al are the pressures equivalent to the static liquid heads In and 11 in the compensating system in lines 66 and 68 respectively.

With the system level as indicated in Figure 2 the following relationships have been found to exist between the pressures and pressure differentials listed:

The pressures below and above the diaphragms are:

The net diaphragm pressure is:

and since by symmetry of physical arrangement [11:11 and 112 114 for the level system, or

at all how rates.

Since the outlet flow from the distributor is directly proportional to net diaphragm pressure, Q=K(Pb-Pt), then the flows are equal.

When the system is inclined as indicated in Figure 3 the following relationships exist:

The pressures below and above the diaphragms are:

Then

AP1AP2= AP3+AP4 and AP1Pa AP2= -AP3 -Pa+AP4 which is the same result as for the system in a level position.

Therefore, the gravity head differences are completely compensated in the apparatus described and changes in inclination have no effect upon the liquid fiow rate of the individual streams. This has been borne out by comprehensive testing of the equipment under actual operating conditions.

It is therefore apparent that the liquid flow rates discharged in individual streams from each liquid divider are equal to the flow rates of individual streams discharged from all other liquid dividers at other elevations. Accordingly the present device installed on moving farm equipment can be drawn across level land or along hillsides in either direction and at all times the equipment will discharge a plurality of streams at rates which do not vary with the change in attitude of the equipment.

Referring now more particularly to Figure 4 the structural detail of the how divider and regulator is shown. This device consists essentially of a pressure resistant body portion 76 and a cap or upper portion 78 which is secured by means of cap screws 80. The body portion is provided with a lower fluid inlet channel 82 threaded at its end to receive standard pipe fittings. A plurality of between about four and twelve orifices 84 open radially from the inlet channel and are also provided with threaded portions for pipe attachment. The actual number of outlets is limited by the physical sizes of the inlet chamber and the orifices. In the pilot models, 8 outlets were used. Movably disposed within the fluid inlet channel is valve element 86 shown in the seated position at which orifices 84 are closed. The upper portion of valve element 86 is provided with a spindle 88 which is threaded to receive nut 90 whereby washer 92 is clamped against diaphragm 94 and lower washer 96 at the top of the valve element.

Diaphragm 94 sealed between body and

cap elements

76 and 78 effectively divides chamber 98 contained within the cap and body element combination into a lower portion 100 and an upper portion 102. The lower space 100 communicates through apertures 104 with the lower portion of fluid inlet channel 82 at a point below valve element 86. In this way the inlet pressure is exerted not only against the lower surfaces of the valve element but also against the lower surface of diaphragm 94 tending to raise the valve element and open the orifices. Slots 106 are milled in the lower periphery of valve element 86 opposite each orifice 84 and may be of any desired shape so as to obtain the required change in open area with valve element travel.

Disposed within upper chamber 102 are primary loading spring 106 and secondary loading spring 108 in coaxial relationship to one another. The loading springs rest on the upper surfaces of the movable valve element and tend to resist valve element movements induced by the application of fluid pressure in inlet channel 82. As described previously a clearance 110 is provided between the upper end 112 of the spring and the loading spring adjustment cap 114. Secondary spring 108, however, has no such clearance and is maintained under light compression at all times. In one example of this invention designed to distribute aqueous ammonia at pressures between 0.1 and about 50.0 p. s. i. g., the secondary spring constant was 10 pounds per inch, while the primary spring constant was 1,000 pounds per inch. A clearance of 0.080 inch when the valve was closed was provided by adjustment of cap 114. As shown the flow rate of each individual stream was linear with changes in pressure over its entire range. The individual liquid streams were discharged at rates which were all within 13% of the mean value.

The upper space 102 comprises the space into which the compensating fluid previously described is introduced soas "to nullifyeffects of'hydrostatic head in the equipment of this invention. Loading spring cap 114 is provided with a lock nut 116 to maintain clearance 110 at the desired value to secure linearity at the lower ranges of inlet pressure. Cap 114 is also provided with a compensating fluid channel 118, fitting 120, and compensating conduit 122. The latter conduit 122 corresponds to conduits 66 and 68 indicated in Figures 2 and 3. With this construction, the net force acting on movable valve element 86 tending to displace it from its seated position shown and to open the orifices 84 is the difference between the fluid pressure Pb in inlet channel 82 and the pressure Pt of the compensating fluid in upper space 102. As the entire apparatus shown in Figures 2 and 3 is moved into an inclined position, the increase in inlet fluid pressure due to hydrostatic head is exactly counterbalanced by an increase in hydrostatic head in compensating fluid whereby the net pressure difference remains the same so that the degree of orifice opening likewise remains the same. This has been discussed above.

In Figure 5 is shown the linear relationship between the flow rate Q of an individual liquid stream from a flow divider such as that shown in Figure 4. The solid line 124 indicates at its lower curved portion that at very low pressures the valve closes at some finite minimum pressure greater than Zero. The dotted portion 126 indicates the extended linearity secured by employing the primary and secondary loading spring system as described above including the clearance 110 at one end of the primary loading spring. The clearance 110 shown in Figure 4 is determined by testing the device and adjusting the clearance so that the movable valve element does not close until the inlet pressure drops to zero. At this point lock nut 116 is tightened and the flow characteristic of the device is completely linear as indicated in Figure 5.

The device of this invention was tested through the ap plication of aqueous ammonia of 24% concentration on hilly farm land by means of an applicator having the same general structure as is shown in Figures 1 and 2. This device had sixteen injection shanks spaced on sixteeninch centers. The equipment was moved at a forward velocity of about 3 miles per hour, the feed pump was adjusted to supply aqueous ammonia through the injection shanks at a rate of 70 pounds of nitrogen per acre, and the flow rates in individual shanks were checked as the equipment was drawn along both level and hilly land. With the compensator system consisting of reservoir 70 and compensating lines 66 and 68 connected to the tops of two flow dividers which are detailed in Figure 4 the individual flow rates were found to within :1% of the mean value regardless of the change in slope of the tool bar and distribution manifolds. With the compensation system disconnected and the tops of the compensators left open to the atmosphere the flow rates of the lower eight shanks were found to be as much as 6% higher than the flow rates of the upper eight shanks when the apparatus was drawn along the contour of a hillside. It is notable that at lower flow rates the deviation becomes of increasing magnitude. In the present test the compensating liquid employed was raw water, but by employing other liquids or mixtures selected on the basis of low volatility and specific gravity substantially equal to that of the aqua ammonia, the compensation can be made perfect. 7

Although the present invention has been described as being adapted to use on moving farm machinery, it should be understood that the same advantages may be obtained as far as equality of flow is concerned in the individual injection of liquids such as fertilizer solutions into a plurality of irrigation water streams flowing along contour lines at different levels on a hillside. It should also be understood that the compensation'system should be applied generally to neutralize the effects of hydrostatic head and elevation in any flow division and control sys- 10 tem of the type described. Obviously the present in-' vention is not intended to be restricted to the particular liquids herein discussed for the principles are general and may be applied generally to liquid distribution problems.

A particular embodiment of the present invention has been hereinabove described in considerable detail by way of illustration. It should be understood that various other modifications and adaptations thereof may be made by those skilled in this particular art without departing from the spirit and scope of this invention as set forth in the appended claims.

I claim:

1. An apparatus for dispensing a plurality of fluid streams bearing a predetermined volumetric relation to each other which comprises a fluid storage vessel, a fluid inlet to said vessel, a manifold conduit, means for supplying fluid from said vessel to an intermediate point along said manifold conduit, a plurality of fluid divider and flow regulators, each of said regulators comprising a pressure resistant body element provided with a fluid inlet channel extending therethrough and a plurality of orifices opening from said channel through said body element, means connecting each inlet channel to said manifold conduit, a valve element movably disposed in each inlet channel, a loading spring system biasing said valve element into a position closing said orifices whereby the pressure of fluid supplied said inlet channel from said manifold conduit tends to move said valve element and open said orifices and permit flow therethrough, a plurality of conduits connecting the outlet ends of said orifices to fluid delivery points, a compensating fluid reservoir, and a compensating fluid conduit connecting said reservoir with each of said fluid regulators at points on the opposite side of said valve elements from said fluid inlet whereby the net fluid pressure tending to move said elements is independent of differential fluid heads in said manifold conduit.

2. An apparatus according to claim 1 in combination with a wheeled vehicle supporting said storage vessel, said manifold conduit, and said fluid dividers, in combination with a pump comprising said means for delivering said fluid to said manifold conduit, and a variable speed drive connecting said pump to a wheel riding in contact with the ground adapted to deliver a volumetric rate of fluid from said pump that is proportional to the speed of said vehicle.

3. An apparatus according to claim 2 in combination with an elongated tool bar supported transverse to the direction of travel of said vehicle, a plurality of injection shanks supported at spaced intervals along said bar and adapted to be extended downwardly to subsurface points, said manifold conduit being supported generally parallel to said tool bar, and said delivery points being disposed .at the lower ends of said injection shanks thereby permitting uniform fluid injection from each shank regardless of any differential head eflects induced in said manifold conduit by the inclination thereof.

4. An apparatus according to claim 1 in combination with a cap portion attached to said body element, a flexible diaphragm connected to said valve element and sealably secured at its periphery between said cap and body portions, and a threaded insert at the end of said cap portion and comprising an adjustable stop for said loading spring system and having an opening through said insert for communication with said compensating conduit.

5. An apparatus according to claim 4 in combination with a primary and a secondary loading spring disposed and said valve element, said primary spring having spring constant in pounds per inch of deflection of fl'r between the opposing surfaces of said adjustable stop/ being adjusted sothat at zero inlet fluid pressure s, valve element is biased in a closed position by sli} compression of said secondary spring while a clearar A 10 to times that of said secondary spring, said s1 11 exists at one end of said primary spring and whereby a substantially linear variation in volumetric flow rate of the several individual streams from said'regulator with changes in inlet pressure is obtained.

6. An apparatus for the uniform dispensing of a liquid at a plurality of spaced points which comprises a movable vehicle, a liquid storage vessel supported thereon, a liquid inlet thereto, a liquid pump connected at its inlet to said vessel, means for driving said pump at a rate which is a predetermined function of the velocity of said vehicle, an elongated manifold conduit disposed transverse to said vehicle, a conduit opening from the outlet of said pump into an intermediate point of said manifold conduit, an elongated tool bar supported from and transverse to said vehicle, a plurality of injection shanks supported from spaced points along said tool bar and adapted to be extended to subsurface points, a plurality of liquid flow dividers, said dividers comprising a body element having a central fluid inlet channel and a plurality of lateral orifices opening therefrom, a movable valve element disposed within said inlet channel, a hollow cap element sealably secured to said body element, a flexible diaphragm secured at its periphery and disposed in a transverse position between said cap and body elements and attached at its center to said valve element, a loading spring system disposed within said cap element and adapted to bias said valve element toward a position at which the inlet ends of said orifices are sealed, means for connecting said inlet channels to said manifold conduit whereby liquid pressure therein tends to move said valve element against said loading spring system and open said orifices, a plurality of conduits connecting the outlet end of each of said orifices to one of said plurality of injection shanks, a compensating liquid reservoir disposed on said vehicle, and a compensating conduit connecting the lower part of said reservoir with the cap element of each of said liquid flow dividers, said compensating reservoir and conduits containing a liquid having a low volatility and substantially the same specific gravity as that of the liquid being dispensed whereby the net liquid pressure acting on said valve element and diaphragm to open said orifices and the liquid flow rate therethrough is substantially unaffected by the inclination of said tool bar and manifold conduit from the horizontal.

7. An apparatus according to claim 6 wherein said compensating liquid reservoir is located at a level whereby it is adapted to be filled with said compensating liquid to a level substantially the same as the level of said diaphragms in said flow dividers when the manifold conduit is in a horizontal position.

8. An apparatus according to claim 6 wherein said means for driving said pump comprises a variable direct drive between the pump impeller and a wheel attached to said vehicle and riding in contact with the ground whereby a proportionately greater rate of'liquid is pumped as the vehicle speed is increased.

9. An apparatus according to claim 6 wherein said cap element is provided at its end opposite from said body element with a threaded adjustable insert having an opening through which said compensating conduit opens into said cap element, said loading spring system comprising a primary and a secondary loading spring concentric with each other and extending substantially between the inside surface of said threaded insert and said valve element, said primary spring having a constant in. pounds per inch deflection of between about 10 and about 100 times that of said secondary spring, and said threaded insert being adjusted and locked in a position so that with a zero liquid pressure in said inlet channel the secondary spring lightly seats said valve element in the closed position and a clearance exists at one end 'of said primary loading spring whereby a substantially linearvariation in liquid flowrate to each injection shank with applied liquidpressure is obtained.

. 10. An apparatus for dividing a fluid stream into a plurality of fluid streams bearing a predetermined volumetric flow rate relation to each other which comprises a pressure resistant body element provided with a fluid inlet channel extending therethrough and a plurality of orifices opening from said channel through said body element, a valve element movably disposed in said inlet channel, a loading spring system biasing said valve element into a position closing said orifices whereby the pressure of fluid supplied said inlet channel from said manifold conduit tends to move said valve element and open said orifices and permit flow therethrough, a plurality of conduit-s connecting the outlet ends of said orifices to fluid delivery points, said loading spring system comprising a primary loading spring having a constant of between 10 and times that of a secondary loading spring and which is adjusted so that said secondary spring lightly seats said valve element and relieves said primary spring of compression with zero applied fluid pressure whereby the delivery rates are substantially linear with changes in inlet pressure.

11. An apparatus for dividing a liquid stream into a plurality of liquid streams having a predetermined flow rate relation which comprises a body element having a central fluid inlet channel and a plurality of lateral orifices opening therefrom, a movable valve element disposed within said inlet channel, a hollow cap element sealably secured to said body element, a flexible diaphragm secured at its periphery and disposed in a transverse position between said cap and body elements and attached at its center to said valve element, a loading spring system disposed within said cap element and adapted to bias said valve element toward a position at which the inlet ends of saidorifices are sealed, said loading spring system comprising a primary loading spring having a constant of between 10 and 100 times that of a secondary loading spring and which is adjusted so that said secondary spring lightly seats said valve element and relieves said primary spring of compression with zero applied fluid pressure whereby the delivery rates are substantially linear with changes in inlet pressure, a source of liquid under pressure communicating with said inlet channel whereby liquid pressure therein tends to move said valve element against said loading spring system and open said orifices, means for applying to the space within said hollow cap a fluid pressure to compensate for hydrostatic head effects of the source of fluid, and a plurality of conduits connecting the outlet ends of said orifices to a plurality of delivery points.

12. An apparatus for delivering from a single stream under pressure a plurality of fluid streams at different elevations which comprises a fluid storage vessel, a fluid inlet to said vessel, an elongated manifold conduit, means for supplying fluid from said vessel to said manifold conduit, a pluralityof fluid divider and fiow regulators, each of said regulators comprising a pressure resistant body element provided with a fluid inlet channel extending therethrough and a plurality of orifices opening from said ch annel through said body element, means connecting each inlet channel to said manifold conduit at different positions along the length of said manifold conduit, a valve element movably disposed in each inlet channel, a loading spring system biasing said valve element into a position closing said orifices whereby the pressure of fluid supplied said inlet channel from said manifold conduit tends to move said valve element and open said orifices and permit flow therethrough, a plurality of conduits connecting the outlet ends of said orifices to fluid delivery points, a compensating fluid reservoir, and a compensating fluid conduit connecting said reservoir with each of said fluid regulators at points on the opposite side of said valve elements from said fluid inlet thereby applying to said valve element a differential head of compensating fluid substantially equal and opposite to the differential head of fluid'being.dispensed'insaid manifold conduit when said 13 manifold conduit is inclined from the horizontal so that the net fluid pressure tending to move said elements is independent of such inclination.

13. An apparatus according to claim 12 in combina* tion with a primary and a secondary loading spring dis posed between the opposing surface of an adjustable stop and said valve element, said primary spring having a spring constant in pounds per inch of deflection of from 10 to 100 times that of said secondary spring, said stop being adjusted in position relative to said body element so that at zero inlet fluid pressure said valve element is biased in a closed position by slight compression of said secondary spring while a clearance exists at one end of said primary spring and whereby a substantially linear variation in volumetric flow rate of the several individual streams from said regulator with changes in net differential pressure across said valve element is obtained.

14. An apparatus for delivering a plurality of liquid streams of predetermined flow rate relation at a plurality of diflerent elevations without hydrostatic head effects which normally aflYect the liquid flow rate which comprises an elongated manifold conduit disposed along an incline, a liquid supply conduit opening thereinto, a plurality of liquid flow dividers disposed along the length of said manifold conduit, said dividers comprising a body element having a central fluid inlet channel and a plurality of lateral orifices opening therefrom, a movable valve element disposed within said inlet channel, a hollow cap element sealably secured to said body element, a flexible diaphragm secured at its periphery and disposed in a transverse position between said cap and body elements and attached at its center to said valve element, a loading spring system disposed within said cap element and adapted to bias said valve element toward a position at which the inlet ends of said orifices are sealed thereby, means for connecting said inlet channels to said manifold conduit whereby liquid pressure therein tends to move said valve element against said loading spring system and open said orifices, a plurality of conduits connecting the outlet ends of said orifices to a plurality of liquid delivery points, a compensating liquid reservoir disposed along the length of said manifold conduit, and a compensating conduit connecting said reservoir with each cap element of each of said liquid flow dividers, said compensating reservoir and compensating conduits containing a liquid of low volatility and having substantially the same specific gravity of that being dispensed whereby the net liquid pressure acting on said valve element and diaphragm to open said orifices and the rate of liquid flow induced thereby is substantially unaifected by the inclination of said manifold conduit.

References Cited in the file of this patent UNITED STATES PATENTS