US 3670962 A
The present control structure is a centrifugal governor operated relatively low pressure diaphragm valve for a wheeled liquid applicator including a tank for liquid under applied air pressure, the governor being driven from a ground wheel of the applicator by a friction wheel-flexible cable drive, or a belt and pulley drive, or the like. This structure controls the applicator nozzle pressure so that the output, in gallons per minute, is proportioned to the speed, thereby providing a constant gallons per acre output, regardless of the speed. An adjustable drive assembly including a friction wheel-cone provides means for varying the rate of fluid output.
Claims available in
Description (OCR text may contain errors)
United States Patent Johnston 1 June 20 1972 [s4] FLOW CONTROL ASSEMBLY AND 2,757,044 7/1956 Gerbracht ..239/1s7 x METHOD 2'322'333 52322 3322' @3313? rg X 1 8" Johnston Decatur, 3,409,033 11/1968 Johnston ..137/51 73 A'e: DecaturFoun &MnhlneCo.ln. 1 sslgn e Decatur Ala dry c c Primary Examiner-M. Henson Wood, Jr.
Assistant Examiner-Michael Y. Mar  Fil d: N 19, 1969 Attorney-Kingsland, Rogers, Ez/ell, Eilers & Robbins  Appl. No.: 877,977 ABSTRACT  U 8 Cl 239/62 137/51 222/177 The present control structure is a centrifugal governor 239/156 251/282 operated relatively low pressure diaphragm valve for a  Int Cl 1505b 3/16 wheeled liquid applicator including a tank for liquid under ap-  Fie'ld 156 157 plied air pressure, the governor being driven from a ground 239/1 57 1 7 wheel of the applicator by a friction wheel-flexible cable drive, 251/282 or a belt and pulley drive, or the like. This structure controls the applicator nozzle pressure so that the output, in gallons per minute, is proportioned to the speed, thereby providing a  Rem-ewes cued constant gallons per acre output, regardless of the speed. An
UNITED STATES PATENTS adjustable drive assembly including a friction wheel-cone pro- 2 826 215 3/1958 wolfslau at al 251/282 x v1des means for varying the rate of fluid output. 2:586:256 2/1952 Quarles ..239/1 56 x 8 Claims, 13 Drawing Figures PATENTEnJunzo I972 I 3,670,962
sum 1 or s Hz INVENTOR: DOUGLAS JoHA/sTo/v,
FLOW CONTROL ASSEMBLY AND METHOD BACKGROUND OF THE INVENTION l. Field of the Invention The present invention relates generally to flow control, and more particularly to a novel flow control assembly for and a novel method of controlling the fluid pressure on nozzles or orifices in an applicator so that the output rate of the applicator per acre remains constant, regardless of the ground speed of the applicator.
The present invention, preferably a ground wheel actuated pressure control, but adaptable to power take-off, is especially suited for the application of all types of agricultural chemicals such as nitrogen fertilizer solutions, mixed liquid fertilizer solutions, aqua ammonia, suspension fertilizers, slurry fertilizers, herbicides, insecticides, fungicides, fumigants, and others.
It is also well suited for controlling the rate of application of water or any other type of liquid where it is desirable to have a constant rate per increment of forward travel regardless of the speed of the vehicle. As an example, the applicationof water, oil, and tar in highway construction could be applied from a tank on a truck at a preselected and fixed rate per foot of highway, regardless of the speed of the truck.
2. Description of the Prior Art This invention provides the first practical means of applying suspension and slurry type fertilizers at a constant rate per acre, regardless of speed. By such means an operator with a trailer-type or a truck-type applicator will be able to cover twenty percent to forty percent more acreage per day than with a machine that would have to be driven at a constant speed, selected on the basis of the maximum speed practical in the roughest and wettest part of the field.
While it is theoretically possible to operate an applicator at a constant speed to get a continuously accurate output rate per acre, certain practical limitations make this all but impossible. Operators frequently encounter unforeseen conditions that make speed reduction mandatory, and safe operation of the machine and sound judgment require gradually slowing the machine down at the end of the rows, unless the farmer takes out of cultivation enough land to provide a slowing down corridor at the end of the rows on all of his fields.
A nationally recognized authority in the development and application of suspension fertilizers has publicly stated that the advantages of using suspension-type fertilizers are well recognized, but that the potential increase in use of thesefertilizers, has been held back due to the limitations of present day application equipment. This authority was referring particularly to the fact that no system presently available provides a means of controlling output proportional to speed. He stated that the necessity for slowing down constant pressure applicators has in many cases so badly over-fertilized certain crops that the plants were either destroyed or stunted, causing the loss of not only the fertilizer, but part of the farmer's crop. The present flow control assembly solves many of the problems now encountered in the application of suspension-type fertil- 12ers.
At present, non-pressure or low pressure liquid fertilizer solutions are applied by means of ground wheel driven positive displacement, variable stroke metering pumps, by centrifugal pump metering systems, and by air pressure systems in which an air compressor maintains a constant air pressure over the liquid in the tank, requiring a fixed and predetermined constant speed for accurate application.
Suspension-type fertilizers contain suspended crystals, sand, and various other types of abrasive and crystalline substances that tend to settle out and solidify during transport and application. The abrasive particles rapidly score cylinders and ruin valves and piston pumps, while in many cases only short periods of time allow sufficient settling out to fill suction lines and strainers and piping to such an extent that centrifugal pumps frequently loose their prime and stop pumping due to the heavy suction load.
The nature of a centrifugal pump is such that relatively minor restrictions in the suction line may cause them to lose their prime completely, and in this condition they will only apply a negligible suction to clean out the line. Self priming pumps cannot be used, because of the settling out and solidification of crystals and trash in the priming cavity.
While an unprimed centrifugal pump might be able to apply a suction equivalent to only two or three inches water pressure to a clogged-up suction line, a pressure of thirty pounds of air over the material will quickly force the sludge out of the line, and if the air is admitted through a tube running the length of the tank near the bottom, it will continuously and vigorously agitate the material by means of holes drilled along the length of the pipe, known as a sparging tube. It is for these reasons that air pressure is now being recognized as the most practical method of application for suspension-type fertilizers.
This invention provides the only known practical means of accurately metering suspension fertilizers at a rate independent of speed with air pressure applicators, and is equally satisfactory for metering any other type of liquid, whether the pressure over the liquid be supplied by air or whether the pressure to the conu'ol assembly be supplied by a pump.
SUMMARY OF THE INVENTION In brief, the present novel flow control assembly comprises a valve assembly including a valve for controlling the flow of liquid from a tank, or the like, to discharge orifices or nozzles on an applicator, an operatively associated centrifugal governor assembly for positioning said valve which is designed so that at a given speed of an applicator the force developed thereby is constant, and an adjustable drive assembly for rotating said governor assembly in proportion to the ground speed of the applicator, so that the output rate of the applicator per acre remains constant, regardless of the ground speed of the applicator.
Hence, an object of the present invention is to provide a novel flow control assembly for and a method of dispensing liquid fertilizers and the like which fulfill the long existing need in the liquid fertilizer art; which accurately meters such liquids so that substantially the same amount is applied per selected ground increment regardless of the operating speed of the applicator; which is rugged in construction and adapted to perform the intended purpose in the dispensing of large gallonages; which are particularly efiective in thus dispensing such agricultural chemicals as nitrogen fertilizer solutions, mixed liquid fertilizer solutions, suspension fertilizers, slurry fertilizers, herbicides, insecticides, fungicides, and others; and which are otherwise adapted to fulfill the objects and advantages sought, the foregoing and other objects and advantages being apparent from the description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic plan view of a simple two-wheeled applicator, showing the present novel flow control assembly operatively mounted thereon;
FIG. 2 is a side elevational view thereof;
FIG. 3 is an end elevational view of the present novel flow control assembly;
FIG. 4 is a plan view thereof;
FIG. 5 is an enlarged horizontal cross-sectional view taken on substantially the line 5-5 of FIG. 3;
FIG. 6 is a further enlarged vertical cross-sectional view taken on substantially the line 6-6 of FIG. 5;
FIG. 7 is a further enlarged fragmentary view of a portion of FIG. 5 showing the friction wheel-cone and its drive pulley;
FIG. 8 is a vertical transverse cross-sectional view taken on substantially the line 88 of FIG. 5;
FIG. 9 is a vertical transverse cross-sectional view taken on substantially the line 9-9 of FIG. 5;
FIG. 10 is a plan view of the spider, parts being broken away for illustration of details, which pivotably supports the governor weights;
FIG. 1 1 is a plan view of the governor spindle;
FIG. 12 is a further enlarged fragmentary view of aportion of FIG. showing the warning bell striker; and
FIG. 13 is a further enlarged cross-sectional view illustrating an alternate structure for powering the governor assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings more particularly by reference numerals, the present novel flow control assembly is designated generally by the reference numeral 20, which broadly includes a valve assembly 22 for controlling the flow of liquid from a tank or other source of supply to discharge orifices or nozzles on an applicator, a centrifugal governor assembly 24, and an adjustable drive assembly 26 for rotating the centrifugal governor assembly 24 (FIG. 5).
The valve assembly 22 includes a casing 28 having an inlet chamber 29 and outlet chamber 30 (FIG. 5). A threaded inlet 31 is provided for the inlet chamber 29 and a threaded outlet 32 for the outlet chamber 30. A partition wall 33 separates the inlet and inlet chambers 29 and 30 in which is formed an opening threadedly receiving an annular valve seat element 35 having a valve seat 36 at one end and a flange 37 at the other end sealingly engaging a gasket 38. An outlet valve 39 is mounted on a diaphragm stem or spindle 40 for movement therewith and for cooperation with the valve seat 36. The stem 40 extends between and through a balance diaphragm 41 at one end and a main diaphragm 42 at the other end, washers 43 engaging the two sides of the former and washers 44 engaging the two sides of the latter. A nut 45 engages the outer washer 43 and an adjustment shim 46, and integral bolt flange 47 engages the outer washer 44. The valve 39 is positioned on the stem 40 by means of a first cone 51, a cone spacer 52, and a second cone 53 on one side, and a valve spacer 54 on the other side. None, or more than one, shim 46 may be used, as required. An outer reduced end 56 of the stem 40 has sliding support in a bushing 57 and an inner reduced end 58 has sliding support in an end plate 60 and is engaged by a thrust cap 61 forming part of the centrifugal governor assembly 24.
The main diaphragm 42 is clamped between the plate 60 and one side of the casing 28 by bolts 63, there being a chamber 64 between diaphragm 42 and plate 60 exhausted to atmosphere by a passage 65. The passage'65 also serves as a drip exit for any liquid that may leak past the diaphragm 42 which warns a user of a leak. The balance diaphragm 41 is clamped between a ring 67 and an inner wall 68 of the casing 28 by bolts 69. A chamber 70 is thus provided which leads into the outlet chamber 30 by a passage 71.
A closure plate 72 forms a wall of the chamber 70, being secured to the casing 28 by bolts 73. The plate 72 supports the bushing 57, as shown in FIG. 5. A threaded plug 74 closes a testing outlet 75. Inlet and outlet hose line fittings 77 and 78, respectively, are shown threaded into the inlet 31 and outlet 32.
The centrifugal governor assembly 24 is operatively mounted in a housing 80 of cylindrical form, one end of which is closed by the plate 60 which is secured thereto by bolts 79 (FIG. 4). Within the housing 80 is a partition wall 81, integral with which are oppositely extending concentric bearing sleeves 82 and 83, respectively, supporting a needle bearing unit 84 and a sealed ball bearing unit 85. A grease seal 86 is provided for the needle bearing unit 84. A governor spindle 87 of varying cross section, FIGS. 5 and 11, is rotatably supported by the bearing units 84 and 85. On the one end of the spindle 87 is secured a friction wheel-cone 88 by a bolt 89, which is an element of the drive assembly 26. On the other side of the wall 81 from the wheel-cone 88 and pinned to the spindle 87 is a governor spider 90 having four pairs of equally spaced arms 91, each pair having aligned openings receiving a pin 92 on which is pivotally mounted a governor weight 93. Freely rotatably mounted on the other end of the spindle 87 is a cam plate follower 95 which is in engagement with cam portions 96 of the weights 93. Adjacent the cam plate follower 95 is a thrust bearing unit 97 which, in turn, is contiguous to the thrust cap 61.
Mounted on the outside of the housing by a threaded post 99 is a warning bell 100. A bell striker or clapper 101 is reciprocably mounted in the wall of the housing 80 and is biased inwardly by a spring 102 into position out of contact with the edge of the bell 100, as shown in FIG. 5. When weights 93 swing too far outwardly, as on too great a speed of the applicator, they strike the bell striker 101 which, in turn, hits the bell to warn the operator. Closing three openings in the wall 81 formed in casting the housing 80 are plastic sealing cups 104 which are employed to prevent grease or oil from the governor assembly 24 from leaking to the friction wheelcone 88.
The adjustable drive assembly 26 includes an oddly shaped housing 106 of the configuration shown in FIGS. 5-7, which includes an end plate portion 105 closing the housing 80, being secured thereto by spaced bolts 107. Slidably mounted in the housing 106 is a spindle housing 108 having a flat side 109 (FIG. 6) against which a thumb screw 110 releasably engages, and an axially extending groove 111 in which is disposed a rack 112. The spindle housing 108 also includes an enlarged end portion 114 disposed in an enlarged end portion 115 of the housing 106, said enlarged portions 114 and 115 having engageable annular shoulders limiting movement of the spindle housing 108 inwardly to the position of FIG. 5. An end plate 116 secured to the housing 106 by bolts 117 limits movement of the spindle housing 108 in the opposite direction. The plate 1 16 has a large central opening 1 18 for a purpose described below. Mounted in the enlarged end portion 114 is a sealed ball bearing unit 120 which rotatably receives a segment of reduced diameter of a powered cable spindle 121, thus also maintaining the spindle 121 against axial movement in respect to the spindle housing 108. At the inner end of the spindle 121 is a supporting needle bearing unit 122 protected by a grease seal 122'. Secured to the inner end of the spindle 121 against movement is a drive pulley 123 having an O ring tire 1240f rubber composition or other suitable material, which is in driving engagement with the wheel-cone 88. At one side of the housing 106 is a boss 125 having a bore 125' into which extends a post 126 (FIG. 6). A calibrated dial 127 is provided which includes a disc member 128 pinned to the upper end of the post 126 and a calibrated disc plate 129 adjustably mounted thereon. A pointer 130 is disposed adjacent the dial 127. Pinned to the post 126 at its lower end and in an enlargement of the bore 125' is a pinion 131 which meshes with the rack 1 12. It will be understood that the thumb screw 110 is loosened to permit adjustment of the position of the spindle housing 108, hence, of the drive pulley 123-in respect to the driven wheel-cone 88, by rotation of the calibrated dial 127 to a selected position. The thumb screw 110 is then re-secured.
A cable cap 133 is secured in the outer enlarged end 1 14 of the spindle housing 108 by screws 134. A cable wire 136 with a square end extends into a square hole in the outer end of the cable spindle 121. A fitting 140 threadedly engages the cap 133 and maintains a sleeve 141 is position extending through the opening 118 in the end plate 116. The sleeve 141 guides the cable wire cover 142 in axial movement of the spindle housing 108. The cable wire 136 and cover 142 are connected to a conventional friction speed sensor wheel 144 (FIGS. 1 & 2). A rubber, or the like, bellows 143 engages the cover 142 and extends through the opening 1 16, as shown, to protect the working parts from water, dirt and other foreign matter. The speed sensor wheel 144 preferably rides on the ground engaging portion of applicator wheels, or the like, but may be mounted to run against the side of a tire or wheel, if, for example, cleats or mud interfere.
FIGS. 1 and 2, the present novel flow control assembly 20 is diagrammatically illustrated operatively mounted on a small two wheel applicator which includes a frame or chassis 151, wheels 152, a tank 153 for liquid fertilizer 154, and the like, under pressure in the tank 153, a spray boom assembly 155, a conduit 157 connecting the bottom of the tank with the flow control assembly 20, and a conduit 158 connecting the flow control assembly 20 with the spray boom assembly 155.
A power take-off driven air compressor 147 is mounted at the front of the chassis 151 which is connected into the tank 153 by a fluid line 148 and sparging tube 149. It will be understood that a safety relief valve and pressure regulator (not shown) are used in the line 148. A centrifugal pump may be used instead of the compressor 147. The speed sensor wheel 144 is mounted on the frame 151 is depending pivotal relation by a bracket unit 160 and a plate 161. A tension spring 162 biases the wheel 144 against the wheel 152 with several pounds force.
A rope operated cut-off ratchet valve 159 is located in the conduit 158, as indicated in FIGS. 1 and 2, between the outlet of the flow control assembly and the boom assembly 155. When the valve 159 is closed, tank pressure acts on the main diaphragm 42 to close the valve 39 and to push the governor weights 93 to the center. This prevents the governor weights 93 from swinging out and ringing the bell 100 at the end of a row in turning around or in travel.
In FIG. 13 a pulley 164 is illustrated as a modified structure for transferring rotation of the wheels 152 to the drive assembly 26. The pulley 164 may be driven in the manner of the pulley 54 shown in FIGS. 1 and 2 of the applicant's U.S. Pat. No. 3,409,033. A cap 165 is secured by screws 166 to the outer enlarged end 114 of the spindle housing 108. A pulley spindle 168 replaces the cable spindle 121, the former being longer than the latter and receiving the pulley 164 on the outer end thereof. A sleeve member 169 is secured to the enlarged end portion 115 of the housing 106 by screws 170. A ball bearing unit 171 is mounted in the sleeve member 169 and receives the spindle 168, as shown. The pulley 164 is secured to the spindle 168 against relative annular movement, but permitting relative axial movement by a spring pin 172 and axial slot 173. A felt ring 174 protects the parts from dust and dirt. Thus, the spindle 168 may be adjusted in and out as the dial setting is changed, but pulley 164 is held in a fixed position by the ball bearing unit 171 and snap rings 176 and 177. A plastic or rubber dust cap 178 to keep water and dust from damaging steel parts is provided.
OPERATION It is clear from the foregoing taken with the drawings that the drive pulley 144, which turns a fixed and definite number of revolutions per revolution of the applicator wheel 152, drives the wheel-cone 88. The relative speed or number of revolutions per minute of the wheel-cone 88 obviously depends upon its radius at the point where it is contacted by the driven pulley 123.
For the position in which the drive pulley 123 is shown in FIG. 5, the dial pointer 130 points to 30 on the dial 127. This is the slowest relative speed at which point the wheelcone 88 turns 0.667 revolutions per turn of the drive pulley 123. Assuming the dial 127 has been freed by loosening the thumb screw 110 and rotated to the left until the numeral 30 is opposite the pointer 130 and tightened, rotation of the dial 127 counterclockwise from 30 to 35, etc., to 100, will bring the drive pulley 123 in a position to drive the wheel-cone 88 at its highest speed, which is 2.28 revolutions per revolution of the drive pulley 123.
With these proportions, if one assigns a dial value of 100 to the maximum speed of the wheel-cone 88 in relation to the drive pulley 123, at which position the former turns 2.28 revolution per revolution of the latter, then at the large diameter of the wheel-cone 88, at which position it turns 0.667 revolutions per revolution of the drive pulley 123, the slow speed of the wheel-cone 88 is 29.3 percent of its maximum speed. Rather than calibrate the dial 127 in fractions, it is calibrated from 30 to 100 and the calibrations represent the relative speed of the wheel-cone 88 in relation to the speed of the drive pulley 123.
As the spindle 87 and spider 90 are rotated as the wheelcone 88 is rotated, the centrifugal force swings out the weights 93 causing cam surfaces 96 to rotate about pins 92 and apply a force to the cam follower 95, which, in turn, through thrust bearing unit 97 and thrust cap 61 applies a force to the diaphragm spindle 40 which tends to lift the valve 39 off the seat 36 to allow the fluid to flow from the inlet chamber 29, which is approximately at tank pressure, to the outlet chamber 30, which communicates through a hose 158 to the nozzles on the boom assembly 155, the entrance pressure of which is approximately equal to that in outlet chamber 30.
Assuming that the control assembly 20 is at rest with the valve 39 closed on the seat 36 with tank pressure of about 30 pounds per square inch in the inlet chamber 29, and with the outlet chamber 30 at atmospheric pressure, having been drained through said nozzles or orifices, the force of the governor assembly 24 on the diaphragm 42 would have to be about 53 pounds to being lifting the valve 39 off the seat 36. This is because in a preferred embodiment the area of the valve 39 (1% inches diameter) is 1.77 square inches, which multiplied by thirty pounds per square inch would give a total force of 53 pounds.
However, the balance diaphragm 41 and its washers 43 are so proportioned that the effective area of this diaphragm 41 is exactly equal to the area of the outlet valve 39 (1.77 square inches). Therefore, while the 30 pound tank pressure applies a closing force of 53 pounds to the valve 39, at the same time it applies an equal and opposite force against the balanced diaphragm 41, so the difference between the tank pressure and the outlet pressure have no efiect whatsoever on the force required to lift the valve 39 off of the seat 36 or to hold it open in any position. The outlet valve 39 is balanced by the diaphragm 41 at any nozzle pressure, since the pressures under the valve 39 and above the diaphragm 41 are equalized by passage 71.
With reference to previously referred to Johnston U.S. Pat. No. 3,409,033, the diaphragm 41 is used to balance the outlet valve 39 exactly in the same manner that the piston 100 (FIG. 11 of the patent) is used to balance the outlet valve 92. A piston could not be used in place of the diaphragm 41 to balance the outlet valve 39 for this control assembly 20,
because it is designed to handle highly corrosive and abrasive fluids containing sand, crystals, and other suspended solids that would quickly score and ruin a piston and the piston packings. Further, this control assembly 20 is designed to operate at maximum pressures of around 75 pounds per square inch, for which conventional diaphragms have adequate strength. On the other hand, the ammonia control shown in said US. Pat. No. 3,409,033 is designed for operating pressures of anhydrous ammonia, which may reach two hundred and fifty pounds per square inch, that would make the use of a diaphragm unsafe. It is to be noted that the use of diaphragms in this control assembly 20 has completely eliminated the necessity for seals or packings that might wear and leak.
Assuming that the control assembly 20 is functioning, the orifice or noule pressure is chamber 30 acting on the main diaphragm 42 will exactly balance the force developed by the governor weights 93 acting against the nozzle pressure on diaphragm 42. If the speed of the governor assembly 24 is increased due to the increase in speed on the applicator 150, or if the speed of the governor assembly 24 is increased by increasing the dial 127 setting, the speed of the applicator remaining constant, the force applied by the governor as-,
sembly 24 to the diaphragm spindle 40 to raise the valve 39 further off its seat 36 will raise this valve 39 off the seat 36 increasing the flow through the valve assembly 22 and the pressure in chamber 30 until the nozzle pressure and the pressure in chamber 30 have increased enough to act across the main diaphragm 42 to balance the increased force of governor as sembly 24.
Therefore, it can be readily seen that an increase in speed of the applicator 150 or increase in the dial 127 setting will increase the flow and pressure on the nozzles or orifices of the boom assembly 155, and conversely a decrease in applicator 150 speed or dial 127 setting will decrease the flow and pressure on said orifices or nozzles.
Since the governor assembly 24 in this control assembly 20 is for practical purposes identical to the governor shown in the control assembly in US. Pat. No. 3,409,033, the force exerted by governor assembly 24 against the spindle 40 is a constant times the square of the speed (see col. l0, equation [11 of said patent). As explained in said patent, which is incorporated herein by reference, the force exerted by the governor assembly 24 is independent of the position of the weights 93, determined. by the position of the outlet valve 39, and dependent only on the speed of the governor assembly 24.
ll a maximum speed were established for the governor assembly 24 and a maximum tank'pressure were established for the tank 153, the area of the diaphragm 42 should be so established that the area of the diaphragm 42 acted over by the maximum tank pressure would exactly equal the maximum force of the governor assembly 24. From this, logic would make it necessary to establish the speed relationship of the tire friction wheel 144 so that when the applicator 150 is traveling at the maximum speed desired, the cable speed, with the dial 127 set on 100, would be such that the governor assembly 24 is turning at the maximum established revolutions per minute, and developing a force sufficient to exactly balance the tank pressure on the diaphragm 42.
At 860 RPM, the governor assembly 24 develops a force of approximately 95.5 pounds. in order to exactly balance the force of the governor assembly 24 with a maximum tank pressure of thirty pounds per square inch, the diaphragm 42 should have an effective area of 3.18 square inches, i.e., 95.5 divided by 30.
If the maximum desired speed of the applicator 150 with a control dial 127 set on 100 is assumed to be 3.51 miles per hour, the speed of the control cable 136 should be 107.5 revolutions per minute for each mile per hour ground speed, which would mean the cable 136 would turn 377 (3.51 X 107.5) revolutions per minute at 3.51 miles per hour. At maximum dial setting, it would turn the governor assembly 24 at 860 (377 X 2.28) revolutions per minute, since at a dial setting of 100, the wheel-cone 88 turns 2.28 revolutions per minute for each revolution of the drive pulley 123.
Since it is obvious that the force of the governor assembly 24 cannot exceed the tank pressure times the area of the diaphragm 42 because, in this case, the governor weights 93 would continue to swing out with nothing to stop them and ultimately begin to drag against the inside of the housing 80 which would make the control assembly 20 inaccurate and very likely damage it severely, any increase in the maximum selected governor assembly 24 speed must be accompanied by an increase in tank pressure.
Since the force of the governor assembly 24 is proportional to the square of the speed, the increase in tank pressure required must also increase with the square of the speed. For example, if the governor assembly 24 speed were increased 50 percent from 860 to 1,290 RPMs, the tank pressure would have to be increased by 1.5 squared, which would be 2.25, and 2.25 times the original 30 pounds per square inch pressure would be 67.5 pounds per square inch pressure required for increasing the governor assembly 24 speed to one hundred and 50 percent of its original speed of 860 RPM.
As explained above, the speed relationship between the governor spindle 87 and the flexible cable wire 136 is proportional to the dial 127 setting. lf a setting 100 gives a governor assembly 24 speed of 860 RPM at 3.51 miles per hour, than a dial 127 setting of 50 would give a governor assembly 24 speed of 430 RPM at 3.51 miles per hour. Therefore, it is seen that as the setting is decreased, the applicator 150 speed may be increased, and at a dial 127 setting of 50, the allowable speed of the applicator 150 would be 7.02 miles per hour, without exceeding the maximum governor assembly 24 speed of 860 RPM which, in turn, is based on a tank pressure of 30 pounds per square inch.
miles per hour with the dial set on is exactly double the output rate per acre at 7 miles per hour with the dial set on 50. Another way of saying this is that with a fixed and limited tank pressure and a given size of nozzle, the maximum rate of flow obtainable is fixed in gallons per minute and distributing this amount at 3.5 miles per hour applies twice as much to the ground as it does at 7 miles per hour.
In selecting the nozzle size one needs, the operator first determines the maximum speed at which he will operate. If he selects a maximum speed of 7 miles per hour and wishes to apply 60 gallons per acre, he would determine that for a speed of 7 miles per hour, his dial 127 cannot be set above 50 and he would select KSS 40 nozzles. To give him 60 gallons per acre, he would set the dial 127 at 41.5 X 0.415 60.1), which would give him 60 gallons per acre, at any speed between 7 and 1.3 miles per hour. The minimum speed is merely the speed required to overcome the effect of gravity on the governor weights 93. Were there no limit to the tank pressure available and no limit to the pressure capability of the control assembly 20, one could operate the control assembly 20 at any speed or dial 127 setting desired as long as one were above the minimum allowable speed.
The governor assembly 24 as above pointed up, develops a force on the diaphragm spindle 40 proportional to the square of the governor assembly 24 speed which is a function of the ground speed with a given dial 127 setting. Therefore, for a given dial 127 setting, the governor assembly 24 force is proportional to the square of the ground speed. Inasmuch as the pressure on the diaphragm 42 multiplied by the area of the diaphragm 42 is equal to the governor assembly 24 force, it follows that the pressure on the diaphragm 42 is proportional to the force of the governor assembly 24, the diaphragm 42 area being constant, and the pressure is, therefore, also pro-' portional to the square of the ground speed.
Since the pressure on the diaphragm 42 is also substantially the pressure on the nonles or orifices of the boom assembly 155 the flow in gallons per minute through said nozzles or orifices is proportional to the ground speed, for the flow through nozzles or orifices is proportional to the square root of the pressure, see mathematical explanation in said US. Pat. No. 3,409,033, column 11, equation VII.
For a fixed given ground speed, the RPM of the governor assembly 24 is proportional to the dial 127 setting, but since the force developed by the governor assembly 24 is proportional to the square of the Speed, and since the pressure developed on the diaphragm 42 is proportional to the governor assembly 24 force, the pressure is proportional to the square of the dial 127 setting, and the flow through said orifices and nozzles is directly proportional linearly to the dial setting.
Hence, it is clear that the current invention provides a control assembly 20 that regulates the nozzle or orifice pressure so that the output rate per acre remains constant regardless of speed, and provides a means of adjusting the output rate with a dial such that the output rate is proportional to the dial 127 setting.
A further word about the warning bell 100 is appropriate. If the pressure supplied to the control assembly 20 should become too low in chamber 29 above the valve 39 so that the flow through the valve 39 is not sufficient to maintain adequate pressure on the diaphragm 42, which is approximately the same as the pressure on the nozzles of the boom 155, the governor assembly 24 will continue to open the valve 39, allowing the governor weights 93 to swing out until they being striking the bell clapper 101. The clapper 101 is driven out against the bell 100, which rings and warns the operator that there is insufiicient tank pressure to maintain accuracy of the control assembly 24.
Conversely, if the tank pressure has been maintained at the proper value, and the operator drives the applicator above the maximum recommended speed, the governor assembly 24 force will increase beyond its normal value, for which the tank pressure is set, and it will again swing the weights 93 out to ring the bell 100.
With reference to FIGS. 1 and 2, there is diagrammatically shown an air pressure applicator 150. It is understood that an air compressor is mounted on the tongue of the applicator 150 which may be driven through a slip tube-type of propeller shaft that has a universal joint at each end, and is connected to the power take-off of the pull tractor. The compressor discharge line is connected to a pressure regulator attached to the tank 153 in conventional manner and by this means maintains a constant and pre-set pressure in the tank.
It is also conceived that a power take-ofi driven centrifugal pump may be mounted on the front of the tongue of the applicator 150, in which case, the outlet of the tank 153 would be connected to the inlet of the centrifugal pump and the discharge of the centrifugal pump would be connected to the inlet 31 of the control assembly 20. One may interpose a bypass or a relief valve between the discharge of the pump and the control assembly which may be used to limit the pressure admitted to the control assembly 20 and/or also for returning by pass fluid to the tank 153 for agitation.
It is clear from the foregoing that there have been provided a novel structure for and a novel method of fulfilling the objects and advantages sought therefor.
It is to be understood that the foregoing description and the accompanying drawings have been given by way of illustrau'on and example. It is also to be understood that changes in form of the several parts, substitution of equivalent elements or steps, and rearrangement of parts or steps, which will be readily apparent to one skilled in the art, are contemplated as within the scope of the present invention, which is limited only by the claims which follow.
What is claimed is:
1. In combination, a centrifugal governor operated diaphragm valve for controlling the spray nozzle pressure of a liquid applicator so that the output in gallons per minute is proportional to the applicator speed to provide a constant gallons per acre output and the like, regardless of the speed of the applicator within its predetermined operating range comprising a flow passage for liquids, a valve in said passage, a pressure balancing yieldable diaphragm operatively connected with said valve for movement therewith, said balancing diaphragm having an effective area subjected to inlet pressure substantially equal to the effective area of said valve subjected to inlet pressure, and an effective area subjected to outlet pressure substantially equal to the effective area of said valve subjected to inlet pressure, a centrifugal governor operatively connected with said valve for positioning the same in accordance with the speed of an applicator, and means for effecting operative rotation of said governor including rotatable means adapted to be driven at speeds proportional to speeds of an applicator on which said valve is mounted.
2. The combination of claim 1, in which said means for effecting operative rotation of said governor further includes adjustable means to vary the preselected gallonage per acre, said adjustable means comprising a friction wheel-cone operatively connected to said governor for movement therewith, and a driven drive pulley operatively engaging said friction wheelcone, at least one of said pulley and wheel-cone being adjustable in respect to the other to vary preselected gallonage per acre, said pulley being adjustable, and a calibrated rotatable disc member integrated with said pulley, rotation of said disc member in preselecting the required gallonage effecting the required movement of said pulley in respect to said wheelcone, means for driving said pulley including rotatable means adapted for operative relation with wheels and the like of an applicator, said rotatable means comprising a friction speed sensor wheel adapted to engage the wheel tire of an applicator, said speed sensor being operatively connected to said pulley, and alarm means operatively mounted to warn a user that the governor is swinging on a radius greater than its preselected operating radius.
3. In combination a centrifugal governor operated diaphragm valve for controlling the spray nozzle pressure of a liquid applicator so that the output in gallons per minute is proportional to the applicator speed to provide a constant gallons per acre output and the like, regardless of the speed of the applicator within its predetermined operating range comprising a flow passage for liquids, a valve in said passage, a centrifugal governor operatively connected with said valve for positioning the same in accordance with the speed of the applicator, and means for effecting operative rotation of said governor including rotatable means adapted to be driven at speeds proportional to speeds of the applicator on which said valve is mounted and adjustable means to vary the preselected gallonage per acre.
4. The combination of claim 3, in which said adjustable means comprises a friction wheel-cone operatively connected to said governor for movement therewith, and a driven drive pulley operatively engaging said friction wheel-cone, at least one of said pulley and wheel-cone being adjustable in respect to the other to vary preselected gallonage per acre.
5. The combination of claim 4, in which said pulley is adjustable, and a calibrated rotatable disc member integrated with said pulley, rotation of said disc member in preselecting the required gallonage effecting the required movement of said pulley in respect to said wheel-cone.
6. The combination of claim 5 and including means for driving said pulley including rotatable means adapted for operative relation with wheels and the like of an applicator.
7. The combination of claim 6, in which said rotatable means comprises a friction speed sensor wheel adapted to engage the wheel tire of an applicator, said speed sensor being operatively connected to said pulley.
8. In combination, a centrifugal governor operated diaphragm valve for controlling the spray nozzle pressure of a liquid applicator so that the output in gallons per minute is proportional to the applicator speed to provide a constant gallons per acre output and the like, regardless of the speed of the applicator within its predetermined operating range comprising a flow passage for liquids, a valve in said passage, a centrifugal governor operatively connected with said valve for positioning the same in accordance with the speed of the applicator, an alarm means operatively mounted to warn a user that the governor is swinging on a radius greater than its preselected operating radius, and means for effecting operative rotation of said governor including rotatable means adapted to be driven at speeds proportional to speeds of the applicator on which said valve is mounted.
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