US2922372A

US2922372A - Pumping station

Info

Publication number: US2922372A
Application number: US539348A
Authority: US
Inventors: Oscar H Dorer
Original assignee: Worthington Corp
Current assignee: Worthington Corp
Priority date: 1955-10-10
Filing date: 1955-10-10
Publication date: 1960-01-26
Anticipated expiration: 1977-01-26

Description

Jan. 26, 1960 o. H. DORER PUMPING STATION 4 SheetsSheet 2 Filed Oct. 10, 1955 OSCAR H. Q O B ER F G. 2 ,4 T

4 Sheets-Sheet 3 QEENEB )1. M

Jan. 26, 1960 DORER PUMPING STATION Filed Oct. 10, 1955 [HI gli IWAIH 'IIII/Iilllill FIG OSCAR H Jan. 26, DORER 2,922,372

PUMPING STATION Filed Oct. 10, 1955 4 Sheets-Sheet 4 F|G.7 FIG. 8

OSCAR H.DORER INVEN TOR.

FIG. 6 W

United States Patent PUNIPING STATION Oscar H. Dorer, East Orange, N.J., assignorto Worthington Corporation, Harrison, N.J., a corporation of Delaware Application October 10, 1955, Serial No. 539,348 12 Claims. Cl. 103-11 The present inventionrelates to a pumping station and more particularly to novel means for controlling the output or capacity of said pumping station.

In accordance with the present invention novel means are provided for controlling the output or capacity of the pumping station in response to the discharge head of the station where the discharge head varies by reason of an external factor on the pumping station, for example, the varying level of the river into which the pumping units of the station discharge.

The invention will be better understood from the following description when considered in connection with the accompanying drawings forming a part thereof and in which:

Figure 1 is a perspective view of a pumping station embodying the present invention.

Figure 2 is a view of a single pumping unit in the pumping station embodying the novel control means of the present invention.

Figure 3 is an elevational sectional view taken on line 3-3 of Figure 4 of the actuating means for controlling the speed of a pumpingunit embodied in the present invention.

Figure 4 is a transverse section taken on line 4-4 of Figure 3.

Figure 5 is a diagrammatic view of the cam switches and electrical circuit embodied in the present invention.

Figure 6 is a view of the cam switches for placing in operation the pumping units embodied in the present invention showing their angular displacement with respect to one another.

Figure 7 illustrates the position of a cam switch in Figure 6 before it has contacted the mercury switch which closes the electrical circuit of a pump.

Figure 8 illustrates the position of the cam switch of Figure 7 after'the electrical circuit of the pump is. energized.

Referring to Figure 1, the reference numeral 10 designates a pumping station having a plurality of centrifugal pumps 11 disposed therein. Each pump 11 is provided with a. suction line 12 in communication with the station suction reservoir 13 and a discharge line 14 in communication with a syphon 15. The lower end of discharge leg 16 of a syphon is disposed in a weir box or sealing vessel 17 in communication with the pumping station dis charge opening or outlet 18. The outlet 18 is in communication with a body of water, for example, a river (not shown).

Referring to Figure 2, each pump 11 is connected through gearing means 19 to a magnetic drive 20 driven by a constant speed prime mover, for example, a synchronous electric motor 21.

Magnetic drive 20 provides means for increasing or decreasing the pump speed while allowing the prime mover to operate at a constant speed. The variation in the pump speed is accomplished by the amount of excitation to the magnets forming part .of the pump driving means. The excitation supplied from a three phase 2,922,372 Patented Jan. 26, 1960 ice rectifier (not shown) incorporated in the magnetic drive control which rectifier is actuated in response to an electronic control 22 connected to drive 20 by

electrical conduits

23 and 24. Control 22 receives signals through electrical conduits 25 from a small potentiometer rheostat 26 connected to each pump 11. Potentiometers 26 control the output of electronic tubes (not shown). The resistance of the potentiometer rheostats 26 is varied by a potentiometer actuating means 27 (Fig. 3), disposed in a housing 28, and responsive to changes in a fluid level, as hereinafter described.

Referring to Figures 3 and 4, the actuating means 27 is provided with a rotatable shaft 29 extending through the opposite side Walls of the housing 28 and supported in ball bearings 30. A sprocket wheel 31 is fixed on one end of shaft 29 and engages the links of a chain 32 (Fig. 2) having a weight 33 (Fig. 2) on one end thereof and a float 34 (Fig. 2) on the other end thereof. Float 34 is arranged in a casing 35 (Fig. 2) in communication with suction reservoir 13 to register the mean level therein at all times. As the fluid level rises and falls in the reservoir, by the action and counter-action of the float 34 and weight 33, sprocket wheel 31 and shaft 29 will be rotated in one or another direction, as hereinafter described.

Shaft 29 is provided with a roller 38 disposed in an elongated slot 37 of a circular shaped cam 36 to permit horizontal movement of the cam with respect to the shaft, as hereinafter described. A longitudinally extending rack 39 adapted to mesh with pinions 40 fixed on

potentiometer shafts

41 and 42 is fixed to cam 36 adjacent the outer periphery thereof.

Shafts

41 and 42 have pointers 43 fixed thereto adapted to engage the potentiometer rheostats 26 to vary the resistance thereof. Variation of the potentiometer resistance of a pump 11 is transmitted through lines 25 (Fig. 2) to electronic control 22, and through

lines

23 and 24 to the magnetic drive Ztl of a pump to vary the excitation thereof to change the speed of the pump.

A transverse rephasing shaft 50 is disposed in housing 28 adjacent shaft 29. Shaft 50 is rotatably mounted in ball bearings 51. A rephase or crank arm 52 is fixed on the shaft 50 and is provided with a crank pin 53 at the outer end thereof.

Gears

54 and 55 are fixed on the opposite ends of pin 53 and are adapted to mesh with

gears

56 and 57 respectively, freely mounted for rotation on rephase shaft Sit.

Gears

56 and 57 are adapted to mesh with

gears

53 and 59 respectively, on shaft 29. Gear 59 is rigidly fixed to shaft 29 while gear 58 is freely mounted thereon for rotation with respect to the shaft.

Apitman arm 60 is rigidly connected to gear 58 and provided with a cam roller 61 on the outer end thereof adapted to slide in a D-shaped slot or track 62 disposed in cam 36 adjacent its circumference.

Referring to Figure 5, shaft 29 is provided with a plurality of step-down gears 63 adapted tornesh with pinions 64 fixed on a shaft 65 extending parallel to shaft 29. Each pinion 64 is provided with. an arcuate arm 66 connected thereto. The other end of arm 66 is provided with a pin disposed in a slot 63 of a circular cam 67 to activate said cam. Cams 67 are carried on a shaft 69 extending parallel to shaft 65 and are angularly displaced from one another thereon as shown in Figures 6 and 7. Each cam is adapted to contact a mercury switch 70 in the electrical circuit of a pump motor 21 to close the circuit. The mercury switch when closed permits the circuit of a motor to be energized through a solenoid switch disposed therein. Slots 68 in earns 67 are of different width from one another in order to energize a respective motor at different time intervals, as described in the operation herein. A gear 71 is adapted to engage a worm gear on shaft 69 to provide a friction device to hold the a cams in a fixed angular position after they are rotated, as hereinafter described.

Potentiometer recycling means 75 (Figs. 2 and 4) are provided for motors 21 to increase or decrease the speed of a pump 11 in operation, in response to the delivery pressure in its respective syphon 15. Recycling means 75 comprises a rotatable shaft 76 which extends into housing 28 adjacent shaft 50, a sprocket wheel 77 fixed on the shaft outside the housing and a gear 78 fixed thereon in the housing. Gear 78 is adapted to mesh with a gear 79 fixed on shaft 50. A chain 80 (Fig. 2) is carried on sprocket wheel 77 and has a weight 81 (Fig. 2) and a float 82 (Fig. 2) on the opposite ends thereof. Float I 82 is arranged in a mercury filled reservoir 83 (Fig. 2) having a fluid pressure line 84 in communication with pipes 85 connected to syphons 15. Valves 86 are disposed in pipes 85 to close ofr an inactive pump while a valve 87 is disposed in line 84 to close off the pumping station when not in operation. Syphon breaker valves 88 are disposed in syphons to prevent backflow of fluid from the river level to the pump when the pump is not in operation. All of the valves may be provided with solenoid switches (not shown) in the pump electrical circuit for operation thereof when a pump is placed in operation.

In operation, as fluid passes into suction reservoir 13 of the pumping station the liquid level thereof will rise and will cause float 34 to move upwardly in casing 35, and weight 33 connected to the other end of chain 32, to move downwardly. Since chain 32 is carried on sprocket wheel 31 this action of the float and weight will cause the sprocket wheel to rotate counter-clockwise. The rotation of sprocket wheel 31 causes shaft 29 to rotate therewith. Shaft 29, in turn rotates stepdown gears 63 which mesh with pinions 64 on shaft 65. Pinions 64 in turn rotate arcuate arms 66 thereby causing the arm pins disposed in slots 68 to move therein. When the arm pin of the first pump to be placed in operation has moved its respective width in its slot it moves its respective cam 67 about shaft 69. When the cam 67 of the pump is rotated a sufiicient distance, it will contact the mercury switch 70 in the pump circuit and close the circuit. The solenoid switch therein will then energize the pump motor 21 and hence one of the pumps 11 will be started. The actuated pump 11 will then take a suction on the fluids in the suction reservoir 13 and discharge it through pumping station outlet 18.

Thereafter, the pump will adjust its speed so that the pumping rate equals the inflow rate to the suction reservoir. The pump speed will be adjusted in accordance with the current rise and fall of the fluid level in the suction reservoir which will cause float 34 to move upwardly or downwardly in casing 35. This action of float 34 is transmitted through chain 32 to sprocket wheel 31 thereby rotating shaft 29 and gear 59 fixed to the shaft. Gear 59 in turn rotates gear 57 on shaft 50, and gear 57 engages gear 55 to rotate gear 55 and crank pin 53 to which it is attached, and gear 54 fixed to the other end of the crank pin. Gear 54 in turn meshes with gear 56 freely mounted on shaft 50 to turn gear 56 about said shaft. Gear 56 transmits rotational movement to gear 53 and pitman arm 60 connected thereto. The rotation of pitman arm 60 with respect to shaft 29 slides cam roller 61 in the D-shaped slot 62 of cam 36. The movement of the cam roller 61 causes the cam 36 to slide back and forth on roller 38 disposed in cam slot 37 thereby moving the rack 39 connected thereto. Rack 39 in turn moves the potentiometer rheostat 26 on

shafts

41 and 42 so that the pointer 43 fixed to the shafts contacts the potentiometers at varying positions to vary the resistance therein. The variation of the potentiometer resistance is transmitted through electrical conduits 25 to electronic control 22, and through electrical conduits 23 the excitation of the magnetic drive and thereby vary and 24 to the magnetic drive 26 of the pump 11, to vary the speed of the actuated pump 11to that required so that the pumping rate equals the inflow rate to the suction reservoir.

When the first pump or unit in operation has attained its full speed and there is a further increase in the inflow rate to the suction reservoir 13, and consequently a rise in the liquid level therein, a second pump will be started in operation at full speed;

The second pump is started in operation in the same manner asthat above-described for placing a first pump in operation. That is, a rise in the fluid'level in the suction reservoir 13 will cause float 34 to move upwardly in casing 35 so that the weight 33 will move downwardly. This will cause sprocket wheel 31 to turn in a counterclockwise direction to' thereby'rotate shaft 29 and the second pump pinion 64 on shaft 65 through engagement with the stepdown gear 63 of shaft 29. Pinion 64 in turn will rotate arcuate arm 66. Arm 66 of the second pump is turned or rotated by pinion 64 to move its arm pin in slot 68 of the second pump cam. Since slot 68 is wider than the slot 68 disposed in cam 67 of the first pump, the arm pin will have a greater distance to travel in theslot and hence will not actuate the cam 67 to start the second pump as soon as the first pump. This is to permit the fluid level in the suction reservoir 13 to rise a predetermined amount above the full pumping capacity of the first pump on theline so that when the second pump is placed in operation there will not be a quick lowering of the fluid level in the suction reservoir to cut out operation of the second pump. This avoids the condition of continuous starting and stopping of the successive pump placed in operation, in this case, the second pumping unit. When the fluidlevel in the reservoir has risen above the predetermined amount; which exceeds the full speed pumping capacity of pump number 1, the arm pin will contact cam 67 of the second pump to actuate the cam so as tocontact the mercury switch 70 in the second pump circuit to, thereby start the pump motor 21 at full speed as'above described. v

Thereafter, with two pumps on the line, the inflow rate to the suction reservoir will not be equal to the output rate of the two pumps at full speed and thus the fluid level will be drawn down. Again, the float and

weight

33 and 34 respectively, will be responsive to'this change in the fluid level to rotate sprocket wheel 31, shaft 29, and rephasing shaft 50 through its gear train as described above for the first pump, so as to vary the potentiometer resistance and the magnetic drives 21 of the two pumping units now in operation to adjust or lower the pump speeds so that the pumping rate equals the inflow rate to the suction reservoir. i

When the two pumps in operation attain full speed and there is a further increase in the inflow rate to the suction chamber to raise'the fluid level therein a prescribed amount above the capacity of the two pumps, a third pump will be started in operation in the same manner as already described for the first two pumps. Referring to Fig. 5, it will be noted that the slot 68 in the cam 67 for the third pump has a Wider slot than the slot in the cam for the second pump, and the slot 68 in the cam 67 for the fourth pump has a wider slot than that in cam 67 for the third pump, so as to permit each pump to be started at a progressively higher level which is greater than the full pumping capacity of the pumps in operation.

The fourth pump is placed in operation in the same manner as above described and the speed of the pumps on the line is adjusted by the potentiometer rheostats in the same manner as already described.

will be rotated in an opposite direction to that which results in placing a pump in operation. Arm 66 will also be moved in adirection opposite toits originalmovement and will reposition its arm pin in slot 68 of the fourth pump cam until it contacts the lower edge of the slot to actuate the pump cam 67 in an opposite direction from its original movement or rotation to open the mercury switch 70 in the pump electrical circuit and thus stop the fourth pump. Thereafter, the three pumps remaining in operation will have their speeds adjusted by the potentiometers as already described so as to operate at a speed at which the pumping rate equals the inflow rate to the suction reservoir 13. Thereafter, as the inflow rate further decreases the otentiometers will decrease the three pumps remaining in operation until they are running at a minimum speed when the inflow rate de clines to a point which requires a lesser number of pumps in operation, the pin of arm 66 in the last pump placed in operation the third pump in this case, returns to contact the lower edge of the third pump cam slot 68 to trip the corresponding mercury switch and stop that pumping unit. In this manner, each successive pump remaining in operation will be stopped in sequence until there remains only one pump on the line, or the station is shut down.

Thus in the operation of the present invention, a first pump is placed in operation and thereafter has its speed adjusted so that the pumping rate equals the inflow rate to the station. Upon attainment of the full speed capacity of the pump, a further increase in the inflow rate to the station, and corresponding rise in the station fluid level, starts a second pump in operation at full speed. Since the inflow rate at this time is not equal to the out- I put rate of the two pumps at full speed the fluid level in the station is decreased or drawn down. Thereafter, actuating means are provided to decrease the speed of the two pumps in operation simultaneously to equalize the inflow and outflow rate. Thereafter, the sane operation is repeated for placing subsequent pumps in operation.

When there is a recession or decrease of the inflow rate to the station the present invention provides a reverse sequence of action to cut out the pumps in operation, one by one, to maintain the pumping rate of the station equal to the inflow rate thereto. Actuating means first reduce the speed of all pumps in ope-ration to the minimum speed and cut out the last pump started in operation. This permits those pumps remaining in operation to increase their speed to their maximum output capacity so that a lesser number of pumps maintain an output equal to the station inflow rate. This sequence of operation follows until the station requires only one pump in operation or until the operation of the station is completely shut down.

Inasmuch as the capacity of a centrifugal pump for a given speed is determined by the pressure against which the pump delivers, a variation in this pressure will cause a corresponding variation in the pumps capacity. For example, when a pump delivers against a uniform level in a river, a rise in the river level will impose a greater pressure on the pump and hence decrease its capacity, while a fall in the river level will decrease the pressure on the pump and, correspondingly, the pumps capacity will increase. Therefore, we see that delivery against a uniform river level or discharge pressure then sets the range of speed variation that can be used in a pump to effect a range of capacity change from to 100 percent.

In accordance with the present invention, control means are provided for a pumping station to maintain the inflow rate to the pumping station equal to the outflow therefrom with variations in the delivery pressure of the station, caused by a change in the river level to which the station discharges. If we assume in the present invention that the change of the pump speed is from 70 to 100 percent to change the capacity of the pump from been-set in the. controlsfor the minimum pressure or river level, a rise in the river level will impose a greater pressure on the pump and the 10 percent pump capacity condition will require a greater rate of speed for the pump than the 70 percent normal speed. This requires a repositioning of the potentiometer for the pump with a greater excitation required in the magnetic drive 25 so that the inflow rate to the reservoirsuction =13 and the pumping rate out of the station will be equal, regardless of the variation in the pump delivery pressure caused by a change in the river level to-which the pump is discharging.

The liquid level in the mercury reservoir will vary in accordance with the vacuum pressure in fluid pressure line 84 and connecting pipe 85 in communication with the syphon 15 on the discharge side of the pump. A vacuum pressure is generated in the mercury reservoir and connecting lines thereto by closing the syphon breaker valve 88 in the syphon so that the discharge of water by the pump 11 generates the Vacuum. The opening of valve 86 in pipe 65 and valve 87 in line 34 permits communication of the mercury reservoir with the syphon of the respective pump.

When there is a rise in the river level this causes a decrease in the vacuum pressure so that the mercury level in the reservoir rises and float 82 moves upwardly -to rotate sprocket wheel 77 in one direction to rephase the potentiometer for a higher-speed to maintain the suction reservoir fluid level unchanged.

When the level of the river decreases there is a higher vacuum pressure in

lines

84 and 85 so that the mercury level in the mercury reservoir decreases and chain 89 and float 82 and weight =81 cause the sprocket wheel to be rotated in the opposite direction to rephase the potentiometer for a lower speed to maintain the suction reservoir level unchanged.

Sprocket wheel 77 is adapted to rotate in response to the liquid level change in the mercury filled reservoir 83 through chain carried by sprocket wheel 77 and having a float 82 in the reservoir and a weight 81 on the other end thereof.

The movement of arm '52 is effected by rotation of sprocket wheel 77 and gear 78 fixed on shaft 76 which meshes with gear 79 fixed toshaft 50 to which arm 52 is fixedr The rephasing or repositioning of the actuating means 27 to compensate for the variation in the delivery pressure due to the change in the river level is accomplished by moving crank arm 52 from its previously maintained position while shaft 29 and gear- 57 remain stationary. Rotating arm 52 about shaft 50 cause gears 54 and '55 to roll and mesh over gears 56 and '57, respectively. Shaft 50 will then rotate a constant amount as will the

gears

54 and 55. Since

gears

54 and 55 are of different sizes, gear 56 is rotated by differential action while gear I 57 remains stationary. Gear 57 remains stationary because the frictional torque of gears '54. and '55 is relatively small as compared to that of the buoyancy action of the float 34, sprocket wheel 3'1 and gear 57 ,meshing with gears 59 on shaft 29. Gear 56in turn, rotates gear 58 and pitman arm 60 connected thereto. The pitman arm in turn moves cam roller 61 onthe. outer end thereof in slot '62 disposed in cam 36.. The movement of the cam roller causes cam 36 to slide in slot 3'7 and thereby moves the rack 39 connected thereto. Rack 39 in turn moves the potentiometer rheostat 26 so that the pump pointers 43 fixed to shafts 4-1 and. 42 contact the potentiometer at varying positions to vary the resistance therein. Thus, the speed of the pump is then adjusted independently of any motion from shaft- '29. Referring to Figure 3, crank 52 and gear 54 may be in the position shown in Figure 3 before being rephased to compensate for a variance in the pump delivery pressure due to a change in the river level, and in the horizontal position after rephasing, as above described.

Thus, in the present invention, while a river: level corresponding to a high syphon vacuum and a low pumping pressure has the effect of a speed adjustment functioning from 70 to 100 percent of the pump speed, in a capacity from 10 percent to maximum, all caused by a suction reservoir level change from zero to 1 /2 feet, the higher river level rephases the control speed for 85 to 100 percent speed variation and for a lesser amount of well level variation, for example, from to 1 ft. change.

The indicated position of the pitman roller 61 in Figure 3 is at the minimum speed point, with the maximum speed point being at the upper endoi the slot. Further travel of the roller 61 in a vertically downward position does not allow any further movement of rack 39 since the track is circular. This portion of the track 62 is known as over-travel and allows the pump unit to opcrate at full speed and the suction reservoir level to rise steadily.

The mercury switches 70 for the second, third and fourth pumps are positioned with respect to their respective cams 67 so as to close the electrical circuit of each respective pump when the pitman roller 61 is in the over-travel position at successively greater amounts of over-travel. Thus, when not rephased by the delivery pressure control the suction reservoir levels at which the second, third and fourth pumps are placed in operation is 2 ft, with /2 ft. over-travel, 2% ft., with /1 ft. overtravel, 2 /2 ft, with 1 ft. over-travel, respectively. When rephased by the delivery pressure control the starting levels are not altered but the amount of over-travel is greater in the cam track 62.

Thus, the present invention provides a control system for a pumping station to maintain the inflow rate to the pumping station equal to the outflow therefrom with variations in the delivery pressure. of the station caused by a change in the river level to which the station discharges.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown but that they may be widely modified within the invention defined by the claims.

What is claimed is:

1. In a flow control and rephasing mechanism for pumping systems having a suction reservoir and a discharge outlet, a plurality of pumps having their suction inlets connected to said suction reservoir and their discharge outlets connected to the discharge outlet of the pumping system, a constant speed driving means for each of said pumps, and variable means connecting each of said driving means to its corresponding pump and adapted to vary the output flow capacity thereof, said flow control and rephasing mechanism operatively interconnected to said constant speed motor and said variable means and for regulating the output flow capacity of said pumping system, said flow control comprising a starting and stopping mechanism, an output adjusting mechanism and a control means responsive to the level in said suction reservoir and operatively connected to said output adjusting mechanism and said starting and stopping mechanism and adapted to start and stop the pumps and adjust the output flow therefrom in accordance with the rise and tall of the fluid level in the suction reservoir, said rephasing means including an output readjusting mechanism operatively interconnected to said output adjusting mechanism to adjust the output from said pumps in accordance with the flow conditions in the discharge outlet of said pumping system, a mechanical actuating means operatively connected to said output readjusting mechanism and sensing means in the discharge outlet of said pumping system and operatively connected to said mechanical actuating means to signal same to actuate the output readjusting mechanism to vary the output from said pumps.

2. The flow control and rephasing mechanism of claim reservoir for holding a fluid therein, a float and weight mechanism carried by a sprocket wheel, and said float adapted to be buoyed up by the fluid in the reservoir.

4. The flow control and rephasing mechanism of claim 3 wherein the sensing means comprises a vacuum conduit in communication with said reservoir and operatively connected to said discharge outlet to sense flow conditions therein.

5. The flow control and rephasing mechanism of claim 4 wherein each pump includes a siphon member interconnecting the discharge thereof to the discharge outlet and the vacuum conduit in communication with the reservoir is connected to the siphon to sense flow conditions therein.

6. The flow control and rephasing mechanism of claim 1 wherein each pump includes a siphon member interconnecting the discharge thereof to the discharge outlet and the sensing means is connected to said siphon member to sense flow conditions therein.

7. In a flow control and rephasing mechanism for pumping systems having a suction reservoir and a discharge outlet, a pumping means having its suction inlet connected to said suction reservoir and its discharge connected to the discharge outlet of said pumping system, driving means for the pump means, and variable means connecting said driving means to said pump means to vary the output flow capacity thereof, said flow control and rephasing mechanism operatively interconnected to said driving means and said variable means and for regulating the output flow capacity of said pumping system, said flow control comprising a cam, a starting and stopping mechanism, an output adjusting mechanism and a first control means responsive to the level in said suction reservoir and operatively connected to said output adjusting mechanism through said cam and said starting and stopping mechanism and adapted to adjust the output flow from said pump means in accordance with the rise and fall of the fluid level in the suction reservoir, said rephasing means comprising an output readjusting mechanism operatively connected to said output adjusting mechanism to adjust the output from said pumps in accordance with the flow conditions in the discharge outlet of said pumping system, a second control means including actuating means operatively connected to said output readjusting mechanism and sensing means in the discharge outlet of said pumping system and operatively connected to said actuating means to signal said output readjusting mechanism to vary the output from said pump means.

8. The flow control and rephasing mechanism of claim 7 wherein said first and second control means is provided wgh a float and weight mechanism carried by a sprocket w eel.

9. The flow control and rephasing mechanism of claim 7 wherein said actuating means comprises a reservoir for holding a fluid therein, a float and weight mechanism carriedby a sprocket wheel, and said float adapted to be buoyed up by the fluid in the reservoir.

10. The flow control and rephasing mechanism of claim 9 wherein the sensing means comprises a vacuum conduit in communication with said reservoir and operatively connected to said discharge outlet to sense flow conditions therein.

11. The flow control and rephasing mechanism of claim 7 wherein the pump means includes a siphon member interconnecting the discharge thereof to the discharge outlet and the sensing means is connected to said siphon member to sense flow conditions therein.

12. The flow control and rephasing mechanism of claim 11 wherein the pump means includes a siphon mem- References Cited in the file of this patent UNITED STATES PATENTS Pocock Nov. 1, 1892 Pogue Nov. 28, 1916 Merritt June 30, 1931 Hofer Dec. 10, 1940 10 Cowherd et al. Jan. 11, 1949 Hofer July 25, 1950 Foote Oct. 5, 1954 Towle et a1 Feb. 7, 1956 Dorer May 7, 1957 Crabtree Aug. 20, 1957 Buck June 2, 1959 FOREIGN PATENTS Great Britain J an. 23, 1930 Great Britain Nov. 24, 1930 France May 3, 1937