Fluid delivery system with deficit flow compensation
First Claim
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1. A fluid delivery apparatus for delivering fluid to a fluid receiving system comprising:
- (a) at least one pump having a piston for reciprocation within a pump chamber, said pump having a fluid inlet and a fluid outlet;
(b) isolating means for periodically isolating the outlet of said pump from the remainder of the fluid system for a period of time thereby creating a deficit flow period;
(c) refill means for refilling said pump chamber during said deficit flow period;
(d) variable piston drive means for driving said piston at various velocities;
(e) control means connected to said drive means for controlling the speed of said drive means;
(f) said control means including means for driving said drive means at a first predetermined speed during a normal delivery period to deliver fluid to said system at a normal delivery rate;
(g) deficit flow determining means for determining the quantity of fluid which would have been delivered during said deficit flow period had said pump been delivering fluid to said system at said normal delivery rate;
(h) said control means further including compensation means for driving said drive means at a second predetermined speed during a compensation period for a time sufficient to compensate for the deficiency in flow during said deficit flow period.
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Accused Products
Abstract
Method and apparatus for compensating for the deficiency in fluid flow occurring during the refill and piston chamber pump-up cycle of a single piston fluid pump are disclosed. The period of time during which the outlet valve is closed and no fluid is being delivered to the system is determined and the pump is driven at a speed greater than the normal delivery speed for a period of time such that the quantity of excess fluid delivered approximates the quantity of fluid that would have been delivered during the refill and pump-up period had the pump been delivering fluid at its normal delivery rate.
92 Citations
61 Claims
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1. A fluid delivery apparatus for delivering fluid to a fluid receiving system comprising:
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(a) at least one pump having a piston for reciprocation within a pump chamber, said pump having a fluid inlet and a fluid outlet; (b) isolating means for periodically isolating the outlet of said pump from the remainder of the fluid system for a period of time thereby creating a deficit flow period; (c) refill means for refilling said pump chamber during said deficit flow period; (d) variable piston drive means for driving said piston at various velocities; (e) control means connected to said drive means for controlling the speed of said drive means; (f) said control means including means for driving said drive means at a first predetermined speed during a normal delivery period to deliver fluid to said system at a normal delivery rate; (g) deficit flow determining means for determining the quantity of fluid which would have been delivered during said deficit flow period had said pump been delivering fluid to said system at said normal delivery rate; (h) said control means further including compensation means for driving said drive means at a second predetermined speed during a compensation period for a time sufficient to compensate for the deficiency in flow during said deficit flow period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 58, 59, 60, 61)
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11. The method of operating pumping apparatus for delivering fluid to a system, said apparatus including a pump having at least one piston, said pump having (i) a delivery period during which the piston is driven at a first predetermined delivery rate to provide a normal delivery fluid flow rate to said system, (ii) a refill and piston chamber pump-up period during which the output of said pump is isolated from said system creating a deficit flow period during which no fluid is being delivered to said system, the improvement comprising the steps of;
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(a) computing the quantity of fluid that would have been delivered to said system during the deficit flow period had said pump been delivering fluid to said system at its normal delivery rate; (b) driving said pump at a speed such that fluid is delivered to said system at a higher rate than said normal delivery rate for a period of time sufficient to compensate for the quantity not delivered during said deficit flow period. - View Dependent Claims (12, 13)
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14. In a fluid delivery system having a single piston pump and inlet and outlet valves to allow fluid to be drawn into the pump piston chamber during a refill cycle and fluid to be delivered to the outlet of the system at a predetermined flow rate during a normal delivery period and a control means for controlling the pump piston speed, the method of compensating said fluid delivery system for the deficiency in fluid flow during the period when the outlet valve is closed and no fluid is being pumped to said system comprising the steps of:
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(a) determining a first time period approximating the time period when said outlet valve is closed and said fluid delivery system is not delivering fluid at its outlet; (b) driving said pump piston at a delivery rate greater than its predetermined normal delivery rate for a second time period such that the excess flow during said second time period approximates the flow deficiency during said first time period. - View Dependent Claims (15, 16, 17, 18)
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19. Fluid delivery apparatus for delivering fluid to a system comprising:
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(a) a pump having at least one piston for reciprocation within a pump chamber; (b) an inlet valve for admitting fluid to said chamber during the refill portion of the stroke of said piston; (c) an outlet valve for closing the outlet of said pump during the refill and chamber pump-up portion of the piston stroke, said outlet valve opening to allow discharge of fluid to the system during at least a portion of the pumping stroke; (d) variable piston drive means for driving said piston at various speeds; (e) control means connected to said drive means for controlling the speed of said drive means; (f) said control means including means for driving said drive means at a first predetermined speed during a normal delivery period to deliver to the system a predetermined quantity of fluid per unit of time during such period; (g) means for determining the approximate time period during which said outlet valve is closed and said pump is not delivering fluid to the system; (h) said control means further including means for driving said drive means at a second predetermined speed greater than said first predetermined speed for a period of time such that the excess fluid flow during said period approximately equals the fluid flow deficiency during the period when said outlet valve is closed. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26)
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27. In a fluid delivery system having a pump including at least a single piston for reciprocation within a pump chamber, inlet and outlet check valves, a variable speed pump piston drive means and a control means for controlling the speed of said drive means, said control means (i) driving said drive means at a first predetermined speed during a normal delivery time period for delivering fluid at a first predetermined rate, (ii) driving said drive means at a second predetermined speed during a second time period when the outlet check valve is closed and said pump is in the refill and pump piston chamber pump-up portions of its stroke, the improvement comprising:
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means for determining the length of said second time period; said control means including means for driving said drive means at a third predetermined speed greater than said first predetermined speed such that fluid is delivered at a rate larger than said first predetermined rate; and means for determining the length of a third time period during which said drive means is operating at said third predetermined speed such that an excess quantity of fluid is delivered during said third time period which approximates the quantity undelivered during said second time period. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34)
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35. The method of operating fluid delivery apparatus for delivering fluid to a fluid receiving system, said apparatus including a pump having at least one piston, said pump having (i) a normal delivery period during which said piston is driven at a first predetermined delivery speed to provide a normal delivery fluid flow rate to said system, (ii) a refill and piston chamber pump-up period during which the output of said pump is isolated from said system creating a deficit flow period during which no fluid is being delivered to said system, the improvement comprising the steps of:
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(a) determining the duration of a time period TDF during which the output of said pump is isolated from said system and no fluid is being delivered by said pump to said system; (b) solving the equation ##EQU4## where FD is the fluid flow rate out of said pump into said system during the normal delivery period and FEX is a fluid flow rate in excess of FD which will be delivered by the pump to said system during a period of excess flow; driving said pump for a period of time equal to TEX at a delivery flow rate of FD +FEX whereby the quantity of fluid delivered during said time period TEX in excess of the quantity normally delivered during the time period TEX is equal to the quantity of fluid that would have been delivered to said system during the deficit flow period had said pump been delivering fluid to said system at its normal delivery rate. - View Dependent Claims (36, 37)
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38. A fluid delivery apparatus for delivering fluid to a fluid receiving system comprising:
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(a) at least one pump having a piston for reciprocation within a pump chamber, said pump having a fluid inlet and a fluid outlet; (b) isolating means for periodically isolating the outlet of said pump from the remainder of the fluid system for a period of time TDF thereby creating a deficit flow period; (c) refill means for refilling said pump chamber during said deficit flow period; (d) variable piston drive means for driving said piston at various speeds; (e) control means connected to said drive means for controlling the speed of said drive means; (f) said control means including means for driving said drive means at a first predetermined speed during a normal delivery period to deliver fluid to said system at a normal delivery rate FD and at a second predetermined speed greater than said first predetermined speed to delivery fluid to said system at a delivery rate which exceeds the normal delivery rate by an excess delivery rate FEX ; (g) means for determining the length of the deficit flow time period TDF ; (h) means for solving the equation ##EQU5## (i) said control means further including means for driving said drive means at said second predetermined speed for approximately said time period TEX whereby the excess quantity of fluid delivered during said time period TEX approximately equals the quantity of fluid which would have been delivered during the time period TDF had said apparatus been delivering fluid during such period at said normal delivery rate. - View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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50. In a fluid delivery apparatus for delivering fluid to a fluid receiving system, said apparatus having at least one single piston pump, inlet and outlet valves to allow fluid to be drawn into the pump piston chamber during a refill cycle and to be delivered under pressure to the system at a predetermined flow rate during a delivery period and control means for controlling the pump piston speed, the method of compensating said fluid delivery apparatus for the quantity of fluid undelivered to said system during the period TDF when the outlet valve is closed, comprising the steps of:
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(a) sampling system pressure during the delivery period; (b) generating a signal approximating the time when the outlet valve closes and the deficit flow time period TDF begins; (c) sampling and storing pump piston chamber pressure at least two points during the piston delivery stroke when both the inlet and outlet valves are closed; (d) determining the slope of the piston chamber pressure pump-up waveform; (e) determining a time when the piston chamber pressure would approximate a percentage of said stored system pressure if the outlet valve remained closed and using said determined time as the end of the deficit flow time period TDF ; (f) determining the time period TDF ; (g) solving the equation ##EQU6## where FD is said predetermined fluid flow rate and FEX is a fluid flow rate in excess of said predetermined flow rate; (h) driving said pump at a speed sufficient to deliver fluid at a flow rate equal to FD +FEX for a time equal to TEX. - View Dependent Claims (51, 52)
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53. A fluid delivery apparatus for delivering fluid to a fluid receiving system comprising:
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(a) at least one pump having a piston for reciprocation within a pump chamber, said pump having a fluid inlet and a fluid outlet; (b) isolating means for periodically isolating the outlet of said pump from the remainder of the fluid system for a first time period thereby creating a deficit flow period; (c) refill means for refilling said pump chamber during said deficit flow period; (d) variable piston drive means for driving said piston at various velocities; (e) control means connected to said drive means for controlling the speed of said drive means; (f) said control means including means for driving said drive means at a first predetermined speed during a normal delivery period to deliver fluid to said system at a normal delivery rate; (g) said control means including means for driving said pump at a second predetermined speed greater than said first predetermined speed for a second time period such that the excess quantity of fluid delivered during said second time period approximates the quantity of fluid which would have been delivered during said first time period had said pump been delivering fluid at said normal delivery rate during said first time period.
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54. A fluid delivery apparatus for delivering fluid to a fluid receiving system comprising:
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(a) at least one pump having a piston for reciprocation within a pump chamber, said pump having a fluid inlet and a fluid outlet; (b) isolating means for periodically isolating the outlet of said pump from the remainder of the fluid system for a period of time TDF thereby creating a deficit flow period; (c) refill means for refilling said pump chamber during said deficit flow period; (d) variable piston drive means for driving said piston at various speeds; (e) control means connected to said drive means for controlling the speed of said drive means; (f) said control means including means for driving said drive means at a first predetermined speed during a normal delivery period to deliver fluid to said system at a normal delivery rate FD and at a second predetermined speed greater than said first predetermined speed to delivery fluid to said system at a delivery rate which exceeds the normal delivery rate by an excess delivery rate FEX ; (g) means for determining the length of the deficit flow time period TDF ; (h) means for solving the equation ##EQU7## for the quantity TEX (i) said control means further including means for driving said drive means at said second predetermined speed for approximately said time period TEX whereby the excess quantity of fluid delivered during said time period TEX approximately equals the quantity of fluid which would have been delivered during the time period TDF had said apparatus been delivering fluid during such period at said normal delivery rate.
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55. A fluid delivery system comprising:
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(a) a plurality of pumps each including at least one piston for reciprocation within a pumping chamber, an outlet valve for periodically isolating the outlet of said pump from the remainder of the fluid system for a time period TDF thereby creating a deficit flow period during which no fluid is delivered by said pump to the remainder of the fluid system; (b) variable piston drive means for driving each of said pistons at various speeds; (c) control means connected to said drive means for controlling the speed of said drive means; (d) refill means for refilling each of said pump-up chambers with fluid during the respective deficit flow period of each said pump; (e) means for determining the time period TDF for each of said pumps; (f) said control means including means for driving each of said drive means at a first predetermined speed during a normal delivery period to deliver fluid to said system at a normal delivery rate; (g) said control means further including compensating means for driving each of said drive means at a second predetermined speed greater than said first delivery speed for a second period of time such that the excess flow during said second period of time approximates the deficit flow during a time period TDF. - View Dependent Claims (56, 57)
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Specification