Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B9/00—Piston machines or pumps characterised by the driving or driven means to or from their working members
  • F04B9/02—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being mechanical
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B13/00—Pumps specially modified to deliver fixed or variable measured quantities
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B17/00—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
  • F04B17/03—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by electric motors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/0009—Special features
  • F04B43/0081—Special features systems, control, safety measures
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/12—Machines, pumps, or pumping installations having flexible working members having peristaltic action
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/12—Machines, pumps, or pumping installations having flexible working members having peristaltic action
  • F04B43/1253—Machines, pumps, or pumping installations having flexible working members having peristaltic action by using two or more rollers as squeezing elements, the rollers moving on an arc of a circle during squeezing
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
  • F04B49/06—Control using electricity
  • F04B49/065—Control using electricity and making use of computers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B2201/00—Pump parameters
  • F04B2201/12—Parameters of driving or driven means
  • F04B2201/1208—Angular position of the shaft
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B2203/00—Motor parameters
  • F04B2203/02—Motor parameters of rotating electric motors
  • F04B2203/0213—Pulses per unit of time (pulse motor)

Definitions

• the present invention relates generally to the field of fluid pumps and more specifically to the use of a multiple resolution stepping drive for a peristaltic or rotary pump .
• Peristaltic pumps have a unique advantage over other pumps in that they can be cleaned by merely removing the tubing and discarding it . New tubing is rapidly loaded making product changeover quite easy and contamination free . Also, the fluid shearing effect on tubing, known with other pumps , does not exist with peristaltic pumps . This protects products being pumped such as fluids containing fragile blood cells .
• a major problem with peristaltic pumps is precision and accuracy . This is true even when stated accuracy is said to be some fixed value , for example +/ - 0.5% . Over_ a period of a product run, the tubing and other accessories can change resulting in a loss of precision, because the precision is directly related to the tube diameter as well as the rotor speed .
• the present ition relates to a method and system for controlling a rotary pun ,mp can be coupled to a stepper motor, and the stepper motor can be controlled with micro- or nano-stepping accuracy using a processor controlled drive system.
• the processor controlled drive system moves the stepper motor according to a predetermined move profile ; this causes the rotary pump to dispense a precision amount of fluid .
• the rotary pump can be a peristaltic pump or any other type of pump .
• the rotary pump can be coupled to the stepper motor through a reduction gear with a reduction ratio of 2 : 1 , 7 : 1 or similar .
• the stepper motor can have an internal rotational encoder, or it be mechanically coupled to a rotational position encoder so that a measure of the rotation position can be fed back to the processor .
• the processor can cause the stepper motor to interpolate between pulse positions of the encoder .
• the present invention it is possible to achieve a stepping resolution of at least 125 , 000 steps per revolution . With a 2 : 1 reduction gear, it is possible to achieve as high as 250 , 000 steps per revolution .
• the present invention allows the stepper motor to operate at different resolutions during a dispense cycle . An example might be 1000 steps per revolution which is then switched to 10 , 000 steps per revolution (or much greater) depending upon the needs of the application . DESCRIPTION OF THE DRAWINGS
• Fig . 1 shows Lock diagram of a stepper motor pump drive system .
• Fig . 2 shows a flowchart for a dispense algorithm.
• Fig . 3 shows a block diagram of a stepper motor pump driver attached to a peristaltic pump .
• Fig . 4 is a table of stepping resolutions .
• the present invention relates to the use of a multiple resolution stepping motor to drive a peristaltic or rotary pump to dispense fluids .
• a conventional peristaltic fluid pump (or alternatively any rotary pump) benefits by using a multi - resolution stepping drive to increase precision and hence overall system dispensing accuracy .
• a stepper motor such as an "Oriental " motor or equivalent can achieve micro- or nano-stepping resolution if properly driven . This type of motor can then be directly attached to a peristaltic pump .
• the improved control and resolution of ' the stepper motor allows ' the peristaltic " pump to dispense fluids with an accuracy approaching that of a linear pump and allows possible tubing w ion .
• a pump drive system is his is the system described in United States Patent number 6 , 739 , 478 by Bach et al .
• This system uses a microprocessor coupled with a position feedback system to determine the position of the pump .
• the position feedback is optional since the accuracy of the micro- or nano-stepping motor can be such that direct rotational position feedback may not be necessary .
• U. S . Patent 6 , 739 , 478 is hereby incorporated by reference .
• a peristaltic pump system can select and use any of the 16 resolutions in this embodiment of on-the-fly to assist in enhancing precision .
• Fig . 4 shows a table of stepping resolutions that can be used .
• the motor stepping rate can start at 1000 steps per revolution, and then for example, switch to 10 , 000 steps per revolution to improve precision as a dispensing goal (final dispensed quantity) is approached .
• a gear head can be optionally used to further improve precision .
• a VICI M6 multiple piston pump head could be run with a 2 : 1 gear head on a 16 step setting to achieve 250 , 000 steps per revolution .
• the same system could also run at 1000 steps per revolution .
• This type of stepper drive with or without a gear head, allows greater drive range and capability that can be currently found on peristaltic pumps .
• Fig . 1 shows a block diagram of possible electronics that could be used to drive a peristaltic pump .
• a micro- or nano-step motor can be driven with suitable drive electronics known in the art under the control of a microprocessor .
• the microprocessor can be any processor of any bit width and can also be a microcontroller .
• An example processor is a 16 bit processor made by Intel called the 80196.
• the processor can optionally couple into a CAN bus , an RS-232 interface, and can contain RAM, ROM and disk storage .
• Optional rotational position feedback can be used through an A/D converter if desired .
• Fig . 2 shows a flowchart that can be used for a sample dispense .
• a peristaltic (or any other) pump can be moved by creating a move profile .
• a Gaussian move profile is used.
• a step table is created that relates to accelerations , and the motor is moved according to the table .
• Fig . 3 shows a block diagram of a stepper motor with processor controlled driver coupled through an optional reduction gear to a peristaltic pump .
• Typical drive electronics are sold under the trade name of ONE PUMP by Scientific Products and Systems of Baltimore MD .
• This electronics can be used to drive both linear and rotary pumps .
• This electronics also ⁇ includes features " such ' as the " ability to " separately control a nozzle, linking of multiple pumps on a CAN bus , and control of pumps by programmable logic controllers (PLCs) .
• PLCs programmable logic controllers
• a Renishaw rotary 4096 »n encoder can be optionally interfaced to the controller to provide around 0.08 degree resolution (also some motors have internal revolution encoders) . Stepping motor steps can be used to interpolate between encoder signals allowing for finer resolution (settings above 6 in Fig . 4) .
• a home signal can be optionally incorporated so that counters can be calibrated and peristaltic pump rollers synchronized .

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Reciprocating Pumps (AREA)
• Control Of Stepping Motors (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=36678127

Family Applications (1)

Country Status (4)

Families Citing this family (9)

Family Cites Families (9)

• 2005
  • 2005-01-14 US US11/036,782 patent/US20050180856A1/en not_active Abandoned
• 2006
  • 2006-01-11 CA CA002594750A patent/CA2594750A1/en not_active Abandoned
  • 2006-01-11 WO PCT/US2006/000785 patent/WO2006076339A2/en not_active Ceased
  • 2006-01-11 EP EP06733662A patent/EP1838964A2/de not_active Withdrawn

Non-Patent Citations (1)

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