GB2144883A - Improvements in or relating to peristaltic pumps - Google Patents
Improvements in or relating to peristaltic pumps Download PDFInfo
- Publication number
- GB2144883A GB2144883A GB08321701A GB8321701A GB2144883A GB 2144883 A GB2144883 A GB 2144883A GB 08321701 A GB08321701 A GB 08321701A GB 8321701 A GB8321701 A GB 8321701A GB 2144883 A GB2144883 A GB 2144883A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pump
- reservoir
- weight
- control means
- peristaltic pump
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D7/00—Control of flow
- G05D7/06—Control of flow characterised by the use of electric means
- G05D7/0617—Control of flow characterised by the use of electric means specially adapted for fluid materials
- G05D7/0629—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means
- G05D7/0635—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means by action on throttling means
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Reciprocating Pumps (AREA)
Abstract
A pumping arrangement comprises a peristaltic pump; a reservoir (22) for containing liquid (24) to be supplied by the pump; means (26,28) for measuring the weight of the reservoir and contents and for generating signals representative of the measurements; and computer control means (14) for controlling the pump in response to the signals from the measuring means. For ease of use, the pump and control means (14) are preferably provided together in a single unit (10) with the control means conveniently being pre- programmed. The unit (10) thus conveniently comprises a peristaltic pump head (12) and motor/gear box assembly together with a microprocessor controller (14) with associated keyboard (16) and display (18) for user interface. A method of dispensing liquid is also disclosed. <IMAGE>
Description
SPECIFICATION
Improvements in or relating to peristaltic pumps
Field of invention
This invention relates to peristaltic pumps and concerns a pumping arrangement using a peristaltic pump and also a method of dispensing liquid using a peristaltic pump.
Background to the invention
Peristaltic pumps have various advantages and as a result are widely used eg in medical, chemical and biochemical fields. However, the accurate and controlled supply of liquids by peristaltic pumps has always been limited by two major factors:
1. The squeezing action of the pump rollers on the tubing can cause a distortion of the tubing, which leads to reducing flow rates with time.
2. Any variations in supply voltage can cause the pump speed to vary.
Developments aimed at overcoming such problems have, to-date, concentrated on improving pump roller design and motor performance, resulting in expensive pumps which still fail to meet the long term accuracy requirements of many applications, such as media feed in continuous culture fermentation.
It is accordingly an object of the present invention to provide a novel arrangement and method for providing an accurately controllable flow of liquid from a peristaltic pump.
The invention
According to one aspect of the present invention there is provided a pumping arrangement, comprising a peristaltic pump; a reservoir for containing liquid to be supplied by the pump; means for measuring the weight of the reservoir and contents and for generating signals representative of the measurements; and computer control means for controlling the pump in response to the signals from the measuring means.
The principle of operation of the arrangement is that by measuring the rate of loss of weight from the reservoir of liquid, the speed of the pump can be controlled to maintain a steady flow rate. The pump design can therefore be simple, using feedback control to maintain steady flow, rather than a complex pump design.
The reservoir conveniently stands on a weighing platform containing a load cell. Because weight differences are measured, absolute accuracy of measurement is not required of the load cell; however, the load cell should be able to measure small differences in weight with high resolution, particularly for low flow rate applications.
For ease of use, the pump and control means are preferably provided together in a single unit, with the control means conveniently being pre-programmed. The unit thus conveniently comprises a peristaltic pump head and motor/gear box assembly together with a microprocessor controller with associated keyboard and display for user interface.
Hence, in a preferred aspect the present invention provides a pumping arrangement comprising a reservoir for containing liquid to be supplied to a peristaltic pump; means for measuring the weight of the reservoir and contents and for generating signals representative of the measurements; and a peristaltic pump with integral preprogrammed computer control means for controlling the pump in response to signals from the measuring means.
In a further aspect the present invention also provides a method of dispensing liquid comprising pumping liquid from a reservoir using a peristaltic pump; monitoring the weight of the reservoir and contents; and controlling the speed of the pump in response to the weight measurement to maintain a desired flow rate.
The invention will be further described, by way of example, with reference to the accompanying drawing in which Fig. 1 is a schematic view of an arrangement in accordance with the present invention.
Detailed description of the drawing
The illustrated arrangement includes a unit 10 comprising a peristaltic pump including a pump head 1 2 and motor/gear box assembly, the unit also comprising a microprocessor controller 1 4 with associated keyboard 1 6 and display 1 8 for user interface. Provision may also be made for interface with an external computer (not shown).
The peristaltic pump includes a pump tube 20 leading from a reservoir 22 containing liquid 24 to be pumped. The reservoir 22 stands on a weighing platform 26 containing a load cell 28 capable of measuring very small weight differences with high resolution. The load cell 28 includes means for generating signals representative of the measured weight differences and for supplying the signals via line 30 to the controller 1 4. The signals are fed via a high performance amplifier to a sixteen-bit A/D converter and are used as feedback control to regulate pump speed to achieve a desired pumping rate.
The arrangement has the following characteristics:
Maximum weight of reservoir 30kg
Minimum measurable weight of platform 2009 Flow range 50 - 500g/hour Accuracy +/- 5% over 1hr
period
+ / - 2% over
1 Ohr period
Operating temperature range 15-25 C
Input/Output of System
Keyboard entry of
a) Mass flow 50-SOOg/hour b) Volumetric flow 50-500mis/hour c) Fluid density (if (b) is required) 0.5-2.0g/ml
d) Pump voltage (as a % of maximum) 0-100%
A three-digit, seven-segment display will show either entered, or actual parameters for any of
the above.
In addition warning lights will be provided for
-no reservoir (weight < 250g) -no flow (no weight change in 30mins)
-invalid data entry -increased weight -rapid variation of flow rate -pump at maximum speed weight > 30kg
Claims (10)
1. A pumping arrangement, comprising a peristaltic pump; a reservoir for containing liquid
to be supplied by the pump; means for measuring the weight of the reservoir and contents and
for generating signals representative of the measurements; and computer control means for
controlling the pump in response to the signals from the measuring means.
2. An arrangement according to claim 1, wherein the reservoir stands on a weighing platform containing a load cell.
3. An arrangement according to claim 2, wherein the load cell is able to measure small
differences in weight with high resolution.
4. An arrangement according to claim 1, 2 or 3, wherein the pump and control means are
provided together in a single unit.
5. An arrangement according to claim 4, wherein the control means are pre-programmed.
6. An arrangement according to claim 4 or 5, wherein the unit comprises a peristaltic pump
head and motor/gear box assembly together with a microprocessor controller with associated
keyboard and display for user interface.
7. A pumping arrangement comprising a reservoir for containing liquid to be supplied to a
peristaltic pump; means for measuring the weight of the reservoir and contents and for
generating signals representative of the measurements; and a peristaltic pump with integral pre
programmed computer control means for controlling the pump in response to signals from the
measuring means.
8. A method of dispensing liquid comprising pumping liquid from a reservoir using a
peristaltic pump; monitoring the weight of the reservoir and contents; and controlling the speed
of the pump in response to the weight measurement to maintain a desired flow rate.
9. A pumping arrangement substantially as herein described with reference to, and as
shown in, the accompanying drawings.
10. A method of dispensing liquid substantially as herein described with reference to the
accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08321701A GB2144883A (en) | 1983-08-11 | 1983-08-11 | Improvements in or relating to peristaltic pumps |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08321701A GB2144883A (en) | 1983-08-11 | 1983-08-11 | Improvements in or relating to peristaltic pumps |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8321701D0 GB8321701D0 (en) | 1983-09-14 |
| GB2144883A true GB2144883A (en) | 1985-03-13 |
Family
ID=10547187
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08321701A Withdrawn GB2144883A (en) | 1983-08-11 | 1983-08-11 | Improvements in or relating to peristaltic pumps |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2144883A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2054200A (en) * | 1979-07-12 | 1981-02-11 | Auto Syringe Inc | Improved flow control for an intravenous feeding system |
| EP0100682A1 (en) * | 1982-08-03 | 1984-02-15 | Peritronic Medical Industries Plc | Fluid flow control process and apparatus |
-
1983
- 1983-08-11 GB GB08321701A patent/GB2144883A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2054200A (en) * | 1979-07-12 | 1981-02-11 | Auto Syringe Inc | Improved flow control for an intravenous feeding system |
| EP0100682A1 (en) * | 1982-08-03 | 1984-02-15 | Peritronic Medical Industries Plc | Fluid flow control process and apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8321701D0 (en) | 1983-09-14 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |