EP0100682A1 — Fluid flow control process and apparatus

Claim 1

Independent Claim 176 words

A process for dispensing fluid from a fluid'container (3) under the control of a flow controller or pump (7), comprising selecting a required delivery rate and producing a signal identifying the selected delivery rate, monitoring the weight of the fluid container (3) and its contents and producing weight signals corresponding to the loss in weight as fluid is dispensed from the container, processing the weight signals with respect to time and producing data identifying the actual delivery rate of the fluid, comparing the selected delivery rate signal with the actual delivery rate data and producing control data for adjusting the flow controller or the speed of.the pump motor so that the actual delivery rate substantially conforms with the selected rate, characterised by the steps of initially processing the selected delivery rate signal and producing control data identifying the setting of the flow controller or the speed of the pump motor nominally corresponding to the selected delivery rate, and utilising said control data to adjust the flow controller or pump speed upon initiation of the dispensing operation.

Claim 2

Dependent Claim 176 words

A process for dispensing fluid from a fluid'container (3) under the control of a flow controller or pump (7), comprising selecting a required delivery rate and producing a signal identifying the selected delivery rate, monitoring the weight of the fluid container (3) and its contents and producing weight signals corresponding to the loss in weight as fluid is dispensed from the container, processing the weight signals with respect to time and producing data identifying the actual delivery rate of the fluid, comparing the selected delivery rate signal with the actual delivery rate data and producing control data for adjusting the flow controller or the speed of.the pump motor so that the actual delivery rate substantially conforms with the selected rate, characterised by the steps of initially processing the selected delivery rate signal and producing control data identifying the setting of the flow controller or the speed of the pump motor nominally corresponding to the selected delivery rate, and utilising said control data to adjust the flow controller or pump speed upon initiation of the dispensing operation.

Claim 3

Dependent Claim 67 words

A process according to claim 1, characterised by the step of providing a routine giving the relationship between selectable delivery rates and nominal settings of the flow controller or speeds of the pump motor, and accessing said routine in response to selection of a delivery rate to establish the control data identifying the initial setting of the flow controller or pump speed for the selected delivery rate.

Claim 4

Dependent Claim 57 words

A process according to claim 2, characterised by the step of deriving a factor pertaining to fluid delivery rate from delivery rate information produced during a preceding dispensing operation, and utilizing said factor to modify the control data established by accessing said routine to provide for more accurate initial setting of the flow controller or pump speed.

Claim 5

Dependent Claim 74 words

A process according to claim 1, 2 or .3 , characterised by the step of determining when sufficient weight data has been assimilated, subsequently to initiation of the dispensing operation for the control data produced by the comparing step satisfactorily to control the flow controller or pump speed, and thereafter utilising said latter control data to adjust the flow controller or pump speed to achieve substantial conformity between the actual and selected delivery rates.

Claim 6

Dependent Claim 216 words

Flow control apparatus for a fluid dispensing system in which fluid is dispensed from a fluid container (3) under the control of a flow controller or pump (7), including selection means (42) for selecting a required delivery rate and producing a signal identifying the selected delivery rate, a weight sensing device (2) for monitoring the weight of the fluid container (3) and its contents and producing weight signals corresponding to the loss in weight as fluid is dispensed from the container, regulating means (39) for adjusting the flow controller or the speed of the pump motor, and data processing means (30) for processing the weight signals with respect to time and producing data identifying the actual delivery rate, said processing means being arranged to compare the actual delivery rate data with the selected delivery rate signal and control said regulating means so as to maintain the actual delivery rate in substantial conformity with the selected rate, characterised in that said processing means (30) is adapted initially to process the selected delivery rate signal and produce control data identifying the setting of the flow controller or the speed of the pump motor nominally corresponding to the selected delivery rate, said processing means supplying said control data to the regulating means (39) upon commencement of a dispensing operation.

Claim 7

Dependent Claim 216 words

Flow control apparatus for a fluid dispensing system in which fluid is dispensed from a fluid container (3) under the control of a flow controller or pump (7), including selection means (42) for selecting a required delivery rate and producing a signal identifying the selected delivery rate, a weight sensing device (2) for monitoring the weight of the fluid container (3) and its contents and producing weight signals corresponding to the loss in weight as fluid is dispensed from the container, regulating means (39) for adjusting the flow controller or the speed of the pump motor, and data processing means (30) for processing the weight signals with respect to time and producing data identifying the actual delivery rate, said processing means being arranged to compare the actual delivery rate data with the selected delivery rate signal and control said regulating means so as to maintain the actual delivery rate in substantial conformity with the selected rate, characterised in that said processing means (30) is adapted initially to process the selected delivery rate signal and produce control data identifying the setting of the flow controller or the speed of the pump motor nominally corresponding to the selected delivery rate, said processing means supplying said control data to the regulating means (39) upon commencement of a dispensing operation.

Claim 8

Dependent Claim 72 words

Apparatus according to claim 5, characterised in that said data processing means has a program memory (31) storing data providing the relationship between selectable delivery rates and the nominal settings of the flow controller or speeds of the pump motor, said processing means (30) being responsive to selection of a delivery rate to access said program memory and produce control data for setting the regulating means upon initiation of the dispensing operation.

Claim 9

Dependent Claim 80 words

Apparatus according to claim 5 or 6, characterised in that the data processing means is arranged to fetch a weight signal from the weight sensing device in response to a predetermined increment of weight change and to compute the actual delivery rate data, and further characterised in that the data'processing means is adapted to compute the actual delivery rate data having regard to the total quantity of fluid delivered and the total-time elapsed since the initiation of the dispensing operation.

Claim 10

Dependent Claim 109 words

Apparatus according to claim 5, 6 or 7, characterised in that the selection means (42) includes a video display device (11) for displaying the selected delivery rate, said selection means being selectively operable also to display total actual delivery data stored in the data processing means and further characterised in that the selection means is operable to set the total quantity of fluid to be dispensed during a dispensing operation and produce a total quantity signal, and said data processing means is adapted to store said total quantity signal and actuate the regulating means to stop delivery when the actual quantity of fluid delivered corresponds to said selected quantity.

Claim 11

Dependent Claim 66 words

Apparatus according to any one of the preceding claims 5 to 8, characterised in that the pump is a peristaltic pump (7) driven by a stepping motor (46), and the regulating means (39) includes a counter adjustable in response to the control data supplied by said processing means to produce motor drive pulses at varying repetition rates, whereby to control the speed of the stepping motor.

Claim 12

Dependent Claim 74 words

Apparatus according to claim 9, including means (49,50) for supplying a train of operating pulses to said regulating means at a constant repetition rate, said regulating means including a downcounter arranged to be zeroised by said operating pulses, and said downcounter being successively settable to predetermined counts in response to the control data supplied by the processing means and producing a drive pulse each time it is zeroised by said train of operating pulses.

Fluid flow control process and apparatus

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