PULSE CAPTURE UNIT AND APPARATUS FOR CONTROLLING THE BLENDING OF TWO FLOWABLE SUBSTANCES

• US 3,777,935 A
• Filed: 01/10/1972
• Issued: 12/11/1973
• Est. Priority Date: 10/19/1971
• Status: Expired due to Term

• Current Assignee: William Arthur Storey
• Original Assignee: William Arthur Storey
• Inventors: Storey, William Arthur
• Primary Examiner(s): Reeves, Robert B.
• Assistant Examiner(s): Scherbel, David A.
• Application Number:
  US05/216,492
• Time in Patent Office: 701 Days
• Field of Search: 235/151.34,92FL 222/14,15,16,20,26,36,37,76
• US Class Current: 222/16
• CPC Class Codes: B67D 7/744 involving digital counting
• CPC Class Codes: G05D 11/132 by controlling the flow of the individual components G05D11/133 takes precedence
• CPC Class Codes: G06F 7/62 Performing operations exclusively by counting total number of pulses ; Multiplication, division or derived operations using combined denominational and incremental processing by counters, i.e. without column shift G06F7/68 takes precedence
• CPC Class Codes: H03K 5/15066 using bistable devices H03K5/15093 takes precedence
• CPC Class Codes: H03K 5/1515 non-overlapping

Abstract

A device is described which will accept trains of pulse signals on inputs thereof and will provide corresponding trains of pulse signals on corresponding outputs such that the number of pulse signals in the train at any of these outputs is equal to the number of pulse signals on the train at the corresponding input and such that there is never coincidence of pulse signals on these outputs regardless of whether or not there is coincidence of pulse signals on the inputs. In application of the device to a blending system two pipe lines for fluids to be blended have respective pulse transducers connected to respective inputs of such a device. The transducer for the minor component of the blend provides its pulses via said device to a counter which on reaching a predetermined count corresponding to the volume of the minor component in a standard quantity of the desired blend produces a signal to close a valve in the minor component flow line. The pulses at both outputs of said device are counted together by a further counter which on reaching a count corresponding to said standard quantity re-sets the first mentioned counter causing said valve in the minor component flow line to open again.

Claims

1. Apparatus for controlling the blending of two flowable substances, comprising separate dispensing means for each of said substances, a control means for at least one of said dispensing means operable selectively to cause said one dispensing means to dispense its respective substance and to arrest dispensing of its respective substance, a transducer associated with each of said dispensing means and arranged to produce a pulse each time a predetermined quantity of the respective substance is dispensed, a pulse capture unit having two inputs each connected to a respective one of said transducers for receiving pulses produced thereby and corresponding outputs at which pulses are produced corresponding to the pulses applied to the corresponding input, said pulses appearing at the respective outputs of said pulse capture unit being noncoincident first counting means for counting the pulses appearing on one of the corresponding outputs of said pulse capture unit and corresponding to the pulses produced by the transducer associated with said one dispensing means, second counting means for counting together the pulses appearing on both of said corresponding outputs of the pulse capture unit, said second counting means having associated therewith means arranged to operate the control means for said one dispensing means each time that a second predetermined number of pulses has been counted by said second counting means since the preceding operation of said control means and said first counting means Having associated therewith means arranged to operate said control means for said one dispensing means to cause tha latter to cease dispensing when a first predetermined number of pulses smaller than said second predetermined number has been counted thereby since the preceding operation of said control means by said means associated with said second counting means, the relative mean flow rates of said dispensing means during each period in which both dispensers are dispensing being such that the ratio of the mean flow through said one dispensing means to the mean total flow in said period is greater than the ratio of quantity of substance dispensed by said one dispensing means to the total quantity in the desired blend, and said first and second predetermined numbers being in the last mentioned ratio.

2. The apparatus of claim 1 wherein said pulse capture unit includes respective pulse output means associated with each said input and a respective one of said outputs, pulse sequence means for operating said pulse output means repeatedly at different times, each said pulse output means including means for detecting the occurrence of a pulse signal on its associated input and for storing said signal until operated by said pulse sequence means, each said pulse output means including means for delivering a signal to the associated output, if and only if a signal has occurred at its associated input since the preceding operation thereof by said pulse sequence means said pulse sequence means being arranged so that no two of said pulse output means are operable thereby at the same time, whereby the device will produce at each of said outputs thereof a train of pulses each corresponding to a respective pulse at the associated input of the device and pulses on respective said outputs are noncoincident

3. The apparatus of claim 2 wherein said pulse sequence means has a plurality of control outputs and is arranged to produce pulse signals at said control outputs in a repeating sequence, and each said pulse output means is arranged to be operated to deliver a pulse at the associated output of the device if a signal is stored in said means associated with said output, on the occurrence of a pulse on an associated one of said further outputs of said pulse sequence means.

4. The apparatus of claim 3 wherein said pulse sequence means comprises an oscillator, a counter for counting the periods of said oscillator and a decoder driven by said counter decoder having a plurality of outputs constituting said control outputs of the pulse sequence means, the decoder being arranged to apply pulse signals in a repeating sequence to said control outputs thereof as successive oscillator periods are counted by said counter.

5. The apparatus of claim 3 for use where the pulse length and pulse interval of the pulses to be applied to any one of said inputs is always greater than a predetermined period, wherein said pulse sequence means is so arranged that said sequence is repeated in a period no greater than said predetermined period, wherein there are at least three control outputs of said pulse sequence means and wherein each said pulse output means is constituted by a circuit unit including first gating means having one output and at least three inputs, means connecting one said input to one of said control outputs of said pulse sequence means, first and second bistable means each having an output, a set input, and a re-set input, means connecting the outputs of said first and second bistable means with respective further said inputs of said first gating means, means connecting the output of said first gating means to the respective output of the device, said first gating means being arranged to pass to said output a signal provided on the control output connected to the first gating means only if enabling signals are applied by both of said bistable means to said outputs thereof, means for detecting the coincidence of a signal applied to the associated input of the device with a signal on a Further one of said control outputs and for applying a signal to the set input of said first bistable means on detecting such coincidence thereby to set the latter in its state providing an enabling signal at its output, means for applying a signal to the re-set input of said second bistable means to throw the latter into its state providing an inhibiting signal at its output, on the occurrence of a signal at said output of said first gating means and means for detecting the coincidence of the occurrence of a signal on a yet further one of said control outputs with the absence of a signal on the associated input of the device, and for applying a signal to the re-set input of said first bistable means and to the set input of said second bistable means on detection of such a coincidence, said one control output, said further control output and said yet further control output being so selected for each said circuit unit that in said sequence a signal will appear at said yet further one of said control outputs after the appearance of a signal at said further control output, each said circuit unit having its said first gating means connected to a different one of said control outputs of said pulse sequence.

6. The apparatus of claim 5 wherein each said circuit unit comprises a first NAND gate, having an output and two inputs, means connecting one said input to said further control output (with respect to the circuit unit concerned) and means connecting its other said input to the associated input of the device, means connecting the set input of said first bistable means to the output of said first NAND gate, a second NAND gate and means connecting the reset input of said first bistable means and the set input of said second bistable means to the output of a said second NAND gate, said second NAND gate having two inputs, means connecting one of said inputs to said yet further control output (with respect to the circuit unit concerned), an invertor and means connecting the other of said second NAND gate via the invertor to the associated input of the device.

7. The apparatus of claim 1 wherein at least said first predetermined number is variable to vary the proportions of the blend.

8. The apparatus of claim 1 wherein each said dispensing means includes a flow line, and flow controlling means selectively operable to prevent flow of the respective substance therethrough, to restrict flow therethrough to a predetermined extent and to allow unrestricted flow therethrough, both of said dispensing means being arranged to dispense at substantially equal rates in equivalent states of said flow controlling means, and switching means operable alternatively to connect said first counting means to either of said outputs of said device and to vary the control of said flow controlling means by said first and second counter means in such a way that when, in operation of the apparatus said second counting means has counted said second predetermined number of pulses, the flow control means of whichever dispenser has its transducer arranged, by virtue of the state of said switching means, to supply its pulses via said device to said first counter means, is thereby placed in its state allowing unrestricted flow therethrough and thereafter remains in its latter state until at least a substantial proportion of said first predetermined number of pulses have been counted by said first counting means, while at the same time the other of said dispensing means is maintained in its state restricting flow therethrough.

9. The apparatus of claim 8 wherein said control means is arranged at least after cutting off the flow from the dispensing means associated with the transducer providing the pulses counted by said first counter to maintain the flow controlling means of the other dispenser in its state permitting full flow until said second predetermined number of pulses has been counted by said second counting means and thereafter to return the latter flow controlling means to itS state permitting only restricted flow.

10. The apparatus of claim 1 wherein said control means includes means arranged when a predetermined proportion of said first predetermined number of pulses has been counted by said first counting means to change the flow controlling means of the dispensing means associated with the transducer providing the pulses being counted by said first counting means to its state permitting only restricted flow and to change the latter flow controlling means to its state preventing flow once said first predetermined number of pulses has been counted by said first counting means.

11. The apparatus of claim 1 wherein said first counting means comprises a counter and has associated therewith means for providing an output signal of a second value when the count in said counter reaches or exceeds said first predetermined number, and otherwise providing an output signal of a first value, and wherein said one dispensing means includes first flow control means having an input arranged to receive the latter output signals, said first flow control means being arranged in the presence of a signal of said second value to prevent flow of the respective substance from said dispenser means and in the presence of a signal of said first value to allow such flow, said second counting means being arranged each time said second predetermined number of pulses has been counted thereby to pass a re-setting signal to said first counting means to re-set the latter to zero.

12. The apparatus of claim 11 wherein said means associated with said counter in said first counting means includes register means in which said first predetermined number can be set, and comparator means arranged to provide said output signal of said second value when the number in said counter equals or exceeds the number in said register and otherwise to provide a signal of said first value.

13. The apparatus of claim 12 wherein said register means includes means for selecting the dispensing means which passes the substance providing the minor portion of the desired blend as said one dispensing means which includes first flow control means having an input to receive the output signal from said comparator.

14. The apparatus of claim 11 wherein each said dispensing means has associated therewith respective flow controlling means having a first and a second input and means arranged in the presence of a signal of a first value on both of said inputs to allow unrestricted flow through said dispensing means, arranged in the presence of a signal of said first value on said first input and a signal of a second value on said second input to allow restricted flow through said dispensing means, and arranged in the presence of a signal of said second value on said first input to prevent flow through said dispensing means, said comparator means being arranged to provide said output signal of said second value on a first output line associated therewith when the count in said first counter means equals or exceeds said first predetermined value thereof, said comparator means further being arranged to provide an output signal of said second value on a second output line associated therewith when the count in said first counter means reaches or exceeds a predetermined proportion of said first predetermined number and otherwise to provide on said second output line a signal of said first value, switching means operable to selectively connect said second input of one of said flow controlling means to said second output line and at the same time to connect said second input of the flow controlling means not so connected to the output of invertor means connected to said second output line, further switching means operable to selectively connect one of the outputs of said pulse capture unit to said counter means and yet further switching means operable to selectively connect said first input of one of said flow controlling means with said first output line of said comparator means, said switching means beIng ganged so that if the first input of the flow controlling means, of one of said dispensing means is connected to said first output line, the first counter means is connected to count the pulses from the transducer of the latter dispensing means and said second input of the latter flow controlling means is connected to the output of said invertor means, whereas said second input of the other flow controlling means is connected to said second output line whereby as long as the count in said first counter is less than said predetermined proportion of said predetermined number, the dispensing means whose transducer is providing the pulses being counted by said first counting means has its flow controlling means set to allow full flow while the other dispensing means has its flow controlling means set to allow restricted flow, and whereby when said predetermined proportion has been reached the dispensing means whose transducer is providing the pulses being counted by said first counter means has its flow controlling means set to restrict flow, while the other flow controlling means is set to allow full flow, and when said first predetermined number is reached the dispensing means whose transducer is providing the pulses being counted by said first counter means has its flow controlling means set to prevent flow.

15. The apparatus of claim 1 wherein each output of said pulse capture unit is also connected to a respective calculating device adapted to function as a divider the divisor of which is selected to correspond to the price per unit quantity of the respective substance, the outputs of said calculating devices being added via an OR gate in a counter whereby the price of the total amount of the blended substances dispensed is counted.