Fluid dispensing algorithm for a variable speed pump driven metering system

• US 6,913,933 B2
• Filed: 12/03/2001
• Issued: 07/05/2005
• Est. Priority Date: 12/03/2001
• Status: Expired due to Term

• Current Assignee: Ortho-Clinical Diagnostics Incorporated (The Carlyle Group LP (Corporate Private Equity))
• Original Assignee: Ortho-Clinical Diagnostics Incorporated (The Carlyle Group LP (Corporate Private Equity))
• Inventors: Parobek, Christopher M., Hyde, David D., Jacobs, Merrit N.
• Primary Examiner(s): Warden, Jill
• Assistant Examiner(s): Gordon, Brian R.
• Application Number:
  US10/005,257
• Publication Number:
  US 20030104634A1
• Time in Patent Office: 1,310 Days
• Field of Search: 422/100, 422/50, 422/62, 422/67, 422/63, 422/68.1, 436/180, 436/43, 436/54, 738/633.2, 738/64, 738/640.1, 738/641.1, 738/641.2, 738/641.3
• US Class Current: 436/180
• CPC Class Codes: B01L 2200/0615 Loss of fluid by dripping
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 3/0289 Apparatus for withdrawing or distributing predetermined quantities of fluid B01L3/02 takes precedence; sample taking G01N1/00; sample taking within automatic analysers G01N35/00; volume measuring in general G01F
• CPC Class Codes: F04B 13/00 Pumps specially modified to deliver fixed or variable measured quantities
• CPC Class Codes: F04B 7/06 the pistons and cylinders being relatively reciprocated and rotated
• CPC Class Codes: G01N 2035/102 Preventing or detecting loss of fluid by dripping
• CPC Class Codes: G01N 35/1016 Control of the volume dispensed or introduced
• CPC Class Codes: G05D 7/0676 by action on flow sources G05D7/0688, G05D7/0694 take precedence
• CPC Class Codes: Y10T 436/11 Automated chemical analysis
• CPC Class Codes: Y10T 436/119163 with aspirator of claimed structure
• CPC Class Codes: Y10T 436/2575 Volumetric liquid transfer

Abstract

A method for improving the fluid dispense rate in a metering system utilizing speed includes the steps of modifying the fluid flow rate profile during a portion thereof so as substantially increase or decrease the speed of the motor during certain portions of a metering cycle in order to improve the efficiency of the metering system. For a variable speed pump producing a sinusoidal speed profile, the pump motor speed can be increased to increase the dispense velocity during the beginning and end of the dispense phase to reduce perfusion and improve metered volume precision or a motor speed profile can be applied which is inverted relative to that of the variable speed pump to produce a constant velocity flow. Alternately or in addition to the above, the home position of the variable speed pump can be shifted to produce fluid velocity during the entirety of a dispense portion of a metering system cycle.

Claims

1. A method for improving the dispensability of a metering system, said metering system including at least one dispense nozzle, a fluid supply, and at least one variable speed pump fluidly interconnecting said at least one dispense nozzle and said fluid supply, said at least one variable speed pump including a pump motor and having a mechanism which produces a variable fluid flow rate profile for a constant motor speed, said method including the steps of:

aspirating fluid from said fluid supply;

dispensing aspirated fluid through said at least one dispense nozzle; and

effecting the relative velocity of the dispensed fluid by modifying a variable fluid rate flow using said pump motor during said dispensing step wherein said modifying step results in at least one of a change and a modification to said variable fluid flow rate profile and in which said relative velocity effecting step includes the step of offsetting a reference position of said pump motor in order to shift at least a portion of said variable fluid flow rate profile.

2. A method according to claim 1, wherein said variable speed pump produces a decrease in pump piston velocity at the end of said dispensing step, in which said offsetting step offsets said reference position to cause an increase in fluid dispense velocity at the end of said dispensing step.

3. A method according to claim 1, wherein said variable speed pump produces a sinusoidal fluid flow rate profile wherein the fluid flow rate becomes zero at the end of said dispensing step, wherein said offsetting step is applied to offset the end of said profile to provide a fluid flow rate at the end of said dispensing step.

4. A method according to claim 3, wherein a predetermined volume of fluid is dispensed onto a target, said method including the additional step of pre-dispensing residual fluid remaining from said dispensing step onto one of said target and a separate target prior to a subsequent aspirating and dispensing step.

5. A method according to claim 4, including the step of increasing the speed of said motor during at least said pre-dispensing step in order to increase the dispense velocity of said fluid.

6. A method for improving the dispensability of a metering system, said metering system including at least one dispense nozzle, a fluid supply, and at least one variable speed pump fluidly interconnecting said at least one dispense nozzle and said fluid supply, said at least one variable speed pump including a pump motor and having a mechanism which produces a variable fluid flow rate profile for a constant motor speed, said method including the steps of:

aspirating fluid from said fluid supply;

dispensing aspirated fluid through said at least one dispense nozzle; and

effecting the relative velocity of the dispensed fluid modifying a variable fluid rate flow using said pump motor during said dispensing step wherein said modifying step results in at least one of a change and a modification to said variable fluid flow rate profile, wherein said relative velocity effecting step includes the step of applying a variation in motor speed according to a profile having a shape which is inverted relative to said variable fluid flow rate profile.

7. A method for improving the dispensability of a metering system, said metering system including at least one dispense nozzle, a fluid supply, and at least one variable speed pump fluidly interconnecting said at least one dispense nozzle and said fluid supply, said at least one variable speed pump including a pump motor and having a mechanism which produces a variable fluid flow rate profile for a constant motor speed, said method including the steps of:

aspirating fluid from said fluid supply;

dispensing aspirated fluid through said at least one dispense nozzle; and

effecting the relative velocity of the dispensed fluid by modifying a variable fluid rate flow using said pump motor during said dispensing step wherein said modifying step results in at least one of a change and a modification to said variable fluid flow rate profile wherein said variable speed pump produces a sinusoidal fluid flow rate profile in which the beginning and end of said dispensing steps produce a fluid flow rate of zero from the dispense nozzle, said relative velocity effecting step including the step of increasing the speed of the pump motor along portions of said profile in order to increase the fluid flow rate.

8. A method for improving the dispensability of a metering system, said metering system including at least one dispense nozzle, a fluid supply, and at least one variable speed pump fluidly interconnecting said at least one dispense nozzle and said fluid supply, said at least one variable speed pump including a pump motor and having a mechanism which produces a variable fluid flow rate profile for a constant motor speed, said method including the steps of:

aspirating fluid from said fluid supply;

dispensing aspirated fluid through said at least one dispense nozzle; and

effecting the relative velocity dispensed fluid by modifying a variable fluid rate flow using said pump motor during said dispensing step wherein said modifying step results in at least one of a change and a modification to said variable fluid flow rate profile wherein said variable speed pump produces a sinusoidal fluid flow rate profile, said relative velocity effecting step including the step of applying a variation in motor speed to said pump over said dispensing step which includes a shape which is essentially inverted relative to said fluid flow rate profile to produce a substantially constant dispense velocity during dispensing step.

9. A method for improving the dispensability of a metering system, said metering system including at least one dispense nozzle, a fluid supply, and at least one variable speed pump fluidly interconnecting said at least one dispense nozzle and said fluid supply, said at least one variable speed pump including a pump motor and having a mechanism which produces a variable fluid flow rate profile for a constant motor speed, said method including the steps of:

aspirating fluid from said fluid supply;

dispensing aspirated fluid through said at least one dispense nozzle; and

effecting the relative velocity dispensed fluid by modifying a variable fluid rate flow using said pump motor during said dispensing step wherein said modifying step results in at least one of a change and a modification to said variable fluid flow rate profile, wherein said variable speed pump produces a fluid flow rate profile in which the fluid flow rate during the dispensing step is variable and characterized by an initially low fluid flow rate relative to the remaining portions of said profile, said relative velocity effecting step including the step of increasing the speed of said pump motor during at least the beginning of said dispensing step so as to increase the fluid flow rate sufficiently to prevent perfusion of dispensed fluid.

10. A method for improving the dispensability of a metering system used in a clinical analyzer, said metering system including at least one metering tip, a fluid supply, and at least one pump fluidly interconnecting said at least one metering tip and said fluid supply, said pump including a pump motor and having a mechanism which produces a variable fluid flow rate profile for a constant motor speed, said method including the steps of:

a. aspirating fluid from said fluid supply using a metering tip attached to a proboscis;

b. dispensing aspirated fluid through said metering tip into a reaction vessel; and

c. effecting the relative velocity fluid dispensed by said metering system by modifying a variable fluid rate flow using said pump motor during said dispensing step wherein said modifying step results in at least one change and modification to said variable fluid flow rate profile, wherein said relative velocity effecting step includes the step of offsetting a reference position of said pump motor in order to shift at least a portion of said fluid flow rate profile.

11. A method according to claim 10, wherein said variable speed pump produces a decrease in pump piston velocity at the end of said dispensing step, in which said offsetting step offsets said reference position to cause an increase in fluid dispense velocity at the end of said dispensing step.

12. A method according to claim 10, wherein said variable speed pump produces a sinusoidal fluid flow rate profile wherein the fluid flow rate becomes zero at the end of said dispensing step, wherein said offsetting step is applied to offset the end of said profile to provide a non-zero fluid flow rate at the end of said dispensing step.

13. A method according to claim 12, wherein a predetermined volume of fluid is dispensed into a first reaction vessel, said method including the additional step of pre-dispensing residual fluid remaining from said dispensing step onto one of said first reaction vessel and a second reaction vessel prior to a subsequent aspirating and dispensing step therein.

14. A method according to claim 13, including the step of increasing the speed of said motor during at least said pre-dispensing step in order to increase the dispense velocity of said fluid.

15. A method for improving the dispensability of a metering system used in a clinical analyzer, said metering system including at least one metering tip, a fluid supply, and at least one pump fluidly interconnecting said at least one metering tip and said fluid supply, said pump including a pump motor and having a mechanism which produces a variable fluid flow rate profile for a constant motor speed, said method including the steps of:

a. aspirating fluid from said fluid supply using a metering tip attached to a proboscis;

b. dispensing aspirated fluid through said metering tip into a reaction vessel; and

c. effecting the relative velocity fluid dispensed by said metering system by modifying a variable fluid rate flow using said pump motor during said dispensing step wherein said modifying step results in at one change and modification to said variable fluid flow rate profile, wherein said relative velocity effecting step includes the step of applying a variation in motor speed according to a profile having a shape which Is inverted relative to said fluid flow rate profile.

16. A method for improving the dispensability of a metering system used in a clinical analyzer, said metering system including at least one metering tip, a fluid supply, and at least one pump fluidly interconnecting said at least one metering tip and said fluid supply, said pump including a pump motor and having a mechanism which produces a variable fluid flow rate profile for a constant motor speed, said method including the steps of:

a) aspirating fluid from said fluid supply using a metering tip attached to a proboscis;

b) dispensing aspirated fluid through said metering tip into a reaction vessel; and

c) effecting the relative velocity fluid dispensed by said metering system by modifying a variable fluid rate flow using said pump motor during said dispensing step wherein said modifying step results in at least one change and modification to said variable fluid flow rate profile, wherein said variable speed pump produces a sinusoidal fluid flow rate profile in which the beginning and end of said dispensing steps produces a fluid flow rate of zero from the metering tip, said relative velocity effecting step including the step of increasing the speed of the pump motor along portions of said profile in order to increase the fluid flow rate.

17. A method for improving the dispensability of a metering system used in a clinical analyzer, said metering system including at least one metering tip, a fluid supply, and at least one pump fluidly interconnecting said at least one metering tip and said fluid supply, said pump including a pump motor and having a mechanism which produces a variable fluid flow rate profile for a constant motor speed, said method including the steps of:

a) aspirating fluid from said fluid supply using a metering tip attached to a proboscis;

b) dispensing aspirated fluid through said metering tip into a reaction vessel; and

c) effecting the relative velocity fluid dispensed by said metering system by modifying a variable fluid rate flow using said pump motor during said dispensing step wherein said modifying step results in at least one change and modification to said variable fluid flow rate profile, wherein said variable speed pump produces a sinusoidal fluid flow rate profile, said relative velocity effecting step including the step of applying a variation in motor speed to said pump over said dispensing step which includes a shape which is essentially inverted relative to said fluid flow rate profile to produce a substantially constant dispense velocity during dispensing step from said metering tip.

18. A method for improving the dispensability of a metering system used in a clinical analyzer, said metering system including at least one metering tip, a fluid supply, and at least one pump fluidly interconnecting said at least one metering tip and said fluid supply, said pump including a pump motor and having a mechanism which produces a variable fluid flow rate profile for a constant motor speed, said method including the steps of:

a) aspirating fluid from said fluid supply using a metering tip attached to a proboscis;

b) dispensing aspirated fluid through said metering tip into a reaction vessel; and

c) effecting the relative velocity of fluid dispensed by said metering system by modifying a variable fluid rate flow using said pump motor during said dispensing step wherein said modifying step results in at least one change and modification to said variable fluid flow rate profile, wherein said variable speed pump produces a fluid flow rate profile in which the fluid flow rate during the dispensing step is variable and characterized by an initially low fluid flow rate relative to the remaining portions of said profile, said relative velocity effecting step including the step of increasing the speed of said pump motor during at least the beginning of said dispensing step so as to increase the fluid flow rate sufficiently to prevent perfusion of dispensed fluid relative to said metering tip.

19. A metering system comprising:

a) at least one dispense nozzle;

b) a fluid supply, and

c) at least one variable speed pump fluidly interconnecting said at least one dispense nozzle and said fluid supply, said at least one variable speed pump including a motor and mechanical means for producing a variable fluid flow rate profile for a constant motor speed during at least one phase of a metering cycle including a dispensing phase, said system further including means for effecting the relative velocity of dispensed liquid through said at least one dispense nozzle using said pump motor by modifying a fluid flow rate using said motor during at least one phase of said metering cycle and resulting in at least one of a change and modification to the variable fluid flow rate profile A, wherein said relative velocity effecting means includes means for offsetting a reference position of said pump motor in order to shift at least a portion of said fluid flow rate profile.

20. A metering system according to claim 19, wherein said variable speed pump produces a decrease in pump piston velocity at the end of said dispensing step, wherein said reference position can be offset sufficiently to cause a relative increase in fluid dispense velocity at the end of a dispense phase.

21. A metering system according to claim 19, wherein said variable speed pump produces a sinusoidal fluid flow rate profile in which the fluid flow rate becomes zero at the end of a dispense phase, wherein said offsetting means is applied to offset the end of said profile to provide a non-zero fluid flow rate at the end of said dispense phase.

22. A metering system according to claim 21, wherein a predetermined volume of fluid is dispensed into a first target during the dispense phase and in which offsetting causes a residual volume of fluid remaining to complete the dispense phase of the cycle following a dispense phase requiring a pre-dispense phase in which the residual fluid volume is dispensed into one of the first and a separate second target prior to an aspiration phase.

23. A metering system according to claim 22, wherein said relative velocity effecting means includes means for increasing the speed of the pump motor during at least said pre-dispense phase in order to increase the dispense velocity of said fluid.

24. A metering system according to claim 19, wherein said system is used in a clinical analyzer.

25. A metering system comprising:

a) at least one dispense nozzle;

b) a fluid supply, and

c) at least one variable speed pump fluidly interconnecting said at least one dispense nozzle and said fluid supply, said at least one variable speed pump including a motor and mechanical means for producing a variable fluid flow rate profile for a constant motor speed during at least one phase of a metering cycle including a dispensing phase, said system further including means for effecting the relative velocity of dispensed liquid through said at least one dispense nozzle using said pump motor by modifying a fluid flow rate using said motor during at least one phase of said metering cycle and resulting in at least one of a change and modification to the variable fluid flow rate profile, wherein said relative velocity effecting means includes means for applying a variation in motor speed according to a profile having a shape which is substantially inverted relative to said fluid flow rate profile.

26. A metering system comprising:

a) at least one dispense nozzle;

b) a fluid supply, and

c) at least one variable speed pump fluidly interconnecting said at least one dispense nozzle and said fluid supply, said at least one variable speed pump including a motor and mechanical means for producing a variable fluid flow rate profile for a constant motor speed during at least one phase of a metering cycle including a dispensing phase, said system further including means for effecting the relative velocity of dispensed liquid through said at least one dispense nozzle using said pump motor by modifying a fluid flow rate using said motor during at least one phase of said metering cycle and resulting in at least one of a change and modification to the variable fluid flow rate profile, wherein said variable speed pump produces a sinusoidal fluid flow rate profile in which the beginning and end of said dispensing steps produces a fluid flow rate of zero from the metering tip, said relative velocity effecting means including means for increasing the speed of the pump motor along portions of said flow rate profile in order to increase the fluid flow rate.

27. A metering system comprising:

a) at least one dispense nozzle;

b) a fluid supply, and

c) at least one variable speed pump fluidly interconnecting said at least one dispense nozzle and said fluid supply, said at least one variable speed pump including a motor and mechanical means for producing a variable fluid flow rate profile for a constant motor speed during at least one phase of a metering cycle including a dispensing phase, said system further including means for effecting the relative velocity of dispensed liquid through said at least one dispense nozzle using said pump motor by modifying a fluid flow rate using said motor during at least one phase of said metering cycle and resulting in at least one of a change and modification to the variable fluid flow rate profile, wherein said variable speed pump produces a sinusoidal fluid flow rate profile, said relative velocity effecting means including means for applying a variation in motor speed to said pump during said dispense phase according to a motor speed profile having a shape which is essentially inverted relative to said fluid flow rate profile to produce a substantially constant dispense velocity during dispensing step.

28. A metering system comprising:

a) at least one dispense nozzle;

b) a fluid supply, and

c) at least one variable speed pump fluidly interconnecting said at least one dispense nozzle and said fluid supply, said at least one variable speed pump including a motor and mechanical means for producing a variable fluid flow rate profile for a constant motor speed during at least one phase of a metering cycle including a dispensing phase, said system further including means for effecting the relative velocity of dispensed liquid through said at least one dispense nozzle using said pump motor modifying a fluid flow rate using said motor during at least one phase of said metering cycle and resulting in at least one of a change and modification to the variable fluid flow rate profile, wherein said variable speed pump produces a fluid flow rate profile in which the fluid flow rate during the dispensing phase is variable and characterized by an initially low fluid flow rate relative to the remaining portions of said profile, said relative velocity effecting means including means for increasing the speed of said pump motor during at least the beginning of said dispensing step so as to increase the fluid flow rate sufficiently to prevent perfusion of dispensed fluid relative to said dispense nozzle.

29. A clinical analyzer comprising:

a housing;

a metering system disposed within said housing for aspirating and dispensing at least one fluid into at least one reaction vessel for purposes of obtaining a reaction; and

a processing system for detecting at least one predetermined aspect of the reaction, said metering system including;

i) a proboscis retaining at least one of a plurality of metering tips;

ii) a fluid supply, and

iii) at least one pump fluidly interconnecting said at least one proboscis and retained metering tip and said fluid supply, said pump including a motor and mechanical means for producing a variable fluid flow rate profile for a constant motor speed during at least one phase of a metering cycle including a dispensing phase,

said analyzer further including means for effecting the relative velocity of fluid dispensed from said metering tip to modify a fluid flow rate of said pump during at least one phase of said metering cycle and thereby at least one of changing and modifying the variable fluid flow rate profile, wherein said relative velocity effecting means includes means for offsetting a reference position of said pump motor in order to shift at least a portion of said fluid flow rate profile.

30.A clinical analyzer according to claim 29, wherein said variable speed pump produces a decrease in pump piston velocity at the end of said dispensing step, wherein said reference position can be offset sufficiently to cause a relative increase in fluid dispense velocity at the end of a dispense phase.

30. A clinical analyzer according to claim 29, wherein said variable speed pump produces a sinusoidal fluid flow rate profile in which the fluid flow rate becomes zero at the end of a dispense phase, wherein said offsetting means is applied to offset the end of said profile to provide a non-zero fluid flow rate at the end of said dispense phase.

31. A clinical analyzer according to claim 31, wherein a predetermined volume of fluid is dispensed from said metering tip into a first reaction vessel during the dispense phase and in which offsetting causes a residual volume of fluid remaining to complete the dispense phase of the cycle following a dispense phase requiring a pre-dispense phase in which the residual fluid volume is dispensed into one of the first and a separate second reaction vessel housed in said analyzer prior to an aspiration phase.

32. A clinical analyzer according to claim 32, wherein said relative velocity effecting means includes means for increasing the speed of the pump motor during at least said pre-dispense phase in order to increase the dispense velocity of said fluid.

33. A clinical analyzer comprising:

a housing;

a metering system disposed within said housing for aspirating and dispensing at least one fluid into at least one reaction vessel for purposes of obtaining a reaction; and

a processing system for detecting at least one predetermined aspect of the reaction, said metering system including;

i) a proboscis retaining at least one of a plurality of metering tips;

ii) a fluid supply, and

iii) at least one pump fluidly interconnecting said at least one proboscis and retained metering tip and said fluid supply, said pump including a motor and mechanical means for producing a variable fluid flow rate profile for a constant motor speed during at least one phase of a metering cycle including a dispensing phase,

said analyzer further including means for effecting the relative velocity of fluid dispensed from said metering tip to modify a fluid flow rate of said pump during at least one phase of said metering cycle and thereby at least one of changing and modifying the variable fluid flow rate profile, wherein said relative velocity effecting means includes means for applying a variation in motor speed according to a profile having a shape which is substantially inverted relative to said fluid flow rate profile.

34. A clinical analyzer comprising:

a housing;

a metering system disposed within said housing for aspirating and dispensing at least one fluid into at least one reaction vessel for purposes of obtaining a reaction; and

a processing system for detecting at least one predetermined aspect of the reaction, said metering system including;

i) a proboscis retaining at least one of a plurality of metering tips;

ii) a fluid supply, and

iii) at least one pump fluidly interconnecting said at least one proboscis and retained metering tip and said fluid supply, said pump including a motor and mechanical means for producing a variable fluid flow rate profile for a constant motor speed during at least one phase of a metering cycle including a dispensing phase,

said analyzer further including means for effecting the relative velocity of fluid dispensed from said metering tip to modify a fluid flow rate of said pump during at least one phase of said metering cycle and thereby at least one of changing and modifying the variable fluid flow rate profile, wherein said variable speed pump produces a sinusoidal fluid flow rate profile in which the beginning and end of said dispensing steps produces a fluid flow rate of zero from the metering tip, said relative velocity effecting means including means for increasing the speed of the pump motor along portions of said flow rate profile in order to increase the fluid flow rate.

35. A clinical analyzer comprising:

a housing;

a metering system disposed within said housing for aspirating and dispensing at least one fluid into at least one reaction vessel for purposes of obtaining a reaction; and

a processing system for detecting at least one predetermined aspect of the reaction, said metering system including;

i) a proboscis retaining at feast one of a plurality of metering tips;

ii) a fluid supply, and

iii) at least one pump fluidly interconnecting said at least one proboscis and retained metering tip and said fluid supply, said pump including a motor and mechanical means for producing a variable fluid flow rate profile for a constant motor speed during at least one phase of a metering cycle including a dispensing phase,

said analyzer further including means for effecting the relative velocity of fluid dispensed from said metering tip to modify a fluid flow rate of said pump during at least one phase of said metering cycle and thereby at least one of changing and modifying the variable fluid flow rate profile, wherein said variable speed pump produces a sinusoidal fluid flow rate profile, said relative velocity effecting means including means for applying a variation in motor speed to said pump during said dispense phase according to a motor speed profile having a shape which is essentially inverted relative to said fluid flow rate profile to produce a substantially constant dispense velocity during dispensing step.

36. A clinical analyzer comprising:

a housing;

a metering system disposed within said housing for aspirating and dispensing at least one fluid into at least one reaction vessel for purposes of obtaining a reaction; and

a processing system for detecting at least one predetermined aspect of the reaction, said metering system including;

i) a proboscis retaining at least one of a plurality of metering tips;

ii) a fluid supply, and

iii) at least one pump fluidly interconnecting said at least one proboscis and retained metering tip and said fluid supply, said pump including a motor and mechanical means for producing a variable fluid flow rate profile for a constant motor speed during at least one phase of a metering cycle including a dispensing phase,

said analyzer further including means for effecting the relative velocity of fluid dispensed from said metering tip to modify a fluid flow rate of said pump during at least one phase of said metering cycle and thereby at least one of changing and modifying the variable fluid flow rate profile, wherein said variable speed pump produces a fluid flow rate profile in which the fluid flow rate during the dispensing phase is variable and characterized by an initially low fluid flow rate relative to the remaining portions of said profile, said relative velocity effecting means including means for increasing the speed of said pump motor during at least the beginning of said dispensing step so as to increase the fluid flow rate sufficiently to prevent perfusion of dispensed fluid relative to said dispense nozzle.