Measuring system with a flow conditioner arranged at an inlet of a measuring tube

• US 7,926,361 B2
• Filed: 09/23/2009
• Issued: 04/19/2011
• Est. Priority Date: 07/21/2006
• Status: Active Grant

• Current Assignee: Endress+Hauser Flowtec AG (Endress+Hauser AG)
• Original Assignee: Endress+Hauser Flowtec AG (Endress+Hauser AG)
• Inventors: Hoecker, Rainer
• Primary Examiner(s): PATEL, HARSHAD R
• Application Number:
  US12/585,719
• Publication Number:
  US 20100037704A1
• Time in Patent Office: 573 Days
• Field of Search: None
• US Class Current: 73/861.22
• CPC Class Codes: G01F 1/3209 using Karman vortices
• CPC Class Codes: G01F 1/86 Indirect mass flowmeters, e.g. measuring volume flow and density, temperature or pressure
• CPC Class Codes: G01F 1/88 with differential-pressure measurement to determine the volume flow
• CPC Class Codes: G01F 15/00 Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
• CPC Class Codes: G01F 15/185 Connecting means, e.g. bypass conduits

Abstract

A measuring system for registering a measured variable of a flowing medium. A measuring transducer, a sensor arrangement, measuring electronics, a measuring tube and a flow conditioner are included. The sensor arrangement has at least one sensor element which delivers at least one measurement signal. The measuring electronics communicates with the measuring transducer and using the at least one measurement signal produces at least one measured value representing the measured variable. The flow conditioner has lumen tapering in the direction of the measuring tube. During operation, medium flows through the lumen and against an impingement surface of the flow conditioner.

Claims

1. A measuring system for registering at least one measured variable of a medium flowing in a process line, said measuring system comprising:

an inlet;

a measuring transducer including a measuring tube and a sensor arrangement with at least one sensor element reacting to the variable to be registered, said measuring tube serving for conveying the medium to be measured and said measuring tube showing a flow cross section smaller than a supply segment of the process line connected to said inlet of the measuring system, and said measuring transducer providing, by means of the at least one sensor element, at least one measurement signal influenced by the measured variable;

measuring electronics communicating with said measuring transducer and producing, at least at times, taking into consideration the at least one measurement signal, at least one measured value instantaneously representing the measured variable; and

a flow conditioner arranged at an inlet of said measuring tube, said flow conditioner mediating between said measuring tube and the supply segment of the process line and showing a lumen, which tapers toward said measuring tube and through which medium flows during operation, wherein;

said flow conditioner including an inlet end facing the supply segment of the process line and showing a flow cross section, which is greater than the flow cross section of said measuring tube;

said flow conditioner including an outlet end facing toward said measuring tube and showing a flow cross section, which is smaller than the flow cross section of the inlet end of the flow conditioner;

said flow conditioner including, arranged upstream of its outlet end, at least one impingement surface, which protrudes into the lumen of the flow conditioner and against which medium, conveyed in the flow conditioner, flows during operation; and

said at least one inner edge protruding into said lumen of said flow conditioner is formed by keeping the inner diameter of the inlet end of said flow conditioner smaller than the caliber of the supply segment of said process line.

2. The measuring system as claimed in the claim 1, wherein:

the impingement surface shows a height in the radial direction of at least 1 mm, and/or the impingement surface is at least sectionally essentially planar.

3. The measuring system as claimed in the claim 1, wherein:

a cross section ratio, defined by a ratio of the flow cross section of the supply segment of said process line to the flow cross section of said measuring tube is kept greater than 1.5 and/or smaller than 10

a contraction ratio, defined by a ratio of a cross section bounded by the inner edge to the flow cross section of said measuring tube is kept greater than 1.2 and/or smaller than 5; and

a caliber ratio, defined by a ratio of the caliber of the supply segment of said process line to the caliber of said measuring tube is kept greater than 1.1, and/or smaller than 5.

4. The measuring system as claimed in claim 3, wherein:

a caliber ratio, defined by a ratio of the caliber of the supply segment of said process line to the caliber of said measuring tube is kept greater than 1.1 and smaller than 5.

5. The measuring system as claimed in claim 3, wherein:

a cross section ratio, defined by a ratio of the flow cross section of the supply segment of said process line to the flow cross section of said measuring tube is kept greater than 1.5 and smaller than 10.

6. The measuring system as claimed in claim 1, wherein:

said at least one sensor element is immersed in the medium during operation.

7. The measuring system as claimed in claim 1, wherein:

said at least one sensor element is arranged directly on said measuring tube.

8. The measuring system as claimed in claim 1, wherein:

said at least one sensor element comprises at least one of;

a piezoelectric element, a piezoresistive element,

a solenoidal coil corresponding with an armature,

a measuring electrode contacting medium flowing in said measuring tube and sensing electric potentials

a capacitor reacting to changes of the measured variable

and an electrical resistor.

9. The measuring system as claimed in claim 1, wherein:

said measuring transducer comprises at least one bluff body arranged in said measuring tube.

10. The measuring system as claimed in claim 1, wherein:

the at least one measured value, produced by said measuring electronics, is selected from a group consisting of;

a mass flow measured value, a volume flow measured value, a density measured value, a viscosity measured value, a pressure measured value, and a temperature measured value.

11. The measuring system as claimed in claim 1, wherein:

said measuring transducer comprises a transducer selected from a transducer group consisting of;

is embodied as a vortex flow transducer, a magneto-inductive flow transducer, a flow transducer of vibration-type, especially a Coriolis mass flow transducer, a density transducer, a viscosity transducer, and an ultrasonic flow transducer.

12. The measuring system as claimed in the claim 1, wherein:

the at least one inner edge protruding into said lumen of said flow conditioner shows an edge radius smaller than 2 mm.

13. The measuring system as claimed in claim 1, wherein:

the inlet end of said flow conditioner facing the supply segment of the process line shows a caliber greater than a caliber of said measuring tube, and the outlet end of said flow conditioner facing said measuring tube shows a caliber smaller than the caliber of the inlet end of said flow conditioner.

14. The measuring system as claimed in claim 1, wherein:

said at least one inner edge protruding into said lumen of said flow conditioner limits the impingement surface of said flow conditioner.

15. The measuring system as claimed in claim 1, wherein:

said at least one sensor element is subjected during operation repeatedly to mechanical deformations influenced by the medium flowing in said measuring tube; and

/or said at least one sensor element is moved during operation repeatedly relative to a static, rest position under influence of medium flowing in said measuring tube.

16. The measuring system as claimed in claim 1, wherein:

a cross section ratio, defined by a ratio of the flow cross section of the supply segment of said process line to the flow cross section of said measuring tube is kept greater than 1.5 and smaller than 10.

17. The measuring system as claimed in claim 1, wherein:

a cross section ratio, defined by a ratio of the flow cross section of the supply segment of said process line to the flow cross section of said measuring tube is kept in a range between 1.66 and 9.6.

18. The measuring system as claimed in claim 1, wherein:

a contraction ratio, defined by a ratio of a cross section bounded by the inner edge to the flow cross section of said measuring tube is kept in a range between 1.3 and 3.

19. The measuring system as claimed in claim 1, wherein:

a caliber ratio, defined by a ratio of the caliber of the supply segment of said process line to the caliber of said measuring tube is kept greater than 1.1 and smaller than 5.

20. The measuring system as claimed in claim 1, wherein:

a caliber ratio, defined by a ratio of the caliber of the supply segment of said process line to the caliber of said measuring tube is kept in a range between 1.2 and 3.1.