Measuring system for a medium flowing in a process line

• US 20080072688A1
• Filed: 07/19/2007
• Published: 03/27/2008
• 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
• Granted Patent: US 7,600,436 B2
• Time in Patent Office: Days
• US Class Current: 73/861.64
• 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

The measuring system is inserted into the course of a process line and serves for registering at least one measured variable of a medium flowing in the process line. The measuring system includes for such purpose a measuring transducer having a measuring tube serving for conveying medium being measured and a sensor arrangement, which has at least one sensor element reacting primarily to the measured variable to be registered, and which delivers by means of at least one sensor element at least one measurement signal influenced by the measured variable. Further, the measuring system includes a measuring electronics communicating with the measuring transducer and using the at least one measurement signal for producing, at least at times, at least one measured value instantaneously representing the measured variable. The measuring tube has, in the case of the measuring system of the invention, a smaller flow cross section than a supply segment of the process line connected to the inlet end of the measuring system. To this end, the measuring system further includes a flow conditioner arranged at the inlet end of the measuring tube and mediating between the measuring tube and the supply segment of the process line. The flow conditioner has a lumen tapering in the direction of the measuring tube. During operation, medium flows through the lumen of the flow conditioner. The flow conditioner includes at least one impingement surface arranged upstream of its outlet end and protruding into the lumen of the flow conditioner. During operation, medium conveyed in the flow conditioner flows against the impingement surface.

Claims

1-86. -86. (canceled)

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

an inlet;

a measuring transducer including a measuring tube and a sensor arrangement with at least one sensor element reacting primarily to the variable to be registered, said measuring tube serving for conveying the medium to be measured and said measuring tube having a smaller flow cross section 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, wherein;

said flow conditioner mediating between said measuring tube and the supply segment of the process line and having a lumen, which tapers toward said measuring tube and through which medium flows during operation;

said flow conditioner including an inlet end facing the supply segment of the process line and having 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 having a flow cross section, which is smaller than the flow cross section of the inlet end of the flow conditioner; and

said flow conditioner further includes, 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.

88. The measuring system as claimed in the claim 87, wherein:

the impingement surface is so arranged and so oriented in said flow conditioner that it is at least sectionally essentially perpendicular to a longitudinal axis of said flow conditioner; and

/or

the impingement surface is so arranged and so oriented in said flow conditioner that it is at least sectionally essentially perpendicular to a longitudinal axis of said measuring tube; and

/or

the impingement surface shows a height in the radial direction of at least 1 mm; and

/or

the impingement surface is an annular surface; and

/or

the impingement surface and the inner edge are, at least in part, formed by a shoulder formed in the inlet of said flow conditioner; and

/or

the impingement surface is at least sectionally essentially planar; and

/or

the impingement surface is so arranged and oriented in said flow conditioner that it is sectionally essentially coplanar with a cross section of said flow conditioner; and

/or

the impingement surface is so arranged and oriented in said flow conditioner that it is sectionally essentially coplanar with a cross section of said measuring tube; and

/or

the impingement surface is at least sectionally essentially conical; and

/or

the impingement surface tapers toward said measuring tube; and

/or

the impingement surface widens towards the inlet end of said flow conditioner; and

/or

the impingement surface of said flow conditioner is arranged in a annular border region of said flow conditioner; and

/or

said flow conditioner is formed essentially circular-cylindrically, at least in an inlet region; and

/or

said flow conditioner is formed essentially circular-cylindrically, at least in an outlet region; and

/or

said measuring tube is formed essentially circular-cylindrically, at least in an inlet region; and

/or

said measuring tube is essentially straight; and

/or

said measuring tube is essentially circular-cylindrical; and

/or

said process line is a pipeline; and

/or

a cross section 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

a cross section 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 smaller than 10; and

/or

a cross section ratio of the flow cross section of said 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.

89. The measuring system as claimed in claim 88, wherein:

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

/or

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

/or

said impingement surface is embodied as a spherically formed and/or cleft annular surface.

90. The measuring system as claimed in claim 89, wherein:

said impingement surface is embodied as multiply serrated surface; and

/or

said impingement surface is embodied as waved surface.

91. The measuring system as claimed in claim 87, wherein:

said at least one sensor element comprises at least one piezoelectric element; and

/or

said at least one sensor element comprises at least one piezoresistive element; and

/or

said least one sensor element comprises at least one solenoidal coil corresponding with an armature; and

/or

said at least one sensor element comprises at least one measuring electrode contacting medium flowing in said measuring tube and sensing electric potentials; and

/or

said at least one sensor element comprises at least one measuring capacitor reacting to changes of the measured variable; and

/or

said at least one sensor element comprises at least one electrical resistor; and

/or

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; and

/or

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

/or

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.

92. The measuring system as claimed in claim 87, wherein:

said measuring transducer comprises at least one bluff body arranged in said measuring tube, and the at least one sensor element of the sensor arrangement is arranged downstream from said at least one bluff body.

93. The measuring system as claimed in claim 87, wherein:

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

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.

94. The measuring system as claimed in claim 87, wherein:

said flow conditioner further includes, arranged upstream of its outlet end, at least one inner edge protruding into said lumen of said flow conditioner against which medium, conveyed in said flow conditioner, flows during operation

95. The measuring system as claimed in the claim 94, wherein:

said at least one inner edge protruding into said lumen of said flow conditioner is so formed and so arranged in said flow conditioner, that it is oriented essentially transversely to a longitudinal axis of said flow conditioner;

said at least one inner edge protruding into said lumen of said flow conditioner is so formed and so arranged in said flow conditioner, that it is oriented essentially transversely to a longitudinal axis of said measuring tube; and

/or

said at least one inner edge protruding into said lumen of said flow conditioner extends circumferentially around said flow conditioner and, as a result, closes on itself; and

/or

said at least one inner edge protruding into said lumen of said flow conditioner is arranged in the vicinity of the inlet end of said flow conditioner; and

/or

said at least one inner edge protruding into said lumen of said flow conditioner is located immediately at the inlet end of said flow conditioner; and

/or

a cross section of said lumen of said flow conditioner bounded by the inner edge protruding into said lumen of said flow conditioner has a diameter, which is smaller than the caliber of the supply segment of said process line; and

/or

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; and

/or

the inner edge shows a serrated contour; and

/or

the inner edge shows a waved contour; and

/or

the at least one inner edge protruding into said lumen of said flow conditioner has an edge radius smaller than 2 mm; and

/or

a contraction 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

a contraction ratio of the cross section bounded by the inner edge to the flow cross section of said measuring tube is kept smaller than 5; and

/or

a contraction ratio of the 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.

96. The measuring system as claimed in claim 87, wherein:

said measuring tube has a smaller caliber than a supply segment of the process line attached to the inlet end of the measuring system.

97. The measuring system as claimed in claim 96, wherein:

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

/or

a caliber 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

a caliber ratio of the caliber of the supply segment of said process line to the caliber of said measuring tube is kept smaller than 5; and

/or

a caliber 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.

98. The measuring system as claimed in claim 87, wherein:

said measuring tube has an installed length, which is greater than an installed length of said flow conditioner, so that an installed length ratio of the installed length of said flow conditioner to the installed length of said measuring tube is kept smaller than one.

99. The measuring system as claimed in claim 98, wherein:

a caliber ratio of the caliber of the supply segment of said process line to the caliber of said measuring tube corresponds to at least 10% of the installed length ratio of the installed length of said flow conditioner to the installed length of said measuring tube.

100. The measuring system as claimed in claim 87, wherein:

the at least one sensor element is arranged at a distance from the inlet end of said measuring tube in and/or on said measuring tube that a ratio of said distance to a caliber of said measuring tube is kept greater than one.

101. The measuring system as claimed in claim 100, wherein:

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

/or

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

102. The measuring system as claimed in claim 94, wherein:

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

103. The measuring system as claimed in claim 102, wherein:

the impingement surface and the inner edge are, at least in part, formed by a circular and/or self-closing shoulder formed in the inlet of said flow conditioner.

104. The measuring system as claimed in claim 103, wherein:

the impingement surface and the inner edge are formed at least partially by an inner cone formed into the inlet in said flow conditioner.

105. The measuring system as claimed in claim 104, wherein:

the inner cone forming the impingement surface has a flank angle, which is greater than 45°

; and

/or

wherein the inner cone forming the impingement surface shows a flank angle smaller than 90°

; and

/or

the inner cone forming the impingement surface has a flank angle greater than 60° and

smaller than 88°

; and

/or

the inner cone extends to the inlet end of said flow conditioner and tapers toward said measuring tube.

106. The measuring system as claimed in claim 94, wherein:

the impingement surface and the inner edge are formed at least partially by an inner cone formed into the inlet in said flow conditioner.

107. The measuring system as claimed in claim 106, wherein:

the inner cone extends to the inlet end of said flow conditioner and tapers toward said measuring tube.

108. The measuring system as claimed in claim 94, wherein:

the at least one inner edge protruding into said lumen of said flow conditioner limits a guide surface of said flow conditioner extending in the direction of the outlet end of said flow conditioner and serving for guiding medium flowing in said flow conditioner.

109. The measuring system as claimed in claim 108, wherein:

the guide surface of said flow conditioner is formed, at least sectionally, convexly; and

/or

the guide surface of said flow conditioner is formed, at least sectionally, concavely; and

/or

the guide surface of said flow conditioner has an essentially S-shaped contour; and

/or

the guide surface of said flow conditioner tapers toward said measuring tube; and

/or

the guide surface of said flow conditioner is formed essentially conically; and

/or

the guide surface and the inner edge are formed, at least in part, by an inner cone formed in the inlet of said flow conditioner.

110. The measuring system as claimed in claim 109, wherein:

the inner cone forming the guide surface of said flow conditioner has a flank angle greater than 2°

; and

/or

the inner cone forming the guide surface of said flow conditioner has a flank angle smaller than 45°

; and

/or

the inner cone forming the guide surface of said flow conditioner has a flank angle greater than 4° and

smaller than 10°

; and

/or the guide surface of said flow conditioner is formed, at least sectionally, conically; and

/or

the guide surface and the inner edge are formed, at least in part, by an inner cone extending to the outlet end of said flow conditioner.

111. The measuring system as claimed in claim 108, wherein:

the impingement surface is formed by a first inner cone formed into the inlet of said flow conditioner and extending toward its inlet end, and the guide surface is formed by a second inner cone formed into the inlet of said flow conditioner and extending toward its outlet end.