Abstract: A flow rate assembly can include a housing having a measurement channel extending along the housing axis and through a portion of the housing between the first and second ends of the housing, an outer cup portion positioned at least partly within the housing, and a transducer positioned within the outer cup portion and sealed from fluid flow past the outer cup portion, the transducer having a width perpendicular to the housing axis and greater than the width of the measurement channel, the transducer configured to generate an ultrasonic signal and to direct the ultrasonic signal through the measurement channel.

Abstract: A fluid-flow measuring apparatus is made of an enclosure housing that supports a plurality of flow-receiving tubes, each one of which has a plurality of apertures the either face substantially towards the source of fluid flow or away therefrom, a dispersing blade with a surface located in a plane that is parallel to a plane that is tangent to the surface of at least one of the plurality of flow-receiving tubes, a hub intersecting at least one of the plurality of flow-receiving tubes, and a facilitator structure that separates at least two of the plurality of flow-receiving tubes.

Abstract: An aircraft engine comprises an air inlet duct extending from an inlet through which air is configured to enter the aircraft engine, to an outlet within the aircraft engine. At least one strut has a leading edge and a trailing edge and extends across at least part of the air inlet duct. The at least one strut has a strut passage and a plurality of static pressure measurement taps spaced apart on the trailing edge and in fluid communication with the strut passage.

Abstract: An apparatus, system, and methods for measuring environmental parameters are disclosed. The apparatus, system and methods can be used for a variety of applications, including HVAC air balancing and building commissioning. The system includes a variety of wireless sensing modules and wearable modules for control. display, and storage. Parameters measured include air and water temperature, pressure. velocity, and flow. Also included are sensors for light intensity, CO concentrations, and CO2 concentrations.

Abstract: A flow rate assembly can include a fluid flow interface portion having a front facing wall and a back facing wall. The flow interface portion can include an inlet passage within the fluid flow interface portion, an outlet passage within the fluid flow interface portion, at least one inlet aperture extending through the front facing wall of the fluid flow interface portion into the inlet passage, and at least one outlet aperture extending through the back facing wall of the fluid flow interface portion into the outlet passage. In some cases, the fluid flow interface portion includes a plug forming at least a portion of the inlet passage.

Abstract: A system and method is provided for controlling building fluid distribution. The system may cause a variable air volume building ventilation system to operate at different combinations of different fan speeds for different damper opening configurations. For each different combination of fan speed and damper opening configuration, the system may: determine a static pressure measurement for each terminal unit based on a flow measurement determined by terminal box controllers using a pressure sensor; and determine a static pressure measurement for the supply fan from a pressure sensor mounted in a ventilation duct downstream of the at least one supply fan and upstream of each terminal unit. The system may also determine and store in each terminal box controller, a friction loss coefficient based on the static pressure measurements for the supply fan and the terminal units.

Abstract: A vane assembly may comprise a plurality of airfoils each extending between an inner platform and an outer platform, the plurality of airfoils comprising a nominal airfoil, a thickened airfoil, and a first thinned airfoil circumferentially adjacent to the thickened airfoil, wherein, the nominal airfoil has a first chord thickness, the thickened airfoil has a second chord thickness, and the thinned airfoil has a third chord thickness, wherein the second chord thickness is greater than the first chord thickness and the third chord thickness is less than the first chord thickness, and a member disposed within the thickened airfoil.

Abstract: A multi-function air data probe comprises a probe stem having an outer surface that extends between a first end and an opposite second end, with the probe stem having a first cross-sectional diameter; and a probe head having an outer surface that extends between a proximal end and a distal end, wherein the proximal end of the probe head is coupled to the first end of the probe stem. The probe head has a second cross-sectional diameter that is larger than the first cross-sectional diameter of the probe stem. A plurality of multi-hole ports is located in the probe head, with the multi-hole ports extending into and through the probe stem. The air data probe is operative to make measurements used to determine one or more of angle of attack values, total pressure values, and static pressure values.

Abstract: The present disclosure relates to a current rectifier for being arranged on the suction area of a ventilator, with an axial initial flow side and an axial exit flow side, wherein the current rectifier comprises several crossing struts formed by at least one circumferential strut and by at least one radial strut, and a pressure measuring conduit is constructed at least in one of the struts and which comprises at least one opening facing the exit flow side, and wherein the pressure measuring conduit comprises a measuring opening for being connected to a measuring line for the connection to a pressure sensor or a pressure sensor is integrated in the pressure measuring conduit.

Abstract: A flow conditioning system for a duct. The flow conditioning system includes a preconditioner that modifies upstream fluid flow that is maldistributed, providing predictable downstream flow to fluid flowing within the duct. The directional flow conditioner also includes a stationary flow geometry structure downstream of the preconditioner. The stationary flow geometry structure further conditions the upstream fluid flow from the preconditioner to provide a downstream flow with a substantially uniform flow profile. The flow conditioning system transforms upstream fluids having a maldistributed flow profile such as may be caused by a component, structure or obstruction within the duct to a substantially uniform flow profile downstream of the flow conditioning system within the available axial duct length so that the fluid may interact efficiently with equipment such as heat exchangers positioned within the duct downstream of the flow conditioning system.

Abstract: The invention relates to a device for controlling the swirl of a fluid (2, 7) flowing in a pipeline (1, 6), comprising a pipeline (1, 6) in which a fluid (2, 7) flows. The invention was based on the object of creating a device with which the adaptation of the swirl of a fluid (2, 7) flowing in a pipeline (1, 6) to the desired flow conditions in the pipeline (1, 6) is possible. Said object is achieved in that the device has at least one predetermined series of flow straighteners (5, 8) and swirl generators (4, 9, 10).

Abstract: A flow rate assembly can include a fluid flow interface portion having a front facing wall and a back facing wall. The flow interface portion can include an inlet passage within the fluid flow interface portion, an outlet passage within the fluid flow interface portion, at least one inlet aperture extending through the front facing wall of the fluid flow interface portion into the inlet passage, and at least one outlet aperture extending through the back facing wall of the fluid flow interface portion into the outlet passage. In some cases, the fluid flow interface portion includes a plug forming at least a portion of the inlet passage.

Abstract: A method of electroplating a metal foam includes placing a metal foam to be plated into an electroplating chamber with a plating material source, circulating an electrolyte through the chamber to carry metal ions from the plating material source, the circulating being selected and controlled to produce an even coating of plating material on surfaces of the metal foam.

Abstract: A golf club comprises a shaft, a club head, and a connection assembly that allows the shaft to be easily disconnected from the club head. In particular embodiments, the connection assembly includes a removable hosel sleeve that allows a shaft to be supported a desired predetermined orientation relative to the club head. In this manner, the shaft loft and/or lie angle of the club can be adjusted without resorting to traditional bending of the shaft. In another embodiment, the club head has an adjustable sole that can be adjusted upwardly and downwardly relative to the strike face of the club head, which is effective to adjust the face angle of the club head.

Abstract: Implementations of airflow capture hoods may include a central support coupled with a plurality of ribs configured to support a bottom end of a capture hood in an open position. The central support may be coupled with a plurality of poles configured to support an upper end of a capture hood in an open position.

Abstract: A method and apparatus for balancing terminals of an HVAC system uses an air flow measuring device by inputting into a computer processing portion of the air flow measuring device predetermined target flows for each terminal; acquiring via the air flow measuring device initially measured air flows through each of the terminals, the initially measured air flows being provided to the computer processing portion; and adjusting the terminals in the HVAC system to flow set points according to instructions from the computer processing portion, the computer processing portion being programmed to calculate the flow set point for each terminal given current HVAC system load conditions, that will result in all terminals being set to target flow after all terminals have been adjusted as instructed.

Abstract: A turbomachine airfoil component is disclosed, having a leading edge and a trailing edge. The airfoil component comprises a hole extending from an inlet positioned at the leading edge towards the interior of the airfoil component and forming a total pressure probe. The hole is fluidly connected to a pressure measuring device.

Abstract: The present application discloses a method and apparatus for testing vital capacity. The method comprises: measuring a static pressure P0 of a pressure hole inner cavity of a mobile device; wherein the pressure hole is communication with the exterior and is purposely disposed on the mobile device or is an already-designed opening; obtaining an air pressure P(t) at each moment by blowing air towards the pressure hole; obtaining an air flow speed v(t) corresponding to each moment according to a correspondence relation formula between the air flow speed v(t) and a pressure differential P(t)?P0; and obtaining vital capacity Vc of the subject according to a correspondence relationship between a measurement time t and the air flow speed v(t).

Abstract: An apparatus for obtaining pressure measurements in an airstream includes a Pitot tube. The Pitot tube includes at least one total pressure port configured to be positioned in the airstream facing upstream, at least one static pressure port configured to be positioned in the airstream facing downstream, at least one first directional port, and at least one second directional port. The at least one first directional port and the at least one second directional port are positioned on opposite sides of the at least one total pressure port and face obliquely with respect to the direction that the at least one total pressure port faces.

Abstract: A pressure probe includes a non-deflecting airfoil, a sensing feature, and an interior passage. The non-deflecting airfoil is made of a metal and configured for use in a gas turbine engine. The airfoil extends from a base to a tapered portion, and then to a linear portion, along a primary axis. The sensing feature is formed monolithically with the airfoil, as by additive manufacturing. The interior passage is operatively connected to the sensing feature and passes through both the airfoil and the base.

Abstract: An apparatus for measuring airflow through a diffuser of an HVAC system includes a hood for being positioned adjacent the diffuser so that airflow discharged from the diffuser is directed into the hood. The hood is configured to divide and direct the airflow through a plurality of discharge channels. Sensor probes measure the airflow through each discharge channel.

Abstract: A flow rate assembly can include a fluid flow interface portion having a front facing wall and a back facing wall. The flow interface portion can include an inlet passage within the fluid flow interface portion, an outlet passage within the fluid flow interface portion, at least one inlet aperture extending through the front facing wall of the fluid flow interface portion into the inlet passage, and at least one outlet aperture extending through the back facing wall of the fluid flow interface portion into the outlet passage. In some cases, the fluid flow interface portion includes a plug forming at least a portion of the inlet passage.

Abstract: A mass airflow measuring system includes an air conduit and a sensor assembly mounted to the air conduit, including a unitary one-piece first section which in cross section defines a first channel, a second channel and a wall separating the two channels. A second section has similar components. A unitary one-piece corner section, in cross section includes four legs, each defining a respective channel. A respective leg is mounted in a respective one of the channels of the first and second sections to communicate the sections with each other through the channels defined in the corner section legs. A sensor housing is mounted to one of the sections and includes an inlet opening communicating with the first channel and an exit opening communicating with the second channel. A mass airflow sensor communicates with a sample channel defined in the housing.

Abstract: An annular air flow passage for a turbine engine such as a turbojet or a turboprop, crossed by an instrumented rod that includes mechanism(s) for measuring characteristics of a flow potentially traveling along the passage, the rod extending between an outer annular wall and an inner annular wall of the passage. Outer connection(s) fasten(s) an outer end of the instrumented rod to the outer wall in a manner that is rigid in all directions, and inner connection(s) fasten(s) an inner end of the instrumented rod to the inner wall, in a manner that is rigid in the circumferential direction and that has at least one degree of freedom to move in a first direction extending between the inner and outer walls of the passage and having at least a radial component.

Abstract: A fluid transport system includes a housing defining a passageway for fluid to flow through the fluid transport system and a probe extending in the passageway. The probe includes a first end defining a plurality of sensing ports for the fluid to flow into the probe and a second end opposite the first end. The fluid flows through a plurality of conduits and a plurality of tubes. A differential pressure sensor is in fluid communication with the plurality of tubes such that the differential pressure sensor determines a differential pressure of the fluid in the plurality of tubes. A purge system is in fluid communication with the plurality of tubes. The purge system includes a source of purge liquid and is configured to direct the purge liquid through the plurality of tubes.

Abstract: A system for withdrawing samples of fluids comprises a pitot tube assembly, a flow sensor to measure a flow rate of the sample, and a pump connected to the pitot tube assembly to withdraw a sample, wherein the system is configured to match a sample flow velocity to the flow velocity sensed by a flow sensor on a pitot wand. The pitot tube assembly comprises a housing with a sample outlet and a return sample inlet, an extendable/retractable pitot wand within the housing, wherein the pitot wand includes a passage extending the length thereof to transfer a sample from a pitot tube end to a sealed compartment in the housing connected to the sample outlet; wherein the return sample inlet is connected to a passage in the housing leading to an outlet from the housing, and a flow sensor on an end of the pitot wand.

Abstract: A process variable transmitter is configured as a flowmeter for measuring flow of a process fluid through a conduit. The transmitter includes a pitot tube extending into the conduit which creates a differential pressure in the process fluid due to flow of the process fluid. An upstream process variable sensor is mounted on the pitot tube and coupled to the flow of process fluid to sense an upstream process variable of the process fluid. A downstream process variable sensor is mounted on the pitot tube downstream of the upstream process variable sensor and coupled to the flow of process fluid to sense a downstream process variable of the process fluid. Measurement circuitry determines the flow of the process fluid based upon the upstream process variable and the downstream process variable.

Abstract: Systems, apparatus and methods are disclosed for coupling an averaging picot tube (APT) primary element to a process pipe. A mounting assembly mounts the APT primary element to the process pipe such that a length of the APT primary element extending into the process pipe is adjustable to accommodate different sized process pipe diameters. The mounting assembly includes a weld coupling coupled to the process pipe over an opening in the process pipe and having the APT primary element extending therethrough into the process pipe. An extension pipe nipple is connected to the weld coupling and has the APT primary element extending therethrough such that a transition between a neck section and a sensor section of the APT primary element is positioned inside the extension pipe nipple. A union component, a ferrule, and a cap keep the APT primary element in the mounted position and form a process seal.

Abstract: A customizable duct mount averaging pitot tube (APT) assembly for use with a duct to measure a flow of fluid in the duct is provided. The APT assembly includes an APT primary element extending longitudinally between a first end and a second end. The APT primary element has first and second internal chambers extending longitudinally between the first and second ends. The APT primary element further includes an upstream face with an upstream opening which opens to the first internal chamber and extends from the first end to the second end, and a downstream face with a downstream opening which opens to the second internal chamber and extends from the first end to the second end. First and second duct mount flanges mount the respective first and second ends of the APT primary element to the duct when the APT primary element is inserted in the duct.

Abstract: A system for measuring hot or cold aisle containment air leakage in a data center includes a plurality of equipment enclosures arranged in a first row and a second row, a plurality of panels cooperatively arranged with the plurality of equipment enclosures to form an air containment region, and a conduit mounted within the air containment region and sealed at each end, the conduit having an orifice and a plurality of openings distributed at substantially uniform intervals along a length of the conduit.

Abstract: A customizable length averaging pitot tube (APT) probe for insertion into a confined conduit is disclosed. The APT probe includes a probe portion, configured to be inserted into the confined conduit, which includes longitudinally extending upstream, downstream and middle surfaces to form first and second fluid carrying plenums within the APT probe portion. A plurality of longitudinally arranged openings are disposed along the length of the upstream surface with each opening in fluid communication with the first fluid carrying plenum. A plurality of longitudinally arranged openings are disposed along the length of the downstream surface with each opening in fluid communication with the second fluid carrying plenum. A cap is affixed to an end of the APT probe portion to isolate the first and second fluid carrying plenums. An elongated body is coupled to the APT probe portion and provides fluid passageways fluidically coupled to the first and second plenums.

Abstract: Average pitot-tube type flow meter according to the present invention has a total pressure tube and a static pressure tube. The total pressure tube and the static pressure tube are spaced from each other. Across the total pressure tube and the static pressure tube, a rectifying device and a connection case are installed as they are integrated into one body. The rectifying device is positioned in advance of total pressure holes and the total pressure hole and a static pressure hole are positioned inside the connection case.

Abstract: This invention presents a Pitot tube design and methodology for determining the flow characteristics of fluids in subsonic and supersonic flow, including the effects of viscosity and turbulence. A new methodology, the Two-Fluid Theory, is developed which treats a real fluid as being composed of two ideal fluids: an inviscid fluid and a Poiseuille fluid. The resulting expression for flow velocity is applicable to a real fluid of any viscosity and to pipes of any L/D ratios, including entrance effects. Two designs, comprising annular, smooth-bore tubes, with devices for measuring total and static pressures, are presented: one for incompressible flow; one for compressible, supersonic flow. Allowance is made for the viscous component of the flow to become fully developed, in accordance with the Theory.

Abstract: A pressure measurement system for measuring pressure in a conduit has a bluff body extending into the conduit. The bluff body has an upstream opening and a downstream opening. An upstream pitot tube is slidably engaged within the bluff body and has an open end positioned in the upstream opening. A downstream pitot tube is slidably engaged within the bluff body and has an open end positioned in the downstream opening. A differential pressure sensor is fluidly coupled to the upstream pitot tube and the downstream pitot tube to measure a pressure difference between the upstream pitot tube and the downstream pitot tube.

Abstract: A temperature probe includes a flange, a support structure, thermocouple wires, and guide plates. The flange has a midline. The support structure is attached to the midline and extends away from the flange. The thermocouple wires extend along the support structure, and terminate in a set of outer sensing tips and a set of inner sensing tips. The guide plates secure the thermocouple wires to the support structure. The guide plates are offset laterally from the midline of the flange.

Abstract: A pressure measurement system for measuring pressure in a conduit has a bluff body extending into the conduit. The bluff body has an upstream opening and a downstream opening. An upstream pitot tube is slidably engaged within the bluff body and has an open end positioned in the upstream opening. A downstream pitot tube is slidably engaged within the bluff body and has an open end positioned in the downstream opening. A differential pressure sensor is fluidly coupled to the upstream pitot tube and the downstream pitot tube to measure a pressure difference between the upstream pitot tube and the downstream pitot tube.

Abstract: Apparatus and methods for measurement of airflow in a duct are described. The apparatus combines a Pitot tube, sensing apparatus, control apparatus, a display, control switches and carry apparatus arranged into a unitary structure.

Abstract: A fluid flow tool includes an airfoil structure and a support arm. The airfoil structure's high-pressure side and low-pressure side are positioned in a conduit by the support arm coupled to the conduit. The high-pressure and low-pressure sides substantially face opposing walls of the conduit. At least one measurement port is formed in the airfoil structure at each of its high-pressure side and low-pressure side. A first manifold, formed in the airfoil structure and in fluid communication with each measurement port so-formed at the high-pressure side, extends through the airfoil structure and support arm to terminate and be accessible at the exterior wall of the conduit. A second manifold, formed in the airfoil structure and in fluid communication with each measurement port so-formed at the low-pressure side, extends through the airfoil structure and support arm to terminate and be accessible at the exterior wall of the conduit.

Abstract: An apparatus and method for sensing position according to flow velocity includes at least two pitot tubes each defining a central axis is along mutually orthogonal axes. Each of at least two pressure sensors is positioned in fluid communication with a corresponding one of the at least two pitot tubes. A controller receives outputs from the at least two pressure sensors and analyzes to determine at least one of an angular and translational velocity according to the outputs. A distance traveled is then determined according to the at least one of an angular and translational velocity. Corresponding methods of use and calibration are also disclosed.

Abstract: A system for measuring hot or cold aisle containment air leakage in a data center includes a plurality of equipment enclosures arranged in a first row and a second row, a plurality of panels cooperatively arranged with the plurality of equipment enclosures to form an air containment region, and a conduit mounted within the air containment region and sealed at each end, the conduit having an orifice and a plurality of openings distributed at substantially uniform intervals along a length of the conduit.

Abstract: A sensor apparatus for measuring a pressure of an airflow in a duct. The sensor apparatus includes a first sensor portion that includes a first end and a second end, and that is without ports in communication with the airflow. The sensor also includes a second sensor portion that is coupled to the first sensor portion adjacent the first end, and a third sensor portion that is coupled to the first sensor portion adjacent the second end. The second sensor portion includes a first port that senses a first airflow pressure of the airflow, and a second port that senses a second airflow pressure of the airflow. The third sensor portion includes a third port that senses a third airflow pressure of the airflow, and a fourth port that senses a fourth airflow pressure of the airflow.

Abstract: An airflow sensor apparatus for measuring flow rate includes a pitot tube with a bypass channel wherein the pitot tube extends halfway into a flow channel in order to reduce a pressure drop. One or more upstream taps can be spaced along the pitot tube facing into a direction of a flow stream which directs the flow to the bypass channel. At least one or more downstream taps can be located to face perpendicular to the direction of flow, such that the fluid after passing over a flow sensor passes through the downstream tap(s). The upstream tap senses stagnation pressure and the down stream tap senses static pressure which is exerted in all directions in the flow channel in order to determine a velocity pressure based on a difference between pressures.

Abstract: A detector for monitoring the low levels of differential pressures and the rate of mass flow rate of gas (air, e.g.) in a duct. The sensor's temperature is maintained at a constant gradient above temperature of the flowing gas, typically 4-7° C. higher. The detector consists of two thermally decoupled sensors—one is the air temperature sensor and the other is a temperature sensor coupled to a heater. The sensors are connected to an electronic servo circuit that controls electric power supplied to the heater. The sensors are positioned outside of the air duct and coupled to the duct via a relatively thin sensing tube protruding inside the duct. The end of the tube has an opening facing downstream of the gas flow, thus being exposed to a static gas pressure.

Abstract: A pressure sensing probe having a probe body defining at least two bores communicating with respective bore entrance openings and bore exit openings therein for receiving a fluid flow into the bore entrance openings and through the bores. The bore entrance openings are aligned along an axis parallel with a longitudinal axis of the probe body for permitting alignment of the plurality of bore entrance openings along the plane of a longitudinal flow being sensed. The bore exit openings are adapted for communication with respective sensors for sensing the fluid flow and converting the fluid flow into a signal for downstream signal processing.

Abstract: A differential static pressure measuring or activating device measuring fluid flow through a duct including two pitot tubes each including a proximal end connected to a valve, a distal end portion located in the duct extending generally parallel to each other and perpendicular to the air flow through the duct having open distal ends and a plate located between the distal end portions of the tubes creating a differential static pressure between the open ends of the tubes. The open distal ends of the tubes incline toward the plate such that the open ends face toward and away from the direction of the gas flow through the duct.

Abstract: Apparatus and methods for airflow testing, especially for air testing of gas turbine components on an airflow test bench. Various embodiments of the present invention include the use of a measurement section downstream of the component being tested. The measurement section, in one embodiment, includes apparatus for measurement of gas properties at a plurality of spaced-apart radial locations and/or a plurality of spaced-apart circumferential locations. In another embodiment, the invention includes a method for testing a component including a comparison of gas properties measured in both forward and reverse flow directions.

Abstract: Disclosed is an apparatus for measuring respiratory gas flow, which provides a high accuracy in measurement of the respiratory gas flow and reduces the manufacturing cost of the apparatus, in comparison with the conventional disposable apparatus for measuring respiratory gas. The apparatus includes a measurement module and a respiratory tube assembly. The respiratory tube assembly comprise a cylindrical tube body and a sensing rod inserted through the cylindrical tube body. The sensing rod is shaped like the number “1” and has a plurality of sampling pores and two air passages. Locations of the sampling pores are determined by equal area division method in which a circular section of the cylindrical tube body is divided into a plurality of annuluses with equal areas and the sampling pores are formed at the positions also equally dividing the annuluses to which the sampling pores belong.

Abstract: An electric pressure probe for an aircraft comprises: a pitot tube assembly for collecting pneumatically air pressure in the vicinity of the assembly; a strut including one end mountable to a surface of the aircraft, the pitot tube assembly being coupled to another end of the strut for being supported away from the aircraft surface; a pressure sensor integral to the strut and pneumatically coupled to the pitot tube assembly for converting the pneumatic pressure collected thereby to an electrical pressure signal; and circuitry integral to the strut and coupled to the pressure sensor for signal conditioning the electrical pressure signal, the circuitry including at least one output lead for conducting the conditioned electrical signal from the probe.

Abstract: Apparatus for measuring the viscosity of a Newtonian fluid, includes a tubular housing which defines an internal cavity; a fluid restriction structure disposed in a first portion of the cavity; and a pressure measuring device disposed to measure the differential pressure in the cavity of the fluid which has flowed through the fluid restriction structure. The apparatus further includes a device for applying pressure to the fluid upstream from the fluid restriction structure to cause the fluid to flow through the fluid restriction structure so that the pressure measuring device measures the pressure differential which is inversely proportional to the fluid viscosity squared.

Abstract: Disclosed is an apparatus for measuring respiratory gas flow, which provides a high accuracy in measurement of the respiratory gas flow and reduces the manufacturing cost of the apparatus, in comparison with the conventional disposable apparatus for measuring respiratory gas. The apparatus includes a measurement module and a respiratory tube assembly. The respiratory tube assembly comprise a cylindrical tube body and a sensing rod inserted through the cylindrical tube body. The sensing rod is shaped like the number “1” and has a plurality of sampling pores and two air passages. Locations of the sampling pores are determined by equal area division method in which a circular section of the cylindrical tube body is divided into a plurality of annuluses with equal areas and the sampling pores are formed at the positions also equally dividing the annuluses to which the sampling pores belong.