Abstract: An apparatus for sensing the level of a liquid includes a float, a tether attached to the float, a pulley attached to the tether, a rotation sensor connected to the pulley that senses vertical movement of said float and senses the level of the liquid.

Abstract: A method to balance a wheel assembly. In a first aspect, corrective balance weights and position thereof are determined by a balancer and a closest corrective balance weight thereto is chosen, as well as one of higher and one of lower weight increment for each plane; chosen weights are paired to provide minimized residual and then attached to the planes of the wheel assembly. In a second aspect, imbalance weights are determined by a balancer; a pair of corrective balance weights, one at least ½ the determined imbalance weight are chosen, each separated by determined position angles to minimize residual and then respectively attached to the corrective balance plane(s) of the wheel assembly.

Abstract: An apparatus for rotatably mounting a rotor to be balanced is provided. The apparatus include a rotatably mounted balancing spindle to which the rotor to be balanced is to be non-rotatingly connected, at least one bearing block, a plurality of spring bars aligned parallel to the spindle axis and used to mount the balancing spindle on the bearing block such that the balancing spindle is able to vibrate, and a drive mechanism for the balancing spindle. The spring bars are arranged in more than two planes at different distances from the spindle or in planes having different rotary angular positions about the spindle axis.

Abstract: A yaw-rate sensor having a substrate and a plurality of movable substructures that are mounted over a surface of the substrate, the movable substructures being coupled to a shared, in particular, central spring element, means being provided for exciting the movable substructures into a coupled oscillation in a plane that extends parallel to the surface of the substrate, the movable substructures having Coriolis elements, means being provided for detecting deflections of the Coriolis elements induced by a Coriolis force, a first Coriolis element being provided for detecting a yaw rate about a first axis, a second Coriolis element being provided for detecting a yaw rate about a second axis, the second axis being oriented perpendicularly to the first axis.

Abstract: A MEMS sensor capable of sensing acceleration and pressure includes a frame, a proof mass and flexible bridges connected between the frame and the proof mass in such a way that the proof mass is moveably suspended inside the frame. The proof mass is provided with a pressure sensing diaphragm and a sealed chamber corresponding to the diaphragm such that the proof mass is not only served as a moveable sensing element for acceleration measurement but also a pressure sensing element.

Abstract: Disclosed are apparatus and methodologies for detecting inversion tamper, removal tamper, and taps using a three-axes accelerometer sensor in a utility meter environment. Inversion tamper is detected upon power up if the acceleration value along Y axis is greater than or equal to some small positive threshold. Removal tamper is detected if the average acceleration change of both Y and Z axes is greater than or equal to the removal threshold. A tap is detected if the average acceleration change along the X axis is greater than or equal to the tap threshold. The initial acceleration values are set upon power up. Removal tamper detection and tap detection are distinguished using a moving average filter. Tap detection uses timing constraints to avoid false tap detections.

Abstract: A vibration transducer includes a silicon single crystal vibration beam provided over a silicon single crystal substrate, the vibration beam having a sectional shape that is longer in a direction perpendicular to a surface of the silicon single crystal substrate than in a direction parallel with it, a shell made of silicon, surrounding the vibration beam with a gap, and forming a vacuum room together with the silicon single crystal substrate, a plate-like first electrode plate disposed parallel with the surface of the silicon single crystal substrate, the first electrode plate having one end connected to the vibration beam, plate-like second and third electrode plates disposed parallel with the surface of the silicon single crystal substrate so as to be opposed to each other with the vibration beam interposed in between, and asperities formed on confronting side surfaces of the vibration beam and the second and third electrode plates.

Abstract: A passage detection apparatus is configured to detect the change in the properties (propagation state of sound wave, dielectric constant, etc.) of a specific space, which changes according to the passage of an object in the specific space and the size of the object. The passage detection apparatus includes a pair of detection units and configured to transmit and receive signals to and from an external device. The specific space is formed by the space between the detection unit and the detection unit. The detection unit is supported by a first substrate. The detection unit is supported by a second substrate that is parallel to the first substrate, and arranged at the position corresponding to the detection unit supported by the first substrate.

Abstract: A non-destructive inspection scanning apparatus and a non-destructive inspection apparatus which can cope with the size and shape of a structure, which is an inspection target, in which attachment to the structure is facilitated, and which can be reduced in size and cost are provided.

Abstract: The embodiments of the probe or the probe handle additionally include an integrally formed cooling structure with at least one dividing wall that is connected to an outer wall and an inner wall of the probe. The outer wall and the inner wall of the probe together form a medium flow space inside the probe, and the dividing wall divides the medium flow space into a continuous medium flow path where a predetermined medium travels to carry undesirable heat away from the probe handle. The undesirable heat is generated from electronic components and or an array of transducer elements in the probe handle.

Abstract: An inspection vehicle for inspecting a substantially cylindrical object composed of a magnetizable material includes a chassis. A plurality of wheels is disposed on the chassis so as to be rotatable and is configured to move the chassis in a circumferential direction along an external surface of the cylindrical object, at least some of the plurality of wheels being motor-drivable. The plurality of wheels is disposed so as to provide a chassis clearance allowing a movement of the chassis over an obstruction on the external surface of the cylindrical object. A magnetic device is disposed on the chassis and is configured to hold the vehicle on the external surface of the cylindrical object.

Abstract: The invention relates to a test probe 10 for the non-destructive testing of a workpiece by means of ultrasonic sound. The test probe has an ultrasonic transducer 20 for the generation of an ultrasonic field, which is coupled acoustically to a delay line body 12, which is provided to be attached for a coupling of the ultrasonic field into the workpiece on a surface of the workpiece. Furthermore, the invention relates to a family of test probes as well as to a testing device for the non-destructive testing of a workpiece by means of ultrasonic sound, with a test probe 10, whose ultrasonic transducer 20 has a majority of independently controllable individual oscillators. Furthermore, a control unit 50 is provided, which is equipped to control the individual oscillators of the ultrasonic transducer 20 with phase accuracy in such a way, that a sound field rotationally symmetrical to the central beam is generated.

Abstract: A technology is disclosed which provides an array scanning type ultrasound probe capable of preventing a diminution of ultrasound of a piezoelectric device at the time of transmission and at the time of reception due to its damage and thereby reducing a sensitivity deterioration of a diagnostic image. According to the technology, included are an electroacoustic conversion unit formed by arranging multiple piezoelectric devices and multiple acoustic matching layers in a predetermined direction, each of the multiple piezoelectric devices being an electroacoustic conversion device, the multiple acoustic matching layers being respectively stacked on the multiple piezoelectric devices; and a signal flexible board transferring electric signals to be transmitted to and received from the multiple piezoelectric devices.

Abstract: An image sensing device according to the present invention includes: an optical portion that is driven to form an optical image in any state; a sensor portion that acquires, as an image signal, the optical image formed by the optical portion; a sound collection portion that acquires an acoustic signal by collecting sound; an image sensing environment determination portion that determines an image sensing environment which is an environment under which the sensor portion acquires the image signal; and an operation determination portion that determines, based on the image sensing environment determined by the image sensing environment determination portion, at least one of a drive speed of the optical portion and a method of processing the acoustic signal acquired by the sound collection portion when the optical portion is driven.

Abstract: The present invention provides novel apparatus and methods for fast quantitative measurement of perturbation of optical fields transmitted, reflected and/or scattered along a length of an optical fibre. The present invention can be used for point sensors as well as distributed sensors or the combination of both. In particular this technique can be applied to distributed sensors while extending dramatically the speed and sensitivity to allow the detection of acoustic perturbations anywhere along a length of an optical fibre while achieving fine spatial resolution. The present invention offers unique advantages in a broad range of acoustic sensing and imaging applications. Typical uses are for monitoring oil and gas wells such as for distributed flow metering and/or imaging, seismic imaging, monitoring long cables and pipelines, imaging within large vessel as well as for security applications.

Abstract: An electrodynamic shaker apparatus is disclosed for providing shaking and/or vibrational motion. The shaker includes armature and stator assemblies as well as a distributed spring assembly. The shaker apparatus of the present invention is robust, supports increased off-center loads, and has a low profile such that it may be easily placed under an item of furniture in order to impart vibrational motion in response to electrical signals from a variety of sources.

Abstract: A resonant sensor is disclosed which may be arranged to measure the pressure of a fluid. The resonant sensor comprises a diaphragm which may be exposed to a fluid; two supports provided on the diaphragm and a resonator having at least two beams with each beam being suspended between the two supports. The ends of each beam are attached to a corresponding support at more than one point. By attaching each end of the beams to a support at more than one point, the moments and reaction forces to which the support is subjected may be balanced so that distortion of the support and diaphragm due to vibration of the resonator beams is reduced. Consequently, the resonant sensor is able to provide more precise measurements.

Abstract: There is disclosed a high pressure sensing header which is relatively insensitive to mounting torque. The header generally includes an outer torque isolating shell which has a “C” shaped cross section with the cylindrical shell surrounding an inner “H” section header. The inner “H” section header has a thick diaphragm and is at least partially surrounded by the torque isolating shell. In this manner, when the header is installed, the installation force is absorbed by the outer shell and there is relatively no installation force or torque exhibited by the inner “H” section which will respond only to stress due to pressure.

Abstract: A tunable pressure transducer assembly that comprises a sensing element disposed within a housing, wherein the sensing element is adapted to output a signal substantially indicative of an applied pressure, and a filter assembly also disposed within the housing. The filter assembly comprises a cap and a tube, wherein the cap is spaced from the sensing element within the housing such that it encloses a set volume around the sensing element, and wherein the tube controls access of the applied pressure to the set volume. The filter assembly is operative to substantially reduce high frequency pressure ripples and allow static and quasi-static pressures to pass through to the sensing element, and may be manipulated to tune the pressure transducer assembly to achieve a desired dampening frequency. The filter assembly therefore enables one pressure transducer assembly outline to accurately measure pressure in various systems.

Abstract: The invention relates to a device for investigating the statistical variability of an axial load gauge. The device is inserted into an axial load gauge and a load is gradually applied. At a preset load, a mechanism within the device controllably collapses and the applied load is safely transmitted through the structure of the device. A comparison of the load measured on the device load cell against that measured on the gauge load cell facilitates calculation of the repeatability and reproducibility of the axial load gauge. The test is non-destructible and highly repeatable; it permits comparison of load measurements made on different axial load gauge types and in different factories.

Abstract: A fatigue sensor for monitoring the health state of structural members is disclosed. The sensor has multiple parallel beams, each sensitive to different levels of fatigue, that are designed to fail prematurely but progressively as the sensor goes through the same fatigue cycles as the structural member it is attached to. Whenever fatigue levels on a particular beam of the sensor exceed the engineered number of fatigue cycles, that particular beam fails and sensor electronics can detect that failure and transmit this information wirelessly when interrogated by an external interrogator. Having multiple beams that fail after different numbers of fatigue cycles enables the health state of the structural member to be monitored, in that unlike normal fracture sensor that sense failure of the structural members after the actual fracture event, the present invention is capable of sensing imminent failure of the structural member before the actual failure occurs.

Abstract: Systems and methods for controlling and monitoring flow of a desired fluid are disclosed. An in vitro pulsatile flow system has a fluid reservoir that contains the desired fluid, which simulates a physiologic fluid, such as cerebrospinal fluid. A pump transports the desired fluid from the fluid reservoir to a test material to permit monitoring of adhesion of cells and tissue to the test material.

Abstract: The invention relates to a method of operating an ultrasonic gas flow meter, the ultrasonic gas flow meter including at least one signal evaluation unit, at least one memory, a piping through which gas can flow, at least one pair of ultrasonic transducers disposed on opposite sides of the piping and separated by a path inclined to a flow direction of the piping, wherein each ultrasonic transducer is connected to an electronic circuit to selectively act as an ultrasonic transmitter and an ultrasonic receiver, wherein the ultrasonic gas flow meter is adapted to detect a flow velocity of the gas flowing through the piping on the basis of differences between propagation times of ultrasonic signals transmitted and received between each pair of transducers and propagating in opposite directions along the path, wherein the method includes a test procedure for verifying the operation of electronics associated with the ultrasonic gas flow meter wherein, when the test procedure is activated, test signals are triggered

Abstract: A variable flow resistance system can include a vortex device, with resistance to flow of a fluid composition through the vortex device being dependent on a rotation of the fluid composition at an inlet to the vortex device. Another system can include a second vortex device which receives a fluid composition from an outlet of a first vortex device, a resistance to flow of the fluid composition through the second vortex device being dependent on a rotation of the fluid composition at the outlet. Another system can include a first vortex device which causes increased rotation of a fluid composition at an outlet thereof in response to an increase the fluid composition velocity, and a second vortex device which receives the fluid composition from the outlet, a flow resistance through the second vortex device being dependent on the rotation of the fluid composition at the outlet.

Abstract: A mudline riser annulus flow meter includes a liner configured to be attached to a riser to cover a hole; a cover configured to be attached to the riser to cover the liner such that a cavity is formed by the liner and the cover; a sensor rod configured to be attached to the liner and to extend inside cavity, the sensor rod having a bore; a magnet assembly configured to be fixedly attached to the sensor rod; and a waveguide tube attached to the cover. The bore of the sensor rode is configured to receive the waveguide tube.

Abstract: A method for detecting complete or partial plugging of a measuring tube of a Coriolis flow measuring device, which is insertable into a pipeline, and which has a measuring transducer of the vibration type having at least two measuring tubes connected for parallel flow. The method includes, in such case, the steps of measuring a subset flow occurring in a subset of the measuring tubes, and comparing a subset flow value obtained from this measurement with a reference value to be expected for this subset. The reference value is, in such case, determined from a total mass flow determined in the context of a Coriolis mass flow measuring. Additionally, the method includes the step of detecting plugging of at least one measuring tube of the measuring transducer, if the subset flow value deviates from the reference value by more than a limit value.

Abstract: Disclosed is a pulley of a motor configured to accurately collect data for performance test without damaging screw threads of the pulley and a test jig, wherein the motor includes a rotation shaft and the pulley coupled to a distal end of a rotation shaft, and wherein the pulley includes a jig coupling groove axially formed at a distal end in the shape of a plurality of holes, and a part of a performance test jig is axially inserted, and the test jig of the motor, the test jig connected to the pulley coupled to a distal end of the rotation shaft of the motor to measure performance test, the test jig comprising a coupling pin lengthily and axially formed at the other distal end coupled to the pulley of the test jig, and inserted into a hole formed at the pulley.

Abstract: A torque and index detection apparatus includes a torque sensing section that senses torque exerted on a connecting shaft connecting a first and second shafts by a pair of magnetic sensing elements whose magnetic sensing directions are opposite, and a reference rotational position sensing section that senses a reference rotational position of the second shaft by the magnetic sensing elements. The reference rotational position sensing section includes a pair of magnets provided in the circumferential direction of the second shaft with like magnetic poles facing each other, a first magnetic part that is located between the magnets and the magnetic sensing elements, rotates integrally with the second shaft, and forms a magnetic path for magnetic flux of the magnets in the reference rotational position, and a second magnetic part that is provided between the magnetic sensing elements, and passes the magnetic flux from the first magnetic part uniformly to the magnetic sensing elements.

Abstract: A device for monitoring belt tension includes two supporting elements for supporting a belt, a deflecting element between the supporting elements, at least one elastic element and a switch. A sufficiently high tension for a belt that is supported on the supporting elements and guided past the deflecting element may be displayed if the deflecting element has been moved in a predefined way against a restoring force of the elastic element, thereby actuating the switch.

Abstract: Methods of sampling substances such as subsurface contaminants, a transfer line for use in a system for such sampling, a sampling system and methods of manufacture and use of the system are described. The transfer line used in a probe system for subsurface chemical sampling connects a detection apparatus with a probe, the transfer line including a first flexible tube for carrying fluid to the probe; and a second flexible tube for carrying sample-loaded fluid from the probe; wherein second flexible or both first and second flexible tubes comprise a barrier tube surrounded by a metal coating. The metal coating is a continuous cladding deposited with structural integrity, and the metal coating is surrounded by an insulating layer, so that one or both of the flexible tubes can be heated by applying a voltage on the metal coating.

Abstract: A two-lip dust-proof wiper of a ball screw having a main ring body, with a ringed sheet, and a screwed hole, a circumferential portion and first/second flanged portions. A wiping ring surface is set into the hole. Fine interference fit can be implemented between the wiping ring surface and the periphery of the ball screw. A first wiping lip is annularly formed onto the wiping ring surface for mating with the first flanged portion, and a second wiping lip is annularly formed onto the wiping ring surface for mating with the second flanged portion, such that the first/second wiping lips are protruded at both sides of the surface. The wiping lips and the periphery of ball screw are under interference fit, the interference being larger than that of the wiping ring surface and ball screw. The protruding direction of the wiping lips runs parallel with the flanged portions.

Abstract: A synchronizing device of a transmission is provided with a cylindrical synchronizer body having an external toothing. A shifting sleeve includes, but is not limited to an internal toothing. The internal toothing axially displaceably meshes with the external tooting of the synchronizer body. A synchronizing ring includes, but is not limited to a locking gear rim. In clearances distributed on the circumference of the synchronizer body, pre-synchronizing elements are arranged. The pre-synchronizing elements are in spring-elastic engagement with the shifting sleeve and are arrested by the shifting sleeve in a middle position. A face end of the locking gear rim includes, but is not limited to outward bulges in direction of the pre-synchronizing elements subject to the setting of spacing between synchronizing ring and pre-synchronizing elements.

Abstract: A drive transmitter, including a first rotational axis transmitting a drive force of a drive source to a first rotator, a second rotational axis transmitting a drive force of the drive source to a second rotator, and an idler gear configured to transmit a drive force to the second rotational axis; wherein the first rotational axis penetrates the idler gear with a gap therebetween.

Abstract: A retainer made of a synthetic resin for use in a deep groove ball bearing is proposed of which the lubricity has been improved. The retainer includes a cylindrical first split retainer member (41) having a first axial side, and a cylindrical second split retainer member (42) having a second axial side coupled to the first axial side of the first split retainer member (41). Circumferentially spaced apart first and second cutouts (45 and 50) are formed in the first axial side of the first split retainer member (41) and the second axial side of the second split retainer member (42), respectively, which define respective pockets for receiving balls with the split retainers (41 and 42) coupled together.

Abstract: A modular shift device for an automatic transmission having a first module adapted for pushbutton operation of the transmission's safety lockout, and a second module that when coupled to the first module, modifies operation of the transmission's safety lockout to that of shift shaft tilting and eliminates the pushbutton.

Abstract: A load transmitting connector 13 for composite tube 11 and a method of attachment of said connector 13 to the tube 11, the connector 13 comprising a screw threaded nut 14 having an outer surface 18 shaped to receive the composite, an annular collar 15, a screw threaded end fitting 16 for engaging the screw thread within the nut 14 , and a load means 17, wherein the nut 14 is incorporated within said one end of the tube during tube manufacture, the tube 11 being cured with the nut 14 in situ, the annular collar 15 is placed over said one end of the tube, the end fitting 16 is screwed into the nut, and the load means 17 in use axially moving the end-fitting 16 relative to the collar 15 to exert a clamping load on the composite tube.

Abstract: A parallel robot includes a movable-section drive mechanism, and a wrist-section drive mechanism. The wrist section includes a first rotary member supported on the movable section and rotatable about a fourth rotation axis different from axes of the three-axis translational motion of the movable section, a second rotary member connected to the first rotary member and rotatable about a fifth rotation axis orthogonal to the fourth rotation axis, and a third rotary member connected to the second rotary member and rotatable about a sixth rotation axis orthogonal to the fifth rotation axis. The third rotary member is provided with an attachment surface to which a tool is attached. The attachment surface is inclined with respect to the sixth rotation axis at a predetermined angle.

Abstract: A limiting portion of a support member, which rotatably supports an accelerator pedal, forms a gap between a contacting portion of the accelerator pedal and the limiting portion in a state where the accelerator pedal is rotated in a depressing direction. A cover member is provided to one of the support member and the accelerator pedal and covers the gap at any rotational position of the accelerator pedal within a rotatable range of the accelerator pedal.

Abstract: A stopper disposed for preventing a folded folding bike from moving is disclosed. The stopper includes an insert on a fork and a socket on a chain stay. The insert and socket are provided with a tapered end and a locking recess, respectively. When a folding bike is folded, it can be locked by inserting the tapered end into the locking recess.

Abstract: A control handle knob assembly for use with a control handle of a ZTR vehicle. The knob assembly includes a control handle engagement portion having a clamping mechanism configured to fixedly engage the control handle of the ZTR vehicle. The assembly includes an extension portion having a support rod attached to the control handle engagement portion and a user interface portion having a rotating knob attached to the support rod at an end opposite control handle engagement portion. The knob is attached to allow free rotation of the knob about the support rod.

Abstract: A bicycle pedal comprises a pedal body (10) with a foot support surface (12), a pedal axle (16) holding the pedal body (10) for rotation thereon, a bearing element arranged between the pedal axle (16) and the pedal body (10), a fixing element (20) preferably fully surrounding the pedal axle (16), with the fixing element (20) being provided for fixing the bearing element in the pedal body (10), and a guide element (22) arranged on an inner side of the pedal for lateral guidance of a foot (38) supported on the foot support surface (12), the guide element (22) at least partially covering the fixing element (20) when seen in plan view.

Abstract: A control pedal assembly includes a pedal bracket, a control pedal, an urging device and a communicating portion. The pedal bracket is secured to a vehicle body and has a housing space. The control pedal is swingably supported by a support shaft disposed in the housing space of the pedal bracket. The urging device is to urge the control pedal toward a rear of a vehicle body. The communicating portion is provided at a rear of the support shaft relative to the vehicle body between the control pedal and the pedal bracket to connect a space above the control pedal and a space below the control pedal.

Abstract: Energy storage devices for storing energy are provided. An energy storage device includes a flywheel disposed in a chamber of a journal. A gas bearing is formed between an outer face of the flywheel and an inner face of the journal. The gas bearing exerts a compressive force on the flywheel, which allows for higher rotational velocities and higher energy storage.

Abstract: A flywheel includes a wheel having a composite rim structure with multiple radial layers of steel material. Epoxy type adhesive can bond the multiple layers of stainless steel together.

Abstract: An energy storage system is generally disclosed. An example system includes a flywheel having a substantially cylindrical flywheel portion, and a housing defining a substantially cylindrical cavity configured so as to receive the substantially cylindrical flywheel portion. The flywheel is rotatable in the cavity about a central axis of the flywheel, and an energy exchange device is configured to convert between electrical energy and kinetic energy associated with rotation of the flywheel. The system may also have a magnetic restraint arranged to exert a magnetic restraining force on the flywheel in a direction towards the central axis.

Abstract: A bicycle pedal comprises a pedal body having a support surface and a pedal axle rotatably supporting the pedal body. The pedal is characterized in that the support surface has a recess extending substantially across the entire width of the pedal, the deepest portion of the recess being offset from the pedal axle.

Abstract: A gear device which has a shaft member including a gear portion and a shaft portion formed consecutively and integrally with the gear portion; and a fitting member that may be fitted into the shaft portion of the shaft member, wherein, in the shaft member, at least the gear portion may be formed by a plastic working, a guard portion protruding from a addendum circle of the gear portion to an outer side in the radial direction may be formed in an end portion of a shaft portion side of an axial direction of the gear portion, and the movement in the axial direction of the fitting member may be restricted by the guard portion.

Abstract: A method for producing multiphase particle-reinforced metal matrix composites is provided. The method is characterized by the combination of an in-situ reaction process under an external electromagnetic field and an in-situ crystallization process under an external electromagnetic field. A traveling wave magnetic field or a rotating magnetic field is employed during the in-situ reaction process, and a rotating magnetic field or a high frequency magnetic field is employed during the in-situ crystallization process. Said method can obtain homogeneous, gradient enhanced or surface reinforced composite materials.

Abstract: The various embodiments herein provide a method of producing silver nanoparticles using an electromagnetic levitation melting process. The method comprises levitating and melting a silver sample using a suitable levitation coil and stabilizing a droplet of molten silver. The silver droplet is heated and levitated simultaneously by an induction furnace as a generator. Argon gas is used to provide the inert atmosphere and also applied to cool and condense the silver vapor into a silver nano powder to obtain a silver nano particle. The synthesized silver nanoparticles are collected by brushing them off the brass cylinder using inert gas and are kept in pure Hexane. The size of the nanoparticles is controlled by rate of cooling and heating temperature. The electromagnetic levitation melting method is applied to provide the high purity of silver nano particles with no vacuum equipments.

Abstract: An object of the present invention is to provide a method for producing molten iron, the method being capable of minimizing the generation of converter dust and increasing the thermal degree of freedom in the converter process. In addition, the present invention provides a method for improving a converter operation method in the production of steels. The present invention relates to a method for producing molten iron including the steps of: 1) supplying carbon-containing molten pig iron to a converter, 2) continuously supplying iron oxide into the converter, and 3) blowing a mixed gas comprising a fuel gas and a combustion-supporting gas at a speed equal to or faster than the speed of sound to the molten pig iron to cause a combustion reaction, thereby heating the molten pig iron by heat of the combustion reaction.