Abstract: For the purpose of solving the above problems, the present invention includes: transmission/reception means provided in a flow path for performing transmission/reception using a state change of fluid; repetition means for repeating the transmission/reception; time measurement means for measuring a time of propagation repeated by the repetition means; flow rate detection means for detecting a flow rate based on a value of the time measurement means; and number-of-times change means for changing to a predetermined number of repetition times. With such a structure, an influence caused by a variation of a flow can be suppressed pressed by changing the number of repetition times so as to be suitable for a variation. As a result, reliable flow rate measurement with a high accuracy can be achieved.

Abstract: For the purpose of solving the above problems, the present invention includes: transmission/reception means provided in a flow path for performing transmission/reception using a state change of fluid; repetition means for repeating the transmission/reception; time measurement means for measuring a time of propagation repeated by the repetition means; flow rate detection means for detecting a flow rate based on a value of the time measurement means; and number-of-times change means for changing to a predetermined number of repetition times. With such a structure, an influence caused by a variation of a flow can be suppressed by changing the number of repetition times so as to be suitable for a variation. As a result, reliable flow rate measurement with a high accuracy can be achieved.

Abstract: An input unit for receiving a signal from an oscillator corresponds to an ultrasonic wave received by the oscillator has an input impedance significantly smaller than an impedance of an inter-electrode capacitance in the oscillator. This arrangement allows the delay of timing of the received wave to be influenced by a change in the input impedance of the input unit than by a change in the impedance of the oscillator. Since the influence of the change in the impedance of the oscillator against the delay of timing of the received wave is reduced, a flow meter can measure a propagation duration of the ultrasonic wave accurately. More specifically, the flow meter can measure the propagation duration accurately regardless of a change of the inter-electrode capacitance of the oscillator by temperature, thus measuring a flow rate of fluid correctly.

Abstract: For the purpose of solving the above problems, the present invention includes: transmission/reception means provided in a flow path for performing transmission/reception using a state change of fluid; repetition means for repeating the transmission/reception; time measurement means for measuring a time of propagation repeated by the repetition means; flow rate detection means for detecting a flow rate based on a value of the time measurement means; and number-of-times change means for changing to a predetermined number of repetition times. With such a structure, an influence caused by a variation of a flow can be suppressed by changing the number of repetition times so as to be suitable for a variation. As a result, reliable flow rate measurement with a high accuracy can be achieved.

Abstract: A heat-resistant plastic tube is mainly made of a polyester-based elastomer and exhibits a change amount in angle of ±10° or less in a shape retainability performance test, a change rate in inner diameter of ±2% or less in a dimensional stability performance test, a change rate in yield strength of ±30% or less in a flexibility retainability performance test. The heat-resistant plastic tube can be subjected to a thermal bending at a temperature in a use environment or higher and exhibits excellent retention of the bent shape through the thermal bending after being left in the use environment.

Abstract: An input unit for receiving a signal from an oscillator corresponds to an ultrasonic wave received by the oscillator has an input impedance significantly smaller than an impedance of an inter-electrode capacitance in the oscillator. This arrangement allows the delay of timing of the received wave to be influenced by a change in the input impedance of the input unit than by a change in the impedance of the oscillator. Since the influence of the change in the impedance of the oscillator against the delay of timing of the received wave is reduced, a flow meter can measure a propagation duration of the ultrasonic wave accurately. More specifically, the flow meter can measure the propagation duration accurately regardless of a change of the inter-electrode capacitance of the oscillator by temperature, thus measuring a flow rate of fluid correctly.

Abstract: A flow rate measurement apparatus includes: a plurality of flow paths 13 provided between an inflow port 11 and an outflow port 12; opening/closing sections 14 for opening/closing the plurality of flow paths 13; measurement sections 15 for measuring a flow rate of fluid flowing through at least one of the plurality of flow paths 13; and a control section 17 for controlling the opening/closing sections 14 and the measurement sections 15; The control section 17 includes a gain adjustment section 16 for correcting a gain of the measurement section 15 in a flow path which is closed by the opening/closing section 14.

Abstract: A tube for fuel transportation according to the present invention includes an innermost layer comprising one selected from the group consisting of fluorine type resins and polyamide type resins, a middle layer comprising a polyalkylene naphthalate resin, an outer layer comprising a thermoplastic resin or a thermoplastic elastomer, and an adhesive layer formed between the innermost layer and the middle layer. Polybutylene naphthalate may be used as the polyalkylene naphthalate resin. The tube for fuel transportation according to the present invention has excellent barrier action against fuels and is highly kink-proof.

Abstract: An ultrasonic flowmeter includes a flow path defined by four wall sections, a flow measurement section, a calculation section and a pair of ultrasonic oscillators for transmitting and receiving an ultrasonic wave over a distance. The flow path is configured to reduce the influence of a phase difference, which results from the varying propagation distances of a direct wave and a reflected wave, by changing one or more of the flow measurement section configuration, the ultrasonic wave frequency, the orientation of the ultrasonic oscillators, and the distance between the pair of ultrasonic oscillators. A measurement section is suitably configured to measure the propagation time of the ultrasonic wave propagating between the pair of ultrasonic oscillators. Additionally, a calculation section is suitably configured to receive measurements from the measurement section and to calculate the fluid flow in the flow measurement section.

Abstract: A tube for fuel transportation according to the present invention includes an innermost layer comprising one selected from the group consisting of fluorine type resins and polyamide type resins, a middle layer comprising a polyalkylene naphthalate resin, an outer layer comprising a thermoplastic resin or a thermoplastic elastomer, and an adhesive layer formed between the innermost layer and the middle layer. Polybutylene naphthalate may be used as the polyalkylene naphthalate resin. The tube for fuel transportation according to the present invention has excellent barrier action against fuels and is highly kink-proof.

Abstract: A fuel transfer tube comprises an inner layer of hot-melt fluororesin and an outer layer of partial aromatic polyamide resin or ethylene-vinyl alcohol copolymer. The layer of hot-melt fluororesin reliably prevents alcohol from permeating into the tube, while gasoline is effectively prevented from permeating into the tube by the layer of partial aromatic polyamide resin or ethylene-vinyl alcohol copolymer. The fuel transfer tube, therefore, is suitable for transferring alcohol, gasoline and a mixture thereof.

Abstract: A DC power source constituted by a power generator (20), a dynamo (22) and a rectification means (23), an inverter power source (24) which boosts an output of the DC power source so as to drive a magnetron (28) and an inverter controller for controlling the inverter power source (24) by an output of a generated electric power output detecting means (31) for detecting the output of the DC power source are provided, whereby a required dielectric heating function can be stably achieved by controlling an operational state of the inverter power source (24) by the output of the DC power source.

Abstract: A high-frequency heating device includes a power converter for converting an electric power from a commercial power source or the like into a high-frequency power, a step-up transformer having a high-voltage winding and a low-voltage winding, a magnetron receiving high-voltage and low-voltage outputs, a resonance circuit connected in series or parallel with the filament of the magnetron, and a control circuit. The control circuit controls the power converter so that the operation frequency of the power converter approximately coincides with the resonance frequency of the resonance circuit at the time of activating the power converter to thereby achieve a rapid start of the oscillation operation of the magnetron while suppressing a high voltage from taking place at the activation time to prevent the possible occurrence of the moding phenomenon.

Abstract: A high frequency heating arrangement includes a power converting unit with one or more semiconductor devices which dissipates a slight heat loss. A magnetron receives an output from the power converting unit and supplies electromagnetic waves to a heating chamber. The magnetron dissipates a heat loss that is relatively larger than that of the power converting unit. A cooling fan has a motor which dissipates a heat loss which is relatively smaller than that of the power converting unit. The cooling fan is for cooling the power converting unit and the magnetron. A case is provided in which at least the power converting unit and the magnetron are housed and which is made of an electricity-conductive material. A cooling air passage, along which the motor and the case are arranged, and through which air flows from said cooling fan is provided. Air sent from the cooling fan first cools the motor, then cools at least a portion of the power converting unit, and finally cools the magnetron.

Abstract: A high frequency heating apparatus includes a unitary structure including a magnetron for generating a microwaves, an inverter power supply for supplying a high voltage electric power to the magnetron, and a cooling unit for cooling the magnetron and the inverter power supply, all of which are accommodated within a common metallic casing. The unitary structure is provided at least one of a detector for detecting an operating condition of the cooling unit and a safety device including a detector for detecting a mounting of the metallic casing to a cabinet. For avoiding an electric shock, the unitary structure is divided into high and low voltage portions and the magnetron and the inverter power supply are electrically connected directly to each other without relying on the unitary structure so as to thereby accomplish a structure effective to minimize noise and to improve the reliability and the safety factor.

Abstract: An electric cooking apparatus includes a single power converter section for converting power supplied from an external AC power source. A heating-energy radiator section receives the converted power from the power converter section and radiates heating energy to a heating chamber. A battery is also provided for supplying power to the power converter section such that a sum of the power from the external AC power source and the battery is converted by the power converting section when an instantaneous voltage of the external AC power source is smaller than a predetermined voltage level, which predetermined voltage level is smaller than a maximum instantaneous voltage of the external AC power source.