Abstract: A device for providing a gas and temperature compensated acoustic measurement of the level of a liquid surface, including a transmitter, a receiver, and a waveguide for guiding acoustic signals. The waveguide includes a reference portion extending from a first end to a reference element, and a measurement portion extending from the reference element towards the end. The device further includes a channel extending from at least one inlet in said reference portion to at least one outlet in said measurement portion, the channel being separated from the waveguide so as to provide a fluid flow independent of the waveguide, and a gas-pump arranged to create a gas flow in said channel from said at least one inlet to said at least one outlet.

Abstract: A device for providing a gas and temperature compensated acoustic measurement of the level of a liquid surface, including a transmitter, a receiver, and a waveguide for guiding acoustic signals. The waveguide includes a reference portion extending from a first end to a reference element, and a measurement portion extending from the reference element towards the end. The device further includes a channel extending from at least one inlet in said reference portion to at least one outlet in said measurement portion, the channel being separated from the waveguide so as to provide a fluid flow independent of the waveguide, and a gas-pump arranged to create a gas flow in said channel from said at least one inlet to said at least one outlet.

Abstract: The present device provides for a gas composition and temperature compensated acoustic measurement of the level of a liquid in a tank. The device comprises a transmitter, a receiver, a processing circuitry, a waveguide for guiding acoustic signals from the transmitter to the liquid level surface and for guiding reflections of the acoustic signals back to the receiver. The waveguide comprises a first end connected to the transmitter, a second end adapted to extend into the liquid, at least one inlet for introducing gas originating from the liquid in the tank into the waveguide, and an outlet for discharging gas out from the waveguide into the tank. The outlet is arranged closer to the first end than at least one of said at least one inlet.

Abstract: The present device provides for a gas composition and temperature compensated acoustic measurement of the level of a liquid in a tank. The device comprises a transmitter, a receiver, a processing circuitry, a waveguide for guiding acoustic signals from the transmitter to the liquid level surface and for guiding reflections of the acoustic signals back to the receiver. The waveguide comprises a first end connected to the transmitter, a second end adapted to extend into the liquid, at least one inlet for introducing gas originating from the liquid in the tank into the waveguide, and an outlet for discharging gas out from the waveguide into the tank. The outlet is arranged closer to the first end than at least one of said at least one inlet.

Abstract: A method for determining the starting instant (t0) of a periodically oscillating signal response (E2; E2?), wherein the signal response comprises a first set of half periods (E2a-d; E2?a-d) having a polarity equal to a polarity of the first half period (E2a; E2?a) in the signal response, and a second set of half periods (E2e-h; E2?e-h) having a polarity opposite to the polarity of the first half period (E2a; E2?a) in the signal response. The method comprises the steps of: determining a peak half period (E2e; E2?f) as the half period with the highest amplitude in a selected one of the first and second sets; determining a zero-crossing instant (ZC1; ZC?1) of the signal response occurring a known time distance from the peak half period (E2e; E2?f); determining the starting instant (t0) of the signal response (E2; E2?) based on the zero-crossing instant (ZC1; ZC?1) and a relationship between the peak half period (E2e; E2?f) and the starting instant (t0).

Abstract: A wear pad of a band saw guide exposed to wear from a moving band saw blade is produced in a powder metallurgical manner from a steel material having the following composition, in percent by weight: 0.01-2 C, 0.01-3.0 Si, 0.01-10.0 Mn, 16-33 Cr, max. 5 Ni, 0.01-5.0 (W+Mo/2), max. 9 Co, max. 0.5 S, 1.6-9.8 N, 7.5 to 14 of (V+Nb/2), wherein the contents of N and of (V+Nb/2) are balanced in relation to each other so that the contents of the elements are within a range I?, F?, G, H, I? in a coordinate system, where the content of N is the abscissa and the content of (V+Nb/2) is the ordinate, and where the coordinates for the points (in the format [x: (N, (V+Nb/2)]) are [I?: (1.6, 7.5)], [F?: (5.8, 7.5)], [G: (9.8, 14.0)], and [H: (2.6, 14.0)], max 7 of any of Ti, Zr, and Al; and a balance essentially only iron and unavoidable impurities.

Abstract: At least one embodiment of the present invention relates to a device for providing a compensated measurement of the level of a liquid in a tank. In at least one embodiment, the device includes a transducer adapted to transmit and receive acoustic signals; a waveguide connected to the transducer and adapted to extend into the liquid; at least one collecting device for collecting free-moving portions of said liquid; and at least one directing device for directing fluid originating from liquid collected by the collecting device into or along a portion of the waveguide which during operation is located above the liquid level. At least one embodiment of the present invention also relates to a corresponding method.

Abstract: The present invention relates to a transducer device (10), comprising: an acoustic membrane (14); a piezoelectric element (12) mounted to the acoustic membrane; two oppositely arranged elastic damping elements (16a, 16b) between which a peripheral portion (22) of the acoustic membrane is sandwichably supported; and a clamp (28) having two surfaces (30a, 30b) between which the two elastic damping elements are clamped so that the two elastic damping elements are pressed together, whereby the peripheral portion of the acoustic membrane is secured between the two elastic damping elements. The present invention also relates to a method of assembling such a transducer device.

Abstract: The present invention relates to a device (10) for providing a temperature compensated measurement of the level of a liquid (14) in a tank (12; 30). The device comprises a transducer (22) for transmitting and receiving acoustic signals, and a waveguide (24) connected to the transducer and adapted to extend into the liquid. The device is characterized by means (16; 18; 40) for directing a flow of liquid originating from the tank of along the exterior of a portion of the waveguide which during operation is located above the liquid level. The present invention also relates to a corresponding method for providing a temperature compensated measurement of the level of a liquid in a tank.

Abstract: A device is disclosed for providing a temperature compensated measurement of the level of a liquid in a tank. The device includes a transducer for transmitting and receiving acoustic signals, a waveguide connected to the transducer and adapted to extend into the liquid, and at least one device for directing a flow of heat transfer fluid originating from a heat transfer system along the exterior of a portion of the waveguide which during operation is located above the liquid level. Further, a device is disclosed for controlling a heat regulating device adapted to regulate a temperature of a liquid in a tank, including a transducer for transmitting and receiving acoustic signals, a waveguide connected to the transducer, the waveguide having a reference portion located above the liquid surface, and a control device configured to measure the speed of sound in the reference portion as an indication of a temperature in the liquid, and control the heat regulating device based on the indicated temperature.

Abstract: A method for determining the starting instant (t0) of a periodically oscillating signal response (E2; E2?), wherein the signal response comprises a first set of half periods (E2a-d; E2?a-d) having a polarity equal to a polarity of the first half period (E2a; E2?a) in the signal response, and a second set of half periods (E2e-h; E2?e-h) having a polarity opposite to the polarity of the first half period (E2a; E2?a) in the signal response. The method comprises the steps of: determining a peak half period (E2e; E2?f) as the half period with the highest amplitude in a selected one of the first and second sets; determining a zero-crossing instant (ZC1; ZC?1) of the signal response occurring a known time distance from the peak half period (E2e; E2?f); determining the starting instant (t0) of the signal response (E2; E2?) based on the zero-crossing instant (ZC1; ZC?1) and a relationship between the peak half period (E2e; E2?f) and the starting instant (t0).

Abstract: The present invention relates to a device (10) for providing a gas composition compensated acoustic measurement of the level of a liquid (16) in a tank (18). The device comprises a transducer (14) arranged outside said liquid for transmitting and receiving acoustic signals, and a waveguide (12) connected to said transducer and extending into the liquid. The device further comprises means for feeding a flow of fluid from said tank into the part of said waveguide which is located above the liquid level. That results in that the gas composition become essentially similar throughout the whole of the waveguide located above the liquid level, whereby the level measurement using the speed of sound in the waveguide, which speed is dependant on gas composition, becomes very accurate.

Abstract: At least one embodiment of the present invention relates to a device for providing a compensated measurement of the level of a liquid in a tank. In at least one embodiment, the device includes a transducer adapted to transmit and receive acoustic signals; a waveguide connected to the transducer and adapted to extend into the liquid; at least one collecting device for collecting free-moving portions of said liquid; and at least one directing device for directing fluid originating from liquid collected by the collecting device into or along a portion of the waveguide which during operation is located above the liquid level. At least one embodiment of the present invention also relates to a corresponding method.

Abstract: The present invention relates to a transducer device (10), comprising: an acoustic membrane (14); a piezoelectric element (12) mounted to the acoustic membrane; two oppositely arranged elastic damping elements (16a, 16h) between which a peripheral portion (22) of the acoustic membrane is sandwichably supported; and a clamp (28) having two surfaces (30a, 30b) between which the two elastic damping elements are clamped so that the two elastic damping elements are pressed together, whereby the peripheral portion of the acoustic membrane is secured between the two elastic damping elements. The present invention also relates to a method of assembling such a transducer device.

Abstract: The present invention relates to a device (10) for providing a temperature compensated measurement of the level of a liquid (14) in a tank (12; 30). The device comprises a transducer (22) for transmitting and receiving acoustic signals, and a waveguide (24) connected to the transducer and adapted to extend into the liquid. The device is characterized by means (16; 18; 40) for directing a flow of liquid originating from the tank of along the exterior of a portion of the waveguide which during operation is located above the liquid level. The present invention also relates to a corresponding method for providing a temperature compensated measurement of the level of a liquid in a tank.

Abstract: The present invention relates to a device (10) for providing a gas composition compensated acoustic measurement of the level of a liquid (16) in a tank (18). The device comprises a transducer (14) arranged outside said liquid for transmitting and receiving acoustic signals, and a waveguide (12) connected to said transducer and extending into the liquid. The device further comprises means for feeding a flow of fluid from said tank into the part of said waveguide which is located above the liquid level. That results in that the gas composition become essentially similar throughout the whole of the waveguide located above the liquid level, whereby the level measurement using the speed of sound in the waveguide, which speed is dependant on gas composition, becomes very accurate.

Abstract: The present invention relates to a device (10) for providing a gas composition compensated acoustic measurement of the level of a liquid (16) in a tank (18). The device comprises a transducer (14) arranged outside said liquid for transmitting and receiving acoustic signals, and a waveguide (12) connected to said transducer and extending into the liquid. The device further comprises means for feeding a flow of fluid from said tank into the part of said waveguide which is located above the liquid level. That results in that the gas composition become essentially similar throughout the whole of the waveguide located above the liquid level, whereby the level measurement using the speed of sound in the waveguide, which speed is dependant on gas composition, becomes very accurate.

Abstract: The present invention relates to a device (10) for providing a gas composition compensated acoustic measurement of the level of a liquid (16) in a tank (18). The device comprises a transducer (14) arranged outside said liquid for transmitting and receiving acoustic signals, and a waveguide (12) connected to said transducer and extending into the liquid. The device further comprises means for feeding a flow of fluid from said tank into the part of said waveguide which is located above the liquid level. That results in that the gas composition become essentially similar throughout the whole of the waveguide located above the liquid level, whereby the level measurement using the speed of sound in the waveguide, which speed is dependant on gas composition, becomes very accurate.

Abstract: Method in a multi-tone transmission system wherein a usable frequency range of a channel is separated into a plurality of frequency bands, an analogue signal in each sub band being filtered out by a plurality of band pass filters at a receiving side. The method comprises the steps of converting separately the analogue signal in each sub band into a digital signal in a plurality of Analogue-Digital converters (11), each Analogue-Digital converter being associated to one sub band, and activating and deactivating each Analogue-Digital converter in dependence of the presence of a signal in the associated sub band. A plurality of bandpass filters (10) is operatively connected to an analogue line (12) at a receiving side. Each bandpass filter is operatively connected to an Analogue-Digital converter (11) for converting an analogue signal into a digital signal. A control unit (13) is operatively connected to each of said Analogue-Digital converters (11) for activating and deactivating each converter.