Abstract:
This invention relates to absolute pressure sensors with two bonded wafers containing a pressure sensing structure and forming a reference pressure chamber and a buffer chamber. Since the buffer chamber collects molecules, which permeate through a bonding interface between the two wafers, a raise in pressure of the reference chamber can be avoided. The sensor is therefore more resistant to pressure equalisation between the pressure chamber and the pressure of the surroundings, i.e. the sensed pressure and repetitive recalibration of the sensor can be avoided.
Abstract:
In a capillary carrier (1) with an inlet (2) and an outlet (3), a channel (4, 7, 22) is formed and extends between the inlet and the outlet. At least one capillary tube (5, 6) is arranged within the channel, and sealing elements (8, 9, 10, 11), by which the capillary tube is sealingly fixed to the channel, are arranged at least near an inlet portion (13) and an outlet portion (12) of the capillary tube. An area (14) is formed limited by a part of the channel, the sealing elements and the exterior of the capillary tube, which is in connection with the exterior of the carrier through a fluid communication pad (15), whereby a possible fluid leak across the sealing elements will be led to this area, and from there to the exterior of the carrier.
Abstract:
The invention relates to an expansion valve (1) for high-pressure refrigeration systems with a valve seat (5), a valve element (9) cooperating with the valve seat (5), a spring arrangement, which acts upon the valve element (9), and an adjusting device (23) for the spring arrangement. It is endeavoured to provide an expansion valve, which can be driven by a relatively weak drive, also in connection with high pressures. For this purpose, the spring arrangement has at least a first spring (11) and a second spring (12), which act upon the valve element, the first spring (11) defining a operating area and the second spring (12) having a spring force, which can be changed by means of the adjusting device.
Abstract:
A method and a device for detecting flash gas in a vapour-compression refrigeration or heat pump system comprising a compressor, a condenser, an expansion device, and an evaporator interconnected by conduits providing a flow path for a refrigerant, by determining a first rate of heat flow of a heat exchange fluid flow across a heat exchanger of the system and a second rate of heat flow of the refrigerant across the heat exchanger, and using the rates of heat flow for establishing an energy balance from which a parameter for monitoring the refrigerant flow is derived, to thereby provide early detection of flash gas with a minimum number of false alarms.
Abstract:
Electronic ignition circuit for oil burners, for generating temporally spaced sparks. The electronic circuitry comprises circuitry for producing temporally spaced sparks with a spacing not corresponding to a half-period of the AC mains frequency or of a multiple of the AC mains frequency. The circuitry may be used in a method for ignition of an oil burner forming part of an oil burner system, where said oil burner comprises electronic circuitry for producing a first sequence of temporally spaced sparks for ignition of the oil. According to the method, the electronic circuitry is adjusted to subsequently produce a second sequence of temporally spaced sparks if it is detected that the ignition results in acoustic resonance in the oil burner system using said first sequence of temporally spaced sparks.
Abstract:
An infusion system for infusion of medication is hereby disclosed. The infusion device is carried on a person's body, and is adjusted by a personal digital device via radio communication. The personal digital device is a general digital device, like an electronic pocket calendar or a mobile phone, which in addition communicates with the infusion device.
Abstract:
A method is provided for the determination of the concentration of compounds in body tissue and fluids. The method utilizes two compartments containing reference solutions, which are separated from the sample by two different semi-permeable membranes, in a serial manner, whereby a difference in osmotic pressure occurs in the two compartments due to compounds, which can permeate one of the membranes, but not the other. The difference in osmotic pressure reflects the concentration of these compounds. The method is especially suited for analysis of the concentration of glucose in blood or tissue of diabetic patients, where a device is implanted underneath the skin of the patient and where the method is carried out by using the implanted device.
Abstract:
The present invention relates to dielectric actuators or sensors of the kind wherein electrostatic attraction between two electrodes located on an elastomeric body leads to a compression of the body in a first direction and a corresponding extension of the body in a second direction. The dielectric actuator/sensor structure comprises a first sheet of elastomeric material having at least one smooth surface and a second surface and a second sheet of elastomeric material having at least one smooth surface and a second surface. The sheets are laminated together with their second surfaces exposed, and there is provided a first electrode on the second surface of the first sheet and second electrode on the second surface of the second sheet.
Abstract:
The invention concerns a transmitting and receiving circuit for an ultrasonic flowmeter. In such circuits, an ultrasonic transducer is typically used as both transmitter and receiver. This is obtained by using switching means, for example in the form of CMOS switches. However, problems arise with ringings of a transducer when having acted as a transmitter. This unwanted ringing makes the crystal of the transducer act as an additional signal generator, and the signal is coupled via parasitic capacitances in a switching means to the receiving ultrasonic transducer. According to the invention, this problem is solved by connecting one pole of a short circuit switch to the ultrasonic transducer or to the switching means and the other pole of the short circuit switch to ground. Keeping the short circuit switch closed when the switching means is open, and open when the switching means is closed, creates a decoupling path for the unwanted signal. This improves the accuracy of the transmitting and receiving circuit.
Abstract:
In a motor actuator, e.g. a valve actuator, comprising a reversible electrical motor (1), a drive circuit (2) is providing a stop function, when the torque of the motor exceeds a predetermined maximum torque. The drive circuit (2) is constructed as a two-terminal circuit connected in series with the reversible electrical motor (1), and the electrical power is supplied to the series connection with a mainly fixed voltage VCC and a polarity which provides the desired rotational direction of the motor (1). This provides the possibility of having the drive circuit (2) positioned close to the motor (1) and maintaining full torque control and stop function with two wire connections.