Abstract:
An arrangement for ensuring the stability of the set point for a gas analyzer is disclosed. The set point control circuit utilizes an amplifier which is alternately switched between a reference voltage and a sensor signal to provide a signal to a processor representing the reference signal and the sensor signal. The processor compares the two signals and adjusts the heater associated with the sensor to provide a stable set point for the gas analyzer. The arrangement eliminates the need for precision resistors within the set point control circuit and therefore significantly reduces the cost of the circuitry.
Abstract:
Automatic zeroing apparatus zeroes an infrared gas analyzer automatically upon the occurrence of preselected conditions to indicate zero in the absence of absorption of infrared radiation by a gas mixture being analyzed. The gas analyzer has a sample cell for containing a gas mixture to be analyzed. Infrared radiation directed through the sample cell is detected at a preselected wavelength to produce a detection signal. A signal processor outputs a signal systematically related to the difference between the detection signal and a reference signal. For zeroing the sample cell is filled with gas substantially nonabsorbent of infrared radiation at the respective characteristic wavelength. A comparator produces an error signal when the output signal differs from zero. A gain control automatically controls the signal level of the detection signal to reduce the output signal substantially to zero with the nonabsorbent gas filling the sample cell. The preselected conditions may include the passage of a predetermined time and a temperature drift beyond a predetermined limit.
Abstract:
Disclosed is a diving computer in the form of a circular slide rule for aiding a SCUBA diver in planning one or more dives within a short amount of time, including more than one depth per dive, so that the diver may avoid risking decompression sickness. The computer has two faces, one of which calculates the increase of pressure within body tissues during a dive and the other of which calculates the decrease of this pressure after surfacing. The result of one side's calculation is used as the initial value for the other side's calculation, permitting the diver to track net residual pressure over a series of rapid repeated and/or multiple-level dives, and by so doing, avoid excessive tissue pressures that might cause decompression sickness.
Abstract:
In an anchoring arrangement for releasable anchoring of the legs of a marine tension leg platform in a foundation on the sea floor, the lower ends of the tension legs with an end head (1) are lowered into a cylindrical anchoring casing (4). For anchoring the leg in the foundation, locking elements (7) are provided at the tension leg insertion end of casing (4), on the inside of the cylindrical casing wall, for cooperation with bosses (2) on tension leg head (1). Anchoring casing (4) is, furthermore, on the outside of its cylindrical wall, at the insertion end, provided with further bosses/grooves (10). The latter are intended for cooperation with bosses (14,15) and grooves which are provided on the inside of a cylindrical steel ring (13), which is intended to be integrallly moulded into the foundation on the sea floor. Over the end edges of casing (4) and the cylindrical integral ring (13) a locking ring (16) is provided on a contact face to provide additional fixation of the anchoring.
Abstract:
A gas analyzer is described comprising a sample cell for containing a gas mixture to be analyzed, a source for producing and directing infrared energy through the sample cell, a rotary filter wheel having at least one filter thereon for passing infrared energy limited to a wavelength band within the characteristic absorption band of a predetermined gas and having a dark level region substantially opaque to infrared energy, a drive for supporting and rotating the filter wheel to successively interpose the filter and the dark level region between the source and the sample cell in the path of the infrared energy directed by the source, a detector for detecting infrared energy passing through the sample cell and producing an electrical signal representative thereof, and a signal processor connected to the detector for producing an output indicating the concentration of the predetermined gas in the sample cell by comparing the electrical signals produced by the detector with the filter positioned in the infrared energy path and with the dark level region positioned in the infrared energy path. The dark level region has a substantially fully reflective surface oriented toward the sample cell when positioned in the infrared energy path whereby infrared energy impinging thereon is reflected.