Abstract: The invention provides a photometric method of determining courses of reaction in a specimen, in which method the intensities of the transmitted light and of the stray light are measured, wherein the two intensities are measured simultaneously and the electrical signals corresponding to the transmitted light and to the stray light are combined to form one signal. The invention makes it possible to perform reliable measurement even with low levels of transmitted and stray light.The method is preferably used in determining the coagulation times of blood. Apparatus for carrying out the method is also disclosed.

Abstract: A method for monitoring the exposure of an individual person to toxic gases is carried out such that the gas concentration is continuously measured with a sensor for the specific gas, recorded and the measured values then read and evaluated. Instantaneous values of the concentration are periodically scanned, temporal mean values of the instanteous values are formed over a predetermined time interval, these mean values are stored and an alarm triggered if the instantaneous value and/or the mean value exceeds a predetermined critical value over the time interval or an integral multiple thereof.

Abstract: In an apparatus for process analysis, a test substance is removed from the process stream by a probe and fed to an analysis instrument with a measured value display. Upstream of the analysis instrument, the test gas is conveyed through condensers. A monitoring unit is coupled to the analysis instruments and the processing chain without influencing the flow of data from the analysis instrument to the measured value display. The monitoring unit receives information about the entire apparatus via status sensors which are incorporated into the processing chain and into the analysis instrument. Depending on this information, the monitoring unit can intervene via solenoid valves, switches and motor potentiometers into the apparatus and alter its operation. The condition of the apparatus can also be displayed.

Abstract: A device for reading the results of centrifugal separation of test samples such as samples of blood. The centrifugal separation apparatus is provided with a housing having a hinged cover having a magnifying lens built into it, either as a lens shaped portion of a plastic cover, or as a separate glass lens attached to the cover. Arms on the hinged cover, engaging with abutment portions on a stationary part of the housing, define a position of the cover which is most appropriate for reading the results.

Abstract: A device for reading the results of centrifugal separation of test samples such as samples of blood. The centrifugal separation apparatus is provided with a housing having a hinged cover having a magnifying lens built into it, either as a lens shaped portion of a plastic cover, or as a separate glass lens attached to the cover. Arms on the hinged cover, engaging with abutment portions on a stationary part of the housing, define a position of the cover which is most appropriate for reading the results.

Abstract: A photometer for measuring the light transparency of a substance. A light beam is provided for illuminating a substance, which light beam passes through the substance and strikes a photoelement and produces a measuring current. The voltage generated from the measuring current is logarithmated by a converter circuit and is supplied to an indicating instrument for indicating a measured value. A zero balance control circuit is provided for controlling the voltage applied to the indicating instrument so that the indicating instrument will return to a value determined by a previous measuring of a calibrated substance. If the transparency of the measured substance is identical to the transparency of the calibrated substance, the indicating device will return to a zero value. A value other than zero will indicate the difference in transparency of the measured substance from the calibrated substance.

Abstract: A zero-balancing arrangement incorporated into a pocket-type apparatus, which pocket-type apparatus is capable of being handled and operated by one hand of the user. The apparatus includes at least one battery to supply energy to a lamp which is used as a light source. A cuvet containing a liquid to be measured is placed into the path of a measuring light beam through an opening in the casing of the apparatus. A wedge-shaped filter is movable in the path of a second light beam by manual operation of a setting wheel. A measuring scale provided on the setting wheel can be inspected through a viewing window and the setting wheel can be adjustable relative to a mark fixedly located on the casing of the light beam paths provided in the apparatus, the first one travels through the liquid in the cuvet to a first photoelectric sensing device and the second light beam path travels unobstructed to a second photoelectric light sensing device.

Abstract: A photometer for measuring the light permeability of a material for testing is made portable for hand-held operation outside a laboratory for measurements such as determining the proportion of hemoglobin in human blood. It includes a battery power supply that energizes a lamp, an opening for receiving a cuvet for a measurement, and a measuring circuit having a light-sensitive element. An indicator instrument in the measuring circuit indicates zero compensation, and a manually movable wedge filter is in the path of the light beam for adjusting the light passing through the cuvet. A manually operable element effects a zero compensation of the measuring circuit before a test is made, and a viewable scale on a setting member carrying the wedge filter directly displays a test result value from adjustment of the wedge filter during measurement of the material.

Abstract: A control device for an exposure factor of a photographic camera, such as the factor of shutter time or speed. A settable scale, settable to various values to control the exposure factor, is graduated logarithmically, and movement of the scale causes relative movement between a wiper or slider and a resistance serving as a potentiometer, the resistance of the potentiometer varying in a linear manner rather than logarithmically. The output of the potentiometer is connected to the input of a logarithmizer, the output of which is connected to a control element for controlling the exposure factor, the control being through an operational amplifier serving as an integrator, and through a threshold switch. An RC member associated with the amplifier is short circuited when the shutter is in its rest or closed position, the short circuit being interrupted at the beginning of the opening movement of the shutter.