Contraves Ag

Markus Feier

Ulrich Marti

Raymond Frey

Georg Zemp

Donald P Stait

Andre Ruegg

A dosing and mixing apparatus for fluid media comprising at least one delivery element and one isolating element. These elements are provided with through-flow or transfer passages and dosing chambers suitably mutually arranged for accomodating and isolating a voluminized specimen quantity or measured dose of test specimen as well as for delivering this measured out dose of test specimen to and mixing this dose of test specimen with a measured dose of thinning agent. The dosing and mixing apparatus manifests itself in that at least one channel suitably associated with the dosing chamber is provided in a surface of one of the elements, such as the isolating element at the surface thereof which faces the delivery element. Each such channel communicates with through-flow openings or circulation passages and is traversed by a cleansing fluid wetting the mutually facing and touching surfaces of the individual delivery and isolating elements in the transport path of the dose of test specimen.

Dosing and mixing apparatus for fluid media

The viscometer comprises a measuring element suspended on a torsion wire and immersed in a substance to be tested contained in a measurement vessel. The measurement vessel with the therein contained substance is driven by a first drive member. A second drive member as well as a measuring system are arranged on a shaft between the torsion wire and the measuring element. A signal transducer prescribes or sets a predetermined amount of torque for the second drive member. The predetermined amount of torque corresponds to a predetermined shear stress characteristic of the substance to be measured. A predetermined angular deflection or angular velocity is applied to the first drive member through a regulation connection arranged between the measuring system and the first drive member. The viscometer is, due to its high accuracy, particularly advantageous for applications in low viscosity ranges of structurally viscous substances.

Method of and apparatus for measuring rheological characteristics of

During a predetermined measuring time there are generated electrical pulses in a detector arrangement, each of these electrical pulses corresponding to a respective particle which is to be counted. The pulse amplitude of the electrical pulses corresponds to the particle size. In a discriminator circuit the electrical pulses are compared with a threshold value. Those pulses, the pulse amplitude of which exceeds the threshold value, are inputted to a counter circuit and a time measuring circuit for measuring the total time duration of the electrical pulses. All of the electrical pulses are delivered to a further counter circuit and a time measuring circuit. The digital values derived from both counter circuits and both time measuring circuits are infed to a digital computer in which there is computed according to the equation Z.sub.T *=(Z.sub.S -Z.sub.E).multidot.T.sub.S /(T.sub.S -T.sub.E) a count result Z.sub.T * for the pulses, the pulse amplitude of which does not exceed the threshold value. This count result Z.sub.T * has been corrected by the cross-coincidence error.

Method and apparatus for correcting coincidence errors during counting

An auxiliary apparatus for a particle analyzer for measuring the particle count within particle size intervals bounded by shiftable or displaceable thresholds. Infeed lines conduct the signals generated in a feeler to comparators. Other infeed lines conduct the comparison voltages generated by comparison voltage generators to the same comparators, an operating element simultaneously alters the comparison voltages from two comparison voltage generators by the same magnitude and a selector switch connects one of two infeed lines with one of the infeed lines. The inputs of an antivalence or Exclusive-Or discriminator are connected by an infeed line or conductor with a time-delay element and by an infeed line or conductor with one comparator, the output of which discriminator is connected by a line or conductor with a pulse counter.

Auxiliary apparatus for a particle analyser

A method of, and apparatus for analyzing particles suspended in a liquid, especially blood cells wherein two vessels or receivers for the liquid containing the suspended particles therein are separated by an electrically insulating wall and an elongate channel penetrates through such wall. Two supply electrodes each respectively connected with one terminal of an electrical power supply contact the liquid in a respective one of the vessels. There is provided at least one auxiliary electrode contacting the liquid in the channel, and the dimensions of each such auxiliary electrode, in a direction parallel to the lengthwise direction of the channel, is small in relation to the length of the channel. There also are provided a number of feeler or sensor means, a respective one of which is operatively associated with a respective pair of the electrodes for detecting the changes, as a function of time, of the potential difference between these electrodes. There is formed an auxiliary value correlated to the timewise course of the potential difference between a given one of the auxiliary electrodes and one of the other electrodes and there is formed a measuring value correlated to the time-wise course of the potential difference between two of the other electrodes. There is triggered sampling of the measuring value for obtaining a sampling value as a function of auxiliary value and corresponding to a particle.

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Otelfingen, Switzerland

Markus Feier