An apparatus is disclosed for measuring instantaneous rate of flow and total flow of a fluid. The data are obtained by measuring the quantity of energy necessary to replace an equivalent amount of heat dissipated from a temperature-sensitive transducer disposed in the path of the fluid flow. An error signal, resulting from a transducer impedence change due to a differential temperature, induced by fluid flow, is placed in digital form and fed back to the transducer in a closed feedback loop configuration. The feedback signal is in the form of discrete power pluses. The number of such pulses is proportional to the heat removed from the transducer by the flow and thus is proportional to the fluid flow rate. The output pulses are counted and displayed in associated digital equipment.

Digital thermodynamic flow-meter

A stable isothermal calorimeter wherein the material under study is contained in a thermally conductive reactor vessel which is surrounded by a heat transfer fluid. The material is maintained at the boiling point of the heat transfer fluid which is in turn cntrolled by controlling the pressure of the fluid's vapor space. The heat transfer fluid is vaporized by the heat released by exothermal reaction of the material under study and the vaporized fluid condensed in a condenser. The rate of liquid accumulation in the condenser is proportional to the energy release rate of the material.

Stable isothermal calorimeter

Probe (1) to be used in a microcalorimeter for various types of heat measurements. The probe having a good thermal contact with thermodetectors (5,6) used in the calorimeter. The probe is designed as a substantially cylindrical hollow body has at least one outer surface (4, 11) which is in contact with the thermodetectors. The outer surface of the probe is provided with a helix groove (2) in which a tube (3) for supplying the continuous flows is arranged in good thermal contact with the probe. The cavity (10) of the body is used for the introduction of the ampoules (9).

Probe for use in a microcalorimeter

A method and apparatus for measuring an unknown quantity of heat in a measuring zone formed by a vessel of good thermal conducting properties is carried out in such a manner that the measuring zone is supplied with a known quantity of heat and the quantity of heat of the measuring zone is given off to a cold zone, that the temperature of the measuring zone is always kept equal to the temperature of the environment and at the same time the dissipation of heat is kept constant by keeping the difference between the temperature of the measuring zone and the temperature of the cold zone always the same, and that the known quantity of heat supplied to the measuring zone is measured at a point outside of the vessel when the unknown quantity of heat is absent and when it is present, the difference between the known quantity of heat in the absence of the unknown quantity of heat on the one hand and the known quantity of heat in the presence of the unknown quantity of heat on the other hand being the measurement result for the unknown quantity of heat. The vessel includes a known heat source and a cold source is provided which is connected with the vessel by way of a heat-conducting element.

Method of and apparatus for the measuring of quantities of heat

A method of determining the proportion of the surface area of a coated substrate that is covered by the coating comprising passing a known volume of an adsorbate gas under controlled flow conditions over a coated substrate and measuring the volume of adsorbate gas adsorbed on the surface area at different temperatures between the liquefaction temperature of the adsorbate gas and ambient temperature; similarly measuring the volume of the adsorbate gas adsorbed on the surface area of the substrate in the absence of the coating in the same temperature range; similarly measuring the volume of the adsorbate gas adsorbed on said coating in the absence of said substrate in the same temperature range; comparing the above volumes at identical temperatures and calculating therefrom the proportion of surface area of said substrate covered by said coating; and an apparatus for practicing said method. This method in this apparatus is especially useful in measuring the surface area of catalytic material on a supported catalyst.

Method and apparatus for determining relative surface areas of a coated material on a substrate

A reaction vessel for isothermal calorimetry, in which the container for the sample consists of two snugly fitting hollow cylindrical bodies, between which there are one or more recesses for the accommodation of the sample.

Reaction vessel for isothermal calorimetry

Method and apparatus for isothermal calorimetry in which the temperature within the calorimeter is maintained at a constant value by the application of energy in the form of pulses of constant power, which pulses are counted and summated, the number of pulses per unit time being determined by temperature control means.

Riedel O

Papers

Reaction vessel for isothermal calorimetry

Isothermal calorimetry method and apparatus therefor

Verfahren und anordnung zur isothermen kalorimetrie