Abstract: A catalytic gas burner, as used e.g. in a mobile space heater, comprises a valve housing divided by at least two poppet valves into three or more cascaded chambers. One chamber communicates with a gas inlet and is normally closed by a first poppet valve which can be opened by a push rod and held open by an electromagnet, the latter being energized under the control of a thermocouple as long as an adjoining ancillary nozzle emits a monitoring flame. This nozzle communicates with another chamber to which gas is admitted in the open state of the first poppet valve and which also feeds the main nozzle head of the burner through a supply conduit including a manually and/or thermally controlled flow regulator. A second poppet valve, fixed to the push rod, is open as long as that rod is depressed against a spring force to give access to a further chamber from which supplemental gas is conveyed through another conduit to the nozzle head during a start-up phase while an igniter is being actuated.

Abstract: A space heater, designed to maintain the temperature of a room between a lower limit T.sub.m and an upper limit T.sub.M, is controlled by a system including a sawtooth-wave generator working by way of a clipping stage into a differential amplifier also receiving a monitoring signal representing the difference between an output voltage of a temperature sensor and a reference voltage. The differential amplifier emits a train of command pulses of temperature-dependent duration which temporarily reduce the mean power of the heater to a fraction of its maximum value, as by periodically interrupting its fuel supply when that heater comprises a gas burner. The heater is cut off for an extended period when the upper range limit T.sub.M is exceeded and is then restarted when the temperature falls beneath the lower limit T.sub.m. In the case of a gas burner of the catalytic type, the cut-in is accompanied by a supply of additional gas to the burner for a limited time.

Abstract: A heterogeneous catalyst, especially for the flameless combustion of hydrocarbons such as methane, propane and butane, and which is especially effective in obtaining maximum conversion of such hydrocarbons and minimum release of alkenes, contains on a catalyst support, conventional flameless combustion catalysts such as platinum sponge, palladium and active metal oxides. According to the invention the catalyser combination also includes the manganese oxide Mn.sub.3 O.sub.4 which itself does not have significant catalyst activity.

Abstract: A catalyst mass for heterogeneous catalytic reactions, especially the flameless burning of hydrocarbons, comprises a support consisting of impurity-free silico-alumina fibers and a catalyzer which consists of at least one element (in elemental form) and at least one other oxide of an element from groups III, VI, VIIIb and VIIIc and the rare-earth elements of the periodic table.

Abstract: Contact mass for heterogeneous catalysis, characterized in that it comprises a support of alumina fibers having a large specific surface and good thermal stability, on which is deposited a catalyst comprising at least one element chosen from metals of crude platinum belonging to group VIII of the periodic table of elements, a gas supply device being provided which allows appropriate distribution of the combustible gas.

Abstract: A catalyst system for a catalytic heater comprises a support of a refractory material upon which is deposited by cocrystallization at least one oxide from a Group VI (B) element and at least one oxide from a Group VII (B) or a Group VIII (4th Period) element in addition to a promoter from the platinum-metal group.