Abstract: There is provided an electro-therapeutic device having first and second electrodes or probes for making electrical contact to the body of an individual. The device has voltage supplying means for supplying an alternating output voltage across the electrodes to pass an alternating current through the body of the individual, and the voltage supply means are adapted for controlling the frequency of the output voltage so that the output voltage frequency is automatically changing in time between a low frequency and a high frequency. The voltage supply means may be adapted for controlling the frequency of the output voltage so that the output voltage frequency is changing between a low frequency and a high frequency at regular time intervals.

Abstract: An operating mechanism for turning a butterfly valve axle or similar device has a piston/cylinder unit of which the piston is coupled to the axle and is provided with screw-thread means producing rotation of the axle as the piston is reciprocated in the cylinder. The arrangement of the piston/cylinder unit and coupling means is such that a longitudinally compact mechanism is achieved.

Abstract: Wood can be rendered fire resistant by impregnating the wood with a solution of a monomer, such as a phenol, and a fire-inhibiting salt, drying the wood and thereafter treating the wood with a solution of a second monomer, such as formaldehyde, polymerizable with the first monomer. Heating to dryness causes polymerization of the monomers. The fire resistant properties of wood treated this way are not affected by exposure to moisture. Prior to the first impregnation, after the first impregnation and after treatment with the second monomer the wood being treated is dried to a moisture content below about 4%.