Abstract: A mixture of water and glass beads is ejected to a root of a gear which has been cut to form gear teeth. The glass beads are oriented so as to be ejected to the root, and the glass beads and the water impart compressive stresses to the surface of the root and grind the surface of the root.

Abstract: The concentration of cavities in a formed product formed by superplastic forming is measured based on a propagation velocity of ultrasonic waves in the formed product. An ultrasonic measuring head which oscillates and receives ultrasonic waves is brought into contact with the formed product. A measurement is made of the propagation time required for the ultrasonic waves to be incident from the ultrasonic measuring head on the formed product to return to the ultrasonic measuring head upon reflection from a rear surface of the formed product. The propagation velocity is obtained from the measured propagation time and the thickness of the formed product.

Abstract: A temperature sensor comprises a temperature sensing element (20) in an inverted cup-shaped casing (17+18), the casing (17+18) is held slidable in vertical direction on a rod-shaped supporting member (23) with a spring (27) therebetween to enforce the cup-shaped casing (17+18) upward, thus relatively moving portions of the casing (17+18) and the supporting member (23) is covered under the inverted cup-shaped casing (17+18), preventing undesirable trouble in the sliding due to contamination by overflowed meal.

Abstract: This invention is a water heater wherein a heat source is located outside a hot water storage tank and high temperature hot water can be distributed between the regions of the hot water storage tank above and below the middle thereof, reducing loss of heat through dissipation and preparing high temperature hot water at uniform temperature in a short time upon depletion of the hot water.

Abstract: A method for continuously treating an iron member wherein the iron member is first subjected to furnace-brazing in a controlled gas environment and subsequently to a soft-nitriding treatment by addition of ammonia gas (NH.sub.3) to the controlled gas for the brazing. An apparatus for carrying out the method is also provided, and includes three partitioned chambers for brazing, annealing and soft-nitriding the iron member, each chamber being partitioned by a member such as a stainless steel film curtain at opposite sides thereof. A controlled gas feed system communicates with each of the chambers, and an ammonia gas feed system is connected to the soft-nitriding chamber.

Abstract: A method for continuously treating an iron member wherein the iron member is first subjected to furnace-brazing in a controlled gas environment and subsequently to a soft-nitriding treatment by addition of ammonia gas (NH.sub.3) to the controlled gas for the brazing. An apparatus for carrying out the method is also provided, and includes three partitioned chambers for brazing, annealing and soft-nitriding the iron member, each chamber being partitioned by a member such as a stainless steel film curtain at opposite sides thereof. A controlled gas feed system communicates with each of the chambers, and an ammonia gas feed system is connected to the soft-nitriding chamber.

Abstract: A combustion device of the type for atomizing liquid fuel by an ultrasonic atomizer and mixing the atomized fuel particles with air for combustion. A first air passage is defined around a horn of the ultrasonic atomizer by an inner cylinder, and a second air passage is defined around the first air passage by the inner cylinder and an outer cylinder. The air flowing through the first air passage is discharged into a cylindrical combustion section substantially in parallel with the axis thereof while the air flowing through the second air passage is swirled in the direction substantially tangential to the inner wall of the combustion section and discharged toward the atomizing surface of the horn, whereby the satisfactory mixing of the atomized fuel particles with the combustion air may be attained and the flame may be optimumly stabilized.