Abstract: Specifications of the impeller and the scroll type casing of a multiblade radial fan comprising an impeller having numerous radially directed blades circumferentially spaced from each other and a scroll type casing accommodating the impeller are determined so as to make divergence angle of the scroll type casing substantially coincide with divergence angle of the free vortex formed by the air discharged from the impeller.

Abstract: Noise is minimized in the design of multiblade radial fans, wherein the specifications of the impeller of a multiblade radial fan are determined so as to satisfy the correlation expressed by the formula .nu..gtoreq.-0.857Z.sub.1 +1.009 (in the preceding formula, .nu.=r.sub.0 /r.sub.1, Z.sub.1 =(r.sub.1 -r.sub.0)/?r.sub.1 -nt/(2.pi.), where r.sub.0 is the inside radius of the impeller, r.sub.1 is the outside radius of the impeller, n is the number of radially-directed blades, and t is the thickness of the radially-directed blades).

Abstract: A flush toilet stool includes a toilet bowl and a trap drainage passage connected to the toilet bowl. The toilet bowl has a water jet hole defined in a bottom region thereof and opening toward the trap drainage passage. A pressurizing unit such as a water pump is coupled to the water jet hole for drawing water under lower pressure directly from an external water supply and expelling the water under higher pressure through the water jet hole toward the trap drainage passage to develop a siphon flow to discharge sewage from the toilet bowl through the trap drainage passage.

Abstract: A water closet flushing apparatus provided with a pressure detector mounted along a water supply pipe, an opening and closing apparatus to open and close a water supply passage provided along the water supply pipe and a control apparatus that uses the pressure detected by the pressure detector to control the opening and closing operation of the opening and closing apparatus so that a predetermined amount of water is supplied to the water closet.

Abstract: A water closet flushing apparatus provided with a pressure detector mounted along a water supply pipe, an opening and closing apparatus to open and close a water supply passage provided along the water supply pipe and a control apparatus that uses the pressure detected by the pressure detector to control the opening and closing operation of the opening and closing apparatus so that a predetermined amount of water is supplied to the water closet.

Abstract: A water closet flushing apparatus provided with a pressure detector mounted along a water supply pipe, an opening and closing apparatus to open and close a water supply passage provided along the water supply pipe and a control apparatus that uses the pressure detected by the pressure detector to control the opening and closing operation of the opening and closing apparatus so that a predetermined amount of water is supplied to the water closet.

Abstract: In a water closet flushing apparatus of the type in which the flushing water from a flushing water supply source is fed through different flushing water feed lines to a bowl portion and a trap discharge passage defined adjacent to the bottom portion of the bowl portion, a water jet injector is provided so as to inject the flushing water jet toward the trap discharge passage, an opening-closing valve is disposed in each of different feed lines, and the operation of the opening-closing valve is controlled by a control unit. The flushing water is flushed into the bowl portion so as to clean the same while the jet of flushing water is injected into the trap discharge passage to cause the same to act as a siphon, whereby waste matter is discharged.