Showing papers by "Nagai Makoto published in 1993"

Turbo fan and device mounted turbo fan

Abstract: PURPOSE:To uniform the speed distribution of air impeller output so as to reduce blast noise without cost increase by making the rate of local pressure rise at the impeller outlet large on the shroud side. CONSTITUTION:A turbo fan includes an impeller formed of an approximately disc like boss 3 provided with a motor driving shaft fitting hole, an annular hub 4 extended at the outer periphery of the boss 3, blades 5 planted on one face of the boss 3 spirally around the hole, and a shroud 6 opposed to the boss 3 with the blades placed in between. From a center axis to a specified distance R position, the cross section of the blade 5 on the plane vertical to the center axis is placed forward in the rotating direction as it approaches the center part of the impeller and shows spiral shape proceeding to the center axis almost from the outer peripheral part of the impeller, and a part close to the outer periphery of the impeller from the specified distance R position is bent so as to vertically approach the outer peripheral edge of the impeller. Accordingly, the outlet pressure of air flow rises locally so as to obtain the large air quantity.

Reduction of Noise Caused by Gas-Liquid Two-Phase Refrigerant Flow through an Expansion Valve.

Abstract: Presently, from the viewpoint of comfort in air conditioning, noise reduction is being a matter of importance. This study focuses on the problem of noise in indoor air conditioners caused by the refrigerant flowing through the expansion valve. We investigated a method by which to reduce the low-frequency intermittent flow noise. It is supposed that this intermittent flow noise is related to the flow pattern of the refrigerant through the expansion valve. We carried out an experimental investigation to establish a correlation between flow pattern of refrigerant and consequent noise. It is shown that the noise is reduced if the flow of refrigerant at the inlet area of the expansion valve is made continuous both in gas and liquid phases.

Centrifugal fan and manufacture thereof

Abstract: PURPOSE: To provide a thinned, noise-reduced centrifugal fan at reduced cost that provides a large quantity of air, for use in an air conditioner, air-cooled electronic equipment or an electric motor. CONSTITUTION: The bore of a side plate 3 is smaller than the outside diameter of a core plate 1 and a plurality of main vanes 2 are disposed at almost equal intervals on the core plate 1 and a plurality of auxiliary vanes 4 are mounted at almost equal intervals on that side of the side plate 3 which is opposite to the main vanes 2. The shapes of the main vane 2 and the auxiliary vane 4 are determined so that the main vane 2 and the auxiliary vane 4 are axially passed through respective trimming dies used in the manufacture of the main and auxiliary vanes. Therefore the centrifugal fan can provide low noise, high pressure and a large quantity of air as compared to conventional centrifugal and propeller fans and can be integrally molded and is therefore available at reduced cost. COPYRIGHT: (C)1994,JPO&Japio

Cold accumulation type air conditioning apparatus

Abstract: PURPOSE:To perform energy conservation by connecting one end of a cold accumulation heat exchanger to a liquid refrigerant tube between an outdoor unit pressure reducing mechanism and an indoor unit heat exchanger, branching the other end, connecting the one to the suction side of a compressor suction side, further branching the one, connecting the one to a gas refrigerant piping between the compressor and the indoor heat exchanger and connecting the other to a downstream of a flow control valve of the liquid refrigerant piping CONSTITUTION:One end of a heat exchanger 15 a cold accumulator 2 is connected to an outdoor side liquid refrigerant piping 11 for connecting indoor heat exchangers 3a, 3b to an outdoor unit 1 through a flow control valve 16, a piping 16a A flow control valve 18 is disposed at the side of the exchangers 3a, 3b from its connecting point On the other hand, the other end of the exchanger 15 of the accumulator 2 is connected to the suction side of a compressor 4 through a switching valve 19, a low pressure gas refrigerant piping 12, and connected to an outdoor side gas refrigerant piping 13 through a switching valve 20 Further, a switching valve 31 is connected to be branched from the inlet side of the value 20 between the vale 18 provided in the piping 11 and the exchangers 3a, 3b