Bell mouth

About: Bell mouth is a research topic. Over the lifetime, 603 publications have been published within this topic receiving 1624 citations.

Improvement of Intake Structures in a Two-Way Pumping Station with Experimental Analysis

Abstract: Pumping stations are important regulation facilities in a water distribution system. Intake structures can generally have a great influence on the operational state of the pumping station. To analyze the effects of the bell mouth height of the two-way intake on the performance characteristics and the pressure pulsations of a two-way pumping station, the laboratory-sized model pump units with three different intakes were experimentally investigated. To facilitate parameterized control, ellipse and straight lines were used to construct the profile of the bell mouth. The frequency domain and time-frequency domain of the pressure pulsations on the wall of intakes were analyzed by the Welch’s power spectral density estimate and the continuous wavelet transform (CWT) methods, respectively. The results showed that the bell mouth height (H) has significant influences on the uniformity of the impeller inflow and the operation stability of the pump unit. When H = 204 mm, the data fluctuated greatly throughout the test process and the performance curves are slightly lower than the other two schemes. As the bell mouth height gradually decreases, the average pressure difference of each measuring point began to decrease, more homogeneous velocity distribution of impeller inflow can be ensured. The amplitude of blade passing frequency is obvious in the spectrum. While when (H) is more than 164 mm, the main frequency of pressure pulsations at three points fluctuates with the rotation of the impeller. When H decreases to 142 mm, pressure pulsations will be independent of the operating conditions and positions which contributes to the long-term stable operation of the pump unit.

Flow straightening duct and gas flow measuring device

Abstract: PURPOSE:To heighten the generality-of-use of a flow straightening duct and attain cost reduction by dividing a flow straightening throttle element into the common upstream side and the downstream side replaceable according to a flow meter, and jointing them in such a way as not to generate step difference to the connecting part CONSTITUTION:Air flow passes a filter 12 held among a bell mouth 4 and meshes 10, 11, a flow assisting part 3 and a flow straightening grid 6, and flows into an upstream side throttle element 1 The air further flows into a downstream side throttle element 2 after passing a flow straightening grid 5 and flows out to a flow meter or the like outside a flow straightening duct A connecting part between the throttle elements 1, 2, the inlet of the throttle element 1 and the outlet of the throttle element 2 are provided at points or blocks where an angle Q formed by the tangent of the curved inner wall surface and the main flow axial direction is changed continuously so as not to generate fluid separation in the vicinity of the inner wall surface, and connected in such a way that the angle Q at each connecting part is to be zero and the rate-of- change DELTAQ/DELTAX of the angle Q is to be zero The connecting parts are jointed removably by bolts and nuts

Spinning device and spinning method for segment-colour yarn

Abstract: The invention discloses a spinning device and a spinning method for a segment-colour yarn. A four-roller stretching and multi-rough yarn feeding method, and a special shaped rear leather roller and a middle-rear leather roller are introduced into a production system, and a foundation is laid for further enriching the appearance styles of yarns. The device is characterized in that four rollers are adopted in a stretching system, and the four rollers are all controlled by adopting a single servo motor; rough yarns are fed in the following mode: a first rough yarn feeding bell mouth is additionally formed in the front part of a rear roller; a first fibre strand collecting bell mouth and a second fibre strand collecting bell mouth are additionally formed in the upper parts of a middle-rear roller and a middle-front roller; a first rough yarn, a second rough yarn and a third rough yarn are respectively fed through a first left front bell mouth, a first middle front bell mouth and a first right front bell mouth of a first rough yarn feeding bell mouth; the rear leather roller and the middle-rear leather roller are special shaped rollers and comprise a left shaft and a right shaft with different diameters; a spinning process comprises three spinning states, namely, a single-colour yarn segment spinning state, a double-colour yarn segment spinning state, and a three-colour yarn segment spinning state.

Indoor unit for air conditioner, and air conditioner with indoor unit

Abstract: An indoor unit (100) for an air conditioner has an air blowing device (4) provided upstream of a heat exchanger (5). The air blowing device (4) of the indoor unit (100) has a bell mouth (12) which is provided at the suction opening (2) of a casing (1), an axial or diagonal flow fan (13) which is provided on the inner peripheral side of the bell mouth (12), a motor (8) which drives and rotates the fan (13), a motor base (10) which holds the motor (8), and a motor stay (11) which connects the motor base (10) and the bell mouth (12). The motor stay (11) of the air blowing device (4) is formed in such a manner that, in a plan view, the downstream end of each of the blades (15) of the fan (13) intersects any one of bar-like members irrespective of the rotational angle of the fan (13), the bar-like members constituting the motor stay (11).

Novel anti-seepage inspection structure of precast pipe galleries

Abstract: The utility model discloses a novel anti-seepage inspection structure of precast pipe galleries. The anti-seepage inspection structure is used for the butted sealing position of the adjacent pipe galleries, and comprises a faucet and a bell mouth which is matched with the faucet, wherein the faucet and the bell mouth are inserted mutually by a faucet working surface and a bell mouth working surface. The anti-seepage inspection structure is characterized in that a first annular sealing element and a second annular sealing element which are used for preventing seepage and are arranged in the axial direction are arranged between the faucet working surface and the bell mouth working surface; the first sealing element and the second sealing element and a part of the faucet working surface and the bell mouth working surface which is positioned between the first sealing element and the second sealing element form an annular sealing cavity jointly; the radius of the first sealing element is equal to that of the second sealing element; an exhaust port and a water injection hole are formed in the upper wall and lower wall of the faucet respectively; and the exhaust port and the water injection hole are communicated with spaces in the sealing cavity and the faucet. According to the anti-seepage inspection structure, water passing detection can be performed comprehensively at joints without the completion of the integral pipe galleries due to the sealing cavity, so that inspection is flexible and rapid and water is saved; and if seepage occurs at the joints due to failure, the joints can be repaired quickly and simply by the anti-seepage inspection structure, so the anti-seepage inspection structure has high economy and reliability.