Abstract: A device and a method for nondestructively detecting a transient characteristic of a conductive screw of a turbo-generator rotor are provided. The device includes a personal computer (PC), an extremely-steep pulse generator, an ultra-high-frequency double-isolation transformer, and a pulse emitting and coupling module, which are connected in sequence. The pulse emitting and coupling module is connected to a load. A synchronous pulse receiving non-inductive divider circuit synchronously receives a characteristic waveform from the load, and the synchronous pulse receiving non-inductive divider circuit is connected to an ultra-high-speed analog/digital (A/D) module through a nonlinear saturation amplifying circuit that amplifies a signal. The PC receives a signal from the ultra-high-speed A/D module. The load includes a positive or negative excitation lead loop that is in a 180° symmetrical and instantaneous short-circuit state and a rotor shaft.

Abstract: A device for detecting a slot wedge, an air gap and a broken rotor bar is provided, where a sequential circuit generates double concurrent pulses; the sequential circuit is connected to driving power modules; the driving power modules are connected to front-end interface circuits; the front-end interface circuits convert the double concurrent pulses into corresponding magnetic-field pulses; the magnetic-field pulses are transmitted to power supply terminals on adjacent phases of stator windings through impedance matching pins and coupled at a corresponding coil, air gap and squirrel cage rotor to generate single groups of cyclic rotating magnetic potentials; single rotating magnetic potentials are sequentially generated in adjacent slots on each of the phases of the stator windings; rotating electric potentials in magnetic circuits with two symmetrical phases are magnetically coupled to form distributed coupling magnetic field reflected full-cycle waves for reflecting a difference of a corresponding slot wedg

Abstract: A heat exchanger having: a first heat exchanger core including a first sub-heat exchanger core and a second sub-heat exchanger core, wherein the first sub-heat exchanger core and the second sub-heat exchanger core includes heat exchange tubes, the heat exchange tubes of the first sub-heat exchanger core and the second sub-heat exchanger core are connected to each other, and orthographic projections of the first sub-heat exchanger core and the second sub-heat exchanger core on a plane where the second sub-heat exchanger core is located at least overlap partially; and a second heat exchanger core including a heat exchange tube, wherein the heat exchange tube of the second heat exchanger core is connected to the heat exchange tubes of the first sub-heat exchanger core and the second sub-heat exchanger core is disclosed.

Abstract: A heat exchanger includes: a manifold having a manifold opening passing through a pipe wall of the manifold; a distribution pipe disposed in the manifold and having a distribution pipe opening passing through a pipe wall of the distribution pipe; and a connecting pipe assembly including a first connecting pipe The first connecting pipe is inserted in the manifold opening, has an end connected to the distribution pipe at the distribution pipe opening, and is in fluid communication with the distribution pipe. Thereby, the space occupied by the connecting pipe assembly in the manifold can be reduced.

Abstract: The present disclosure discloses a heat exchanger and an air conditioning system having the heat exchanger. The heat exchanger includes a first heat exchanger core, a second heat exchanger core and a connection part. Heat exchange tubes of the first heat exchanger core and the second heat exchanger core include first circuit heat exchange tubes. A length of the heat exchange tube of the first heat exchanger core is greater than a length of the heat exchange tube of the second heat exchanger core. The connection part includes a first connection part through which the first circuit heat exchange tubes of the first heat exchanger core are connected with the first circuit heat exchange tubes of the second heat exchanger core. The heat exchange tubes of at least one of the first heat exchanger core and the second heat exchanger core further include second circuit heat exchange tubes.

Abstract: A heat exchanger (100), the heat exchanger (100) including: a plurality of heat exchange tubes (1) arranged in a first direction and extending in a second direction perpendicular to the first direction; and a plurality of fins (2) provided between every two adjacent heat exchange tubes (1) and in contact with one another, each fin (2) including a curved surface portion. The heat exchanger is able to increase the heat exchange area.

Abstract: A distribution pipe assembly (1) for a heat exchanger (100), a header assembly (20) having the distribution pipe assembly (1), and a heat exchanger (100). The distribution pipe assembly (1) includes a first distribution pipe, the first distribution pipe comprising: a main wall (10) extending in a first direction (D1) serving as an axial direction, and having a first side (11) in a second direction (D2) perpendicular to the first direction (D1), and a second side (12) in the second direction (D2) opposite the first side (11); and a protruding wall (3) protruding, in the second direction (D2), from the main wall (10). The distribution pipe assembly (1) and the heat exchanger (100) improve heat exchange performance of the heat exchanger (100).

Abstract: Embodiments of the present invention disclose a heat exchanger and an air-conditioning system. The heat exchanger includes heat exchange tubes. The heat exchange tubes include first heat exchange tubes configured to form a first circuit, and second heat exchange tubes configured to form a second circuit. With the heat exchanger according to the embodiments of the present invention, if one of two circuits of a two-circuit air-conditioning system is turned off, a heat exchange efficiency of the heat exchanger can be improved.

Abstract: A preparation method for 2,3-pentanedione, including the steps of adding one or both of 3-hydroxy-2-pentanone and 2-hydroxy-3-pentanone into water and conducting mixing, and introducing ozone at the temperature of 3-20° C. for a reaction to obtain 2,3-pentanedione. The synthesis process of the present invention uses ozone for oxidizing a mixture containing 3-hydroxy-2-pentanone and 2-hydroxy-3-pentanone, acetic acid is used as a cocatalyst, reaction conditions are mild, the operation process is simple, the product yield is high, and the cost is low.

Abstract: A preparation method for 2,3-pentanedione, including the steps of adding one or both of 3-hydroxy-2-pentanone and 2-hydroxy-3-pentanone into water and conducting mixing, and introducing ozone at the temperature of 3-20° C. for a reaction to obtain 2,3-pentanedione. The synthesis process of the present invention uses ozone for oxidizing a mixture containing 3-hydroxy-2-pentanone and 2-hydroxy-3-pentanone, acetic acid is used as a cocatalyst, reaction conditions are mild, the operation process is simple, the product yield is high, and the cost is low.

Abstract: A heat exchanger system is disclosed by embodiments of the present invention. The heat exchanger system comprises an upper manifold, a middle manifold and a lower manifold arranged successively from top to bottom, wherein a first heat-exchanging tube is arranged between the upper manifold and the middle manifold, and a second heat-exchanging tube is arranged between the middle manifold and the lower manifold. The middle manifold has a first chamber and a second chamber separated from each other. During circulation of refrigerant, the refrigerant in the upper manifold flows through the first heat-exchanging tube down to the first chamber, and flows via a first communicating part into the chamber of the lower manifold, and subsequently the refrigerant flows through the second heat-exchanging tube up into the second chamber and then returns via a second communicating part to the upper manifold.

Abstract: A method for manufacturing a refrigerant guide tube of a heat exchanger and a refrigerant guide tube manufactured using the method and a heat exchanger with the refrigerant guide tube are disclosed. The refrigerant guide tube includes tube body and channels extending through a wall of the tube body. The tube body is formed by a butt joint of side edges of more than one bar-shaped plate materials along the length direction. The method allows forming the refrigerant channels of the guide tube before or during forming the tube body when the method is used to manufacture the guide tube, so as to avoid directly forming the channels on the tube body and make the process of manufacture the guide tube simpler and more convenient.

Abstract: A heat exchanger comprises a first header (1), a second header (2) spaced apart from the first header (1) by a predetermined distance, flat tubes (3) each of which defines two ends connected to the first and second headers (1, 2), respectively, to communicate the first and second headers (1, 2), fins (4) interposed between adjacent flat tubes (3), and a flow member defining a fluid-flow passage and forming a partition-wall-type heat-exchanging unit with the second header (2). A refrigeration system comprises a compressor, a condenser, a throttle device, and an evaporator that is the heat exchanger. The compressor, condenser, throttle device, and evaporator are connected sequentially, and at least part of refrigerant flowing out of an outlet of the condenser enters into the flow member to exchange heat with a refrigerant flowing out of an outlet of the evaporator.

Abstract: An evaporator (500) comprises a first header (501) defining one end formed with a first refrigerant port (5010), a second header (502) defining one end formed with a second refrigerant port (5020), heat-exchange tubes (503) each connected between the headers (501, 502) to communicate the headers (501, 502), fins (504) respectively interposed between adjacent heat-exchange tubes (503), and a defrosting tube (505) defining a first end connected to one of the headers (501, 502) to communicate with an interior of the one header. A position of the first end of the defrosting tube (505) is spaced apart from the one end of the one header by a predetermined distance. A refrigeration system comprises the evaporator. By providing the defrosting tube (505), defrosting speed is increased, defrosting time is shortened, and energy efficiency of the refrigeration system is improved.

Abstract: A heat exchanger comprises a first header (1), a second header (2) spaced apart from the first header (1) by a predetermined distance, flat tubes (3) each of which defines two ends connected to the first and second headers (1, 2), respectively, to communicate the first and second headers (1, 2), fins (4) interposed between adjacent flat tubes (3), and a flow member defining a fluid-flow passage and forming a partition-wall-type heat-exchanging unit with the second header (2). A refrigeration system comprises a compressor, a condenser, a throttle device, and an evaporator that is the heat exchanger. The compressor, condenser, throttle device, and evaporator are connected sequentially, and at least part of refrigerant flowing out of an outlet of the condenser enters into the flow member to exchange heat with a refrigerant flowing out of an outlet of the evaporator.

Abstract: A refrigerant-distributing device and a heat exchanger comprising the refrigerant-distributing device are provided. The refrigerant-distributing device comprises a distributing tube (1) defining a first end and a second end in a length direction thereof and a plurality of nozzles (2) disposed on the distributing tube (1) along the length direction of the distributing tube, each nozzle having a predetermined length and being formed with a through-hole (21) communicating an interior of the distributing tube and an exterior of the distributing tube. By provision of the nozzles, the flow resistance is increased, and the refrigerant-flow rate is more uniform along the length direction of the distrusting tube. In addition, the refrigerant can be ejected along the radial direction, the axial direction, the circumferential direction, and other directions so that the uniformity of the refrigerant in the space outside the distributing tube is improved.

Abstract: An evaporator (500) comprises a first header (501) defining one end formed with a first refrigerant port (5010), a second header (502) defining one end formed with a second refrigerant port (5020), heat-exchange tubes (503) each connected between the headers (501, 502) to communicate the headers (501, 502), fins (504) respectively interposed between adjacent heat-exchange tubes (503), and a defrosting tube (505) defining a first end connected to one of the headers (501, 502) to communicate with an interior of the one header. A position of the first end of the defrosting tube (505) is spaced apart from the one end of the one header by a predetermined distance. A refrigeration system comprises the evaporator. By providing the defrosting tube (505), defrosting speed is increased, defrosting time is shortened, and energy efficiency of the refrigeration system is improved.

Abstract: A method for manufacturing a refrigerant guide tube of a heat exchanger and a refrigerant guide tube manufactured using the method and a heat exchanger with the refrigerant guide tube are disclosed. The refrigerant guide tube includes tube body and channels extending through a wall of the tube body. The tube body is formed by a butt joint of side edges of more than one bar-shaped plate materials along the length direction. The method allows forming the refrigerant channels of the guide tube before or during forming the tube body when the method is used to manufacture the guide tube, so as to avoid directly forming the channels on the tube body and make the process of manufacture the guide tube simpler and more convenient.