Abstract: Disclosed is an underbalanced drilling vibrating screen integrated with automatic drainage and vacuum chucks, and belongs to the technical field of solid-phase control of petroleum drilling. The underbalanced drilling vibrating screen comprises a base, a screening device and a negative pressure generating device, wherein the screening device and the negative pressure generating device are arranged on the base; the screening device comprises a shell, an exciting motor arranged on the shell, a plurality of screens arranged in the shell, and at least one drainage component; and the drainage component communicates with at least one screen through the vacuum chuck, the negative pressure generating device communicates with the vacuum chuck, and the drainage component is integrally formed with the vacuum chuck.

Abstract: A negative pressure shale shaker integrated with negative pressure generation and gas-liquid separation includes a base, a liquid inlet buffer tank, a screen frame assembly, a support frame, a vacuum hose, a damping spring, a screen frame inclination angle adjustment device, a drainage hose, a negative pressure automatic drainage device, a vacuum pan, a three-way pipe, a liquid mist separator, a connecting pipe, a vacuum pressure limiting valve, a silencer and a negative pressure fan. A drilling fluid containing cuttings, after entering the screen with a negative pressure thereunder, rapidly passes through the screen along with air into a vacuum chamber. The air in the vacuum chamber is directly drawn away through holes formed on the side plates of the screen frame by the negative pressure fan.

Abstract: An ultra-long stroke multi-cylinder reciprocating pump comprises a small gear, a large gear, a crankshaft, connecting rods, fixed racks, a frame, translation pinions, movable racks, clamps, piston rods, cylinder sleeves, pistons, suction valves, liquid discharging valves, guide rails, a prime motor, a coupling, and a small gear shaft. When the prime motor rotates, the small gear is meshed with the large gear to drive the crankshaft to rotate, an axial center of the translation pinion is driven by the connecting rod to move reciprocally, the translation pinion is meshed with the fixed rack and the movable rack simultaneously, and a distance of reciprocating motion of the movable rack is twice a distance of reciprocating motion of a rotation center of the translation pinion, so that an ultra-long stroke is realized.

Abstract: Disclosed is an independent double-negative-pressure shale shaker, and belongs to the technical field of petroleum drilling solid control. The independent double-negative-pressure shale shaker comprises a base, a fluid discharge device, an inclination angle adjustment mechanism, a screening device, an exciting motor and a double-negative-pressure system, wherein the double-negative-pressure system comprises a first negative-pressure system and a second negative-pressure system which are relatively independent; the first negative-pressure system dries drilling fluid of a first screen mesh set close to a material outlet, and the second negative-pressure system increases the treatment capacity of drilling fluid of a second screen mesh set close to the first screen mesh set; and meanwhile, in the deep well section, the second negative-pressure system can be switched to a fluid mist suction state, fluid mist on the screen surface is reduced, the safety is improved, and the pollution of fluid mist is reduced.

Abstract: A negative pressure shale shaker integrated with negative pressure generation and gas-liquid separation includes a base, a liquid inlet buffer tank, a screen frame assembly, a support frame, a vacuum hose, a damping spring, a screen frame inclination angle adjustment device, a drainage hose, a negative pressure automatic drainage device, a vacuum pan, a three-way pipe, a liquid mist separator, a connecting pipe, a vacuum pressure limiting valve, a silencer and a negative pressure fan. A drilling fluid containing cuttings, after entering the screen with a negative pressure thereunder, rapidly passes through the screen along with air into a vacuum chamber. The air in the vacuum chamber is directly drawn away through holes formed on the side plates of the screen frame by the negative pressure fan.

Abstract: An ultra-long stroke multi-cylinder reciprocating pump comprises a small gear, a large gear, a crankshaft, connecting rods, fixed racks, a frame, translation pinions, movable racks, clamps, piston rods, cylinder sleeves, pistons, suction valves, liquid discharging valves, guide rails, a prime motor, a coupling, and a small gear shaft. When the prime motor rotates, the small gear is meshed with the large gear to drive the crankshaft to rotate, an axial center of the translation pinion is driven by the connecting rod to move reciprocally, the translation pinion is meshed with the fixed rack and the movable rack simultaneously, and a distance of reciprocating motion of the movable rack is twice a distance of reciprocating motion of a rotation center of the translation pinion, so that an ultra-long stroke is realized.

Abstract: The invention discloses a switching power supply, a primary control chip and a loop compensation device thereof.

Abstract: The present disclosure provides a control apparatus of a switch-mode power supply and a switch-mode power supply. In the control apparatus of the present disclosure, a short-circuit protection module is set, and when a switching transistor of the switch-mode power supply is turned on, and the short-circuit protection module detects that a voltage across a current sensing resistor of the switch-mode power supply is less than a predetermined value within a predetermined period, that is, the current sensing resistor is short-circuited, the short-circuit protection module generates a short-circuit protection signal, and a driving controller controls the switching transistor to turn off according to the protection signal, thereby switching off the control apparatus, preventing breakdown of the switch-mode power supply, and avoiding erroneous protection.

Abstract: The present disclosure provides a control apparatus of a switch-mode power supply and a switch-mode power supply. In the control apparatus of the present disclosure, a short-circuit protection module is set, and when a switching transistor of the switch-mode power supply is turned on, and the short-circuit protection module detects that a voltage across a current sensing resistor of the switch-mode power supply is less than a predetermined value within a predetermined period, that is, the current sensing resistor is short-circuited, the short-circuit protection module generates a short-circuit protection signal, and a driving controller controls the switching transistor to turn off according to the protection signal, thereby switching off the control apparatus, preventing breakdown of the switch-mode power supply, and avoiding erroneous protection.

Abstract: The invention discloses a switching power supply, a primary control chip and a loop compensation device thereof.

Abstract: A secondary control device and a charging system are provided. The secondary control device is connected with a transformer having a secondary winding connected with a charging interface, and includes: a secondary rectifier switch connected with the secondary winding; a secondary synchronous rectifier chip connected with the secondary winding and the secondary rectifier switch, and configured to detect a voltage between two terminals of the secondary rectifier switch, to control the secondary rectifier switch to turn on or turn off according to the voltage, to control the secondary rectifier switch to turn on again when the secondary rectifier switch is in an off-state so as to control the secondary winding to generate a mutation voltage, to obtain a transmission signal on the charging interface, and to control a driving voltage of the secondary rectifier switch according to the transmission signal so as to adjust the mutation voltage.

Abstract: An integrated circuit controls a switch power supply including: a primary feedback terminal, a primary feedback sampling module, an error amplifying module, a first control module, a secondary control module, a secondary feedback terminal, a second control module, and a driving module; the second control module, connected with the first control module and the secondary control module, respectively, and configured to generate a logic control signal according to the constant voltage control signal, or according to the secondary control signal and the constant voltage control signal; and the driving module, connected with the second control module and configured to generate a driving signal according to the logic control signal and to output the driving signal.

Abstract: An integrated circuit controls a switch power supply including: a primary feedback terminal, a primary feedback sampling module, an error amplifying module, a first control module, a secondary control module, a secondary feedback terminal, a second control module, and a driving module; the second control module, connected with the first control module and the secondary control module, respectively, and configured to generate a logic control signal according to the constant voltage control signal, or according to the secondary control signal and the constant voltage control signal; and the driving module, connected with the second control module and configured to generate a driving signal according to the logic control signal and to output the driving signal.

Abstract: A system comprises a disk writer servo head and a controller. The disk writer servo head is configured to be positioned by a micro actuator. The disk writer servo head is also configured to substantially, continuously alternate between reading a first servo pattern and writing a second servo pattern until a disk is substantially, completely servo written. The first servo pattern establishes a first position of the disk writer servo head and the second servo pattern establishes a second position of the disk writer servo head. The controller is configured to control the operation of the disk writer servo head. The controller is also configured to compare the first and second positions to establish a position error. The micro actuator is configured to reposition the disk writer servo head in response to the position error prior to a next reading.

Abstract: A quasi-resonant device for a switching power, a quasi-resonant system for a switching power, and a method for a quasi-resonant control of a switching power are provided. The quasi-resonant device includes: a degaussing time sampling module, configured to sample a degaussing time Tds of a secondary coil of the transformer according to a feedback signal output by the switching power after the switching tube is turned off; a valley sampling module, configured to sample a resonant valley signal of the quasi-resonant module according to the feedback signal; a time producing module, configured to produce a time T with a predetermined ratio D by processing the degaussing time Tds; and a logic processing module, configured to obtain a first valley signal after the time T, and the first valley signal works as a switching signal T? to turn on the switching tube.

Abstract: A quasi-resonant device for a switching power, a quasi-resonant system for a switching power, and a method for a quasi-resonant control of a switching power are provided. The quasi-resonant device includes: a degaussing time sampling module, configured to sample a degaussing time Tds of a secondary coil of the transformer according to a feedback signal output by the switching power after the switching tube is turned off; a valley sampling module, configured to sample a resonant valley signal of the quasi-resonant module according to the feedback signal; a time producing module, configured to produce a time T with a predetermined ratio D by processing the degaussing time Tds; and a logic processing module, configured to obtain a first valley signal after the time T, and the first valley signal works as a switching signal T? to turn on the switching tube.