Air assemblies (1000,2000,3000,4000,5000) having an inflation, a deflation, and a closed state for use with inflatable products, such as air mattresses. Specifically, air assemblies (1000,2000,3000,4000,5000) can be changed manually by a user by operating a directional control valve (1033,2043,3033,4033,5001) to inflate, deflate, or close the inflatable product. The directional control valve (1033,2043,3033,4033,5001) may also activate a pump in the inflation and deflation states and deactivate the pump in the closed state.

The present invention relates to a sealing system for a pump configured to pressurize a volatile liquid, such as liquid ammonia. The sealing system (2) includes a stuffing box (35) forming a barrier chamber (30) and a pump-side seal chamber (43), a mechanical seal (20) arranged in the barrier chamber (30), and a barrier-gas supply system (32) for supplying a barrier gas into the barrier chamber (30). The barrier gas has a pressure higher than a pressure of the volatile liquid in the pump-side seal chamber (43). The pump-side seal chamber (43) is located between an impeller (7) of the pump (1) and the mechanical seal (20). The barrier-gas supply system (32) includes a pressure control valve (50) configured to maintain a constant difference between pressure in the barrier chamber (30) and pressure in the pump-side seal chamber (43).

A throttle valve for a centrifugal compressor includes a body having a central passage and one or more diverter flow paths. The central passage is formed by an inner surface of the body, each diverter flow path has an inlet and an outlet, and the one or more diverter flow paths are configured to induce a swirl within a fluid flow through the central passage while a portion of the fluid flow passes through the one or more diverter flow paths. The throttle valve also includes at least one blade disposed within the central passage. The at least one blade is configured to direct the portion of the fluid flow to the inlets of the one or more diverter flow paths while the at least one blade is in a partially open position.

A system of interlocks for controlling flow of low temperature process streams in a manufacturing process through a cold box to equipment or piping not specified for such temperatures by opening and closing valves and starting and stopping pumps. At least one interlock affects streams heated in the cold box. At least one interlock affects the streams cooled in the cold box. The interlocks are activated by temperatures of process lines to prevent exposure of equipment and piping to low temperatures while preventing the shutdown of the cold box. An override controller including a predictive failure capability is also provided.

The water-conserving liquid ring vacuum pump system receives the output from a water ring vacuum pump, removes the air and contaminants from the water, and returns the clean water to the make-up water port on the pump, thereby saving most of the water that would normally be discarded. Friction in the pump also heats the water, so the system is designed to cool the water as well.

The purpose of the present invention is to provide a gas compressor capable of reducing variation in discharge pressure through control of the number of compressor bodies and a control method for the gas compressor. In order to solve the problem, this gas compressor includes a plurality of compressor units each having a compressor body, a motor for driving the compressor body, and an inverter for controlling a rotational speed of the motor, and a control device for controlling the inverters. Discharge pipes of the compressor bodies converge on one main discharge pipe. A drive frequency of the motor of each compressor body is controlled by the corresponding inverter, whereby a pressure of each discharge pipe is controlled and a discharge pressure of the main discharge pipe is controlled. When the discharge pressure of the main discharge pipe has increased in a period of reduction in the drive frequency of the motor of the compressor body before the drive frequency reaches a lower-limit frequency, the control device calculates a prediction time for reaching a stopping pressure. The control device stops one of the compressor bodies when the prediction time is less than a threshold value.

An electronic system includes a fan module, an embedded controller, an error microphone, an active noise cancellation controller, and a micro speaker module. The error microphone is configured to output an error signal by detecting the noise level during the operation of the electronic system. According to the error signal and the fan information provided by the embedded controller, the active noise cancellation controller calculates the narrow-band noises associated with the actual single-blade fundamental frequency noise and the actual BPF fundamental frequency noise generated by the fan module, and drives the micro speaker module accordingly for providing a noise cancellation signal. The error signal may be reduced to zero by adaptively adjusting the noise cancellation signal for canceling the noises generated during the operation of the electronic system.

An electronic system includes a fan module, an embedded controller, an error microphone, an active noise cancellation controller, and a micro speaker module. The error microphone is configured to output an error signal by detecting the noise level during the operation of the electronic system. According to the error signal and the fan information provided by the embedded controller, the active noise cancellation controller calculates the narrow-band noises associated with the actual single-blade fundamental frequency noise and the actual BPF fundamental frequency noise generated by the fan module, and drives the micro speaker module accordingly for providing a noise cancellation signal. The error signal may be reduced to zero by adaptively adjusting the noise cancellation signal for canceling the noises generated during the operation of the electronic system.

Provided area second-order sliding mode observation-based fan power control method and system. The method includes: calculating, by second-order sliding mode observation, an observed rotational speed value of a fan, and calculating a maximum power reference current corresponding to maximum power of the fan according to a relational expression between the rotational speed and maximum power point; and performing, by controlling a Pulse Width Modulation (PWM) switch to be toggled, system Maximum Power Point Tracking (MPPT) according to the maximum power reference current, so as to control the fan to operate stably at the maximum power point.

Provided area second-order sliding mode observation-based fan power control method and system. The method includes: calculating, by second-order sliding mode observation, an observed rotational speed value of a fan, and calculating a maximum power reference current corresponding to maximum power of the fan according to a relational expression between the rotational speed and maximum power point; and performing, by controlling a Pulse Width Modulation (PWM) switch to be toggled, system Maximum Power Point Tracking (MPPT) according to the maximum power reference current, so as to control the fan to operate stably at the maximum power point.