Ebara Corporation

Kazuo Takei

Hideomi Harada

Shunro Nishiwaki

Shin Konomi

Driven turbomachinery for use in centrifugal and mixed flow pump overcomes operational for overcoming difficulties, such as flow separation and generation of surge at low flow rates, often encountered in similar machines of the conventional design. The turbomachinery is provided with variable-angle inlet guide vane and variable-angle diffuser vanes, and the diffuser section is constructed according to a fluid dynamic principle, and the vanes having a wing shape are distributed tangentially so that the diffuser section acts as a centrifugal diffuser. A convenient operational parameter, chosen from such variables as input current to the drive motor, rotational speed or torque of the drive motor, inlet/exit pressures, and fluid velocity, is monitored during the operation by means of sensors strategically attached to parts of the operating system. Real-time changes in the operating parameter is measured and the setting angle of the inlet guide vane is adjusted in accordance with a predetermined relation between inlet flow volume rates and flow angle of the fluid exiting from the impeller so as to maintain the fluctuations in the monitored operating parameter below a threshold value. If the targeted head value is not produced under this adjustment, the setting angle of the diffuser vanes can also be adjusted based on real-time measurements of other operational parameters. If this adjustment fails to produce the targeted head value, then the rotational speed of the impeller can be adjusted to operate the system while avoiding surge and other problems encountered at flow rates.

Turbomachinery with variable-angle fluid guiding vanes

A turbomachine having variable angle diffuser vanes is demonstrated with the use of a centrifugal pump. The performance of a diffuser is enhanced greatly by the use of adjustable angle diffuser vanes which can be set to a wide range of vane angles to provide a variable size of an opening between adjacent vanes. The demonstrated pumping system has a significantly wider operating range than that in conventional pumping systems over a wide flow rate, and is particularly effective in the low flow range in which known diffuser vane arrangements would lead to surge in the entire system and other serious operational problems. A number of examples and formulae are given to demonstrate the computational methods used to select a vane angle for a given set of operating conditions of the turbomachine.

Turbomachine having variable angle flow guiding device

A turbomachine having variable-angle diffuser vanes operates by regulating the angle of the diffuser vanes on the basis of the sensors disposed on the pump body or pipes of a surge detection device. The onset of surge can be forecast by measuring the fluctuations in the operating parameter(s) over a measuring interval of time computed on the basis of the operating characteristics of the impeller of the turbomachine. The onset of surge is prevented by adjusting the angle of the diffuser vanes in accordance with the sampling duration for parameter fluctuations over the measuring interval of time, and by adjusting the diffuser vanes to maintain the operating parameter fluctuations of the fluid machinery below a threshold value of the turbomachine derived from the design flow rate of the turbomachine. Application of the surge detection device in combination with fluid flow guide vanes and blades of the turbomachine enables full utilization of the potential capability of the turbomachine.

Surge detection device and turbomachinery therewith

A turbomachine having variable angle diffuser vanes wed with a centrifugal pump. The performance of a diffuser is greatly enhanced by the use of adjustable angle diffuser vanes which can be set to a wide range of vane angles to provide a variable size of an opening between adjacent vanes. The demonstrated pumping system has a significantly wider operating range than that in conventional pumping systems over a wide flow rate, and is particularly effective in the low flow rate range in which known diffuser vane arrangements would lead to surge in the entire system and other serious operational problems.

Turbomachinery having variable angle flow guiding device

A turbomachinery is presented to provide stable operation at fluid flow rates much lower than the design flow rate without introducing surge in the device. This is achieved by providing a diffuser with variable angle vanes. The vane angle at low flow rates is adjusted so as to minimize the diffuser loss of the exiting fluid stream from the impeller. Since the flow angle of the exit flow of the impeller is a function only of the non-dimensional flow rates, and does not depend on the flow angle at the inlet the impeller, therefore, the vane angles can be regulated to achieve a stable operation of the impeller without producing surge of the turbomachinery at flow rates lower than the design flow rate. To optimize the performance of the turbomachinery, in addition to the variable angle vanes, an inlet guide vane having variable vane angle is provided so that the turbomachinery can be operated at the required flow rate and head pressure. The concept is demonstrated in a turbomachinery provided with variable diffuser vanes and an inlet guide vane.

Growing community of inventors

Kanagawa-ken, Japan

Kazuo Takei