Systems and methods for controlling working fluid in hydraulic elevators
US11198585B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 18, 2019 |
| Grant date | Dec 14, 2021 |
| Priority date | — |
| Expiry date | Feb 2, 2040 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B2211/8633
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A hydraulic elevator may comprise a bidirectional pump that controls up and down motion of an elevator car. A VVVF drive may cause the bidirectional pump to provide working fluid in a controlled manner to a hydraulic jack that supports the elevator car. A control valve may be disposed between the bidirectional pump and the hydraulic jack so that the control valve can be closed when the elevator car needs to be held in place. To avoid pressure waves that propagate when the control valve is opened with disparate pressures on the pump and jack sides of the control valve, the bidirectional pump may adjust the pressure on the pump side of the closed control valve to the pressure on the jack side of the control valve before the control valve is opened.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.