Johnson Controls Technology Company

York International Corporation

Kurt F Nenstiel

Jeb William Schreiber

Justin Patrick Kauffman

Steven Trent Sommer

Mark A Adams

An improved variable geometry diffuser (VGD) mechanism for use with a centrifugal compressor. This VGD mechanism extends substantially completely into the diffuser gap so that the VGD mechanism may be used more fully to control other operational functions. The VGD mechanism may be used to minimize compressor backspin and associated transient loads during compressor shut down by preventing a reverse flow of refrigerant gas through the diffuser gap during compressor shutdown, which is prevented because the diffuser gap is substantially blocked by the full extension of the diffuser ring. During start-up, transient surge and stall also can be effectively eliminated as gas flow through the diffuser gap can be impeded as load and impeller speed increase, thereby alleviating the problems caused by startup loads at low speeds. The VGD mechanism can be used for capacity control as well so as to achieve more effective turndown at low loads.

Variable geometry diffuser having extended travel and control method thereof

A system for preventing stall in a centrifugal compressor. The compressor includes an impeller rotatably mounted in a housing and a nozzle base plate fixed to the housing adjacent the impeller. The nozzle base plate cooperates with the housing to define a diffuser gap. The base plate includes a plurality of mechanism support blocks positioned on the backside of the nozzle base plate. A drive ring, mounted to the support blocks, is rotationally moveable with respect to the support blocks and the nozzle base plate between a first position and a second position. Connected to the drive ring is a diffuser ring that moves in response to movement of the drive ring. Diffuser ring moves between a retracted position that is not within the diffuser gap and an extended position extending into the diffuser gap to constrict the gap opening and reduce the flow of fluid through the diffuser gap. The diffuser ring can be positioned at any location between the retracted and extended position to control the amount of fluid flowing through the diffuser gap.

Variable geometry diffuser mechanism

A tube support includes at least two parallel plates. With more than two plates, the outer plates are longer in the direction of flow than the inner plates. Pins are provided proximate the leading and trailing edges of the plates in order to maintain the plates in a spaced relationship. The pins proximate each edge are positioned slightly over two tube diameters from the other pins along the same edge. Additionally, the pins along the trailing edge are positioned approximately one tube diameter from the pins proximate the leading edge in a direction along the edge in order to stagger the leading and trailing pins.

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York, PA, United States of America

Kurt F Nenstiel