US 4,011,735 AGranted

Blower system and control system therefor

AssigneeWestinghouse Electric Corp.

InventorsLyle F. Martz, John W. Nanz

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Abstract

An automatic control system for high pressure blower applications prevents surging under variable supply flow rate requirements and achieves maximum efficiency of operation. The supply flow rate establishes the set point of a proportional plus reset controller, the latter receiving a feedback signal corresponding to the static discharge pressure of the supply blower and responding thereto for controlling the output of the supply blower. A return blower is controlled either through a characterizer relay in proportion to the control of the supply blower to maintain a fixed precalibrated relationship between supply and return flow rates or by a further proportional plus reset controller responsive to the supply flow rate, for establishing the set point thereof, and to the return flow rate, as a feedback signal thereto, for controlling the output of the return blower.

Claims7

Dependent claims

A blower system for a central air conditioning installation servicing a facility having variable air supply flow rate requirements in accordance with attaining desired atmospheric conditions within each portion of the facility serviced by the installation, comprising:

a supply blower,
duct means connected to said supply blower for receiving and conveying an air supply flow from said supply blower to air conditioning means, the air as conditioned therein being supplied to said facility,
first sensing means communicating with said duct means for sensing the air supply flow rate therewithin and producing a first pneumatic signal representative thereof,
second sensing means communicating with said duct means for sensing the static duct pressure therewithin as corresponding to the discharge pressure of said supply blower and producing a second pneumatic signal representative thereof,
a proportional plus reset controller,
means for transmitting the first pneumatic signal to said proportional plus reset controller as a set point signal, and for transmitting the second pneumatic signal to said proportional reset controller as a feedback signal,
said transmitting means including tuning means for adjusting said first and second pneumatic signals in accordance with a predetermined desired relationship of the discharge pressure of said supply blower and the supply flow rate,
said proportional plus reset controller being operable to produce a pneumatic output control signal dependent on the difference between the feedback pneumatic signal and the set point pneumatic signal, and
adjustment means responsive to the pneumatic output control signal of said proportional plus reset controller for adjusting the output of said supply blower to establish said desired relationship of the discharge pressure of said supply blower with respect to the supply flow rate.

6 more elements

a supply blower,
duct means connected to said supply blower for receiving and conveying an air supply flow from said supply blower to air conditioning means, the air as conditioned therein being supplied to said facility,
first sensing means communicating with said duct means for sensing the air supply flow rate therewithin and producing a first signal representative thereof,
second sensing means communicating with said duct means for sensing the static duct pressure therewithin as corresponding to the discharge pressure of said supply blower and producing a second signal representative thereof,
first and second transmitting means operably coupled to said first and second sensing means for transmitting the signals produced thereby, said first and second transmitting means including tuning means for adjusting said first and second signals in accordance with a predetermined desired relationship of the supply flow rate and the discharge pressure of said supply blower,
a control system responsive to said supply flow rate and pressure adjusted signals to generate an output control signal, and
adjustment means responsive to the output control signal for adjusting the output of said supply blower to establish said desired relationship of the discharge pressure of said supply blower with respect to the supply flow rate.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 05/528,590Filed 29 Nov 1974 · continuation
Priority: 22 Jun 1972
Granted: 15 Mar 1977
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

F04D 27/003
Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids: by throttling
F24F 11/89
Control or safety arrangements: arrangement or mounting of control or safety devices
F04D
Non-positive-displacement pumps
F24F
Air-conditioning