Liquid heaters and vaporizers – Circulation – Injector
Patent
1985-10-02
1986-09-02
Favors, Edward G.
Liquid heaters and vaporizers
Circulation
Injector
122442, F22D 100, F22D 704
Patent
active
046089454
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE ART
The invention relates to the manufacture of boilers for thermal power plants, and in particular, it deals with an apparatus for recirculating boiler fluid in thermal power plants in which it is necessary to increase flow rates or temperature of boiler fluid in various circulation circuits.
State of the Art
An apparatus for recirculating boiler fluid in oncethrough boilers is known (U.S. Pat. No. 3,411,485, Int. Cl..sup.3 F 22 B 35/10; US Cl. 122-407, published in 1968), in which, to increase the flow rate of fluid in the furnace screens of the boiler, use is made of a jet pump installed downstream the feed valve of the boiler. The apparatus also comprises a pipeline for recirculation of boiler fluid connecting a moisture separator to the suction pipe of the jet pump.
This apparatus for recirculating boiler fluid is, however, only operable in a narrow range of steam loads of the boiler since with such an arrangement of the feed valve and jet pump it is not possible to match the hydraulic characteristic of the boiler duct to the pressure characteristic of the jet pump.
For instance, if the jet pump having a high-pressure characteristic is used, the apparatus for recirculating fluid can only function under high boiler loads, and if the jet pump with a low-pressure characteristic is used, the recirculation apparatus will only function under start-up and low loads which is the field of application of this prior art apparatus.
An apparatus for recirculating boiler fluid is also known (U.S. Pat. No. 3,478,726, US Cl. 122-406, Int.Cl..sup.3 F 22 B 35/10, published in 1968), which is used in a oncethrough combined circulation boiler, comprising a controlled jet pump and a feed valve which are connected in series with a feedwater pipeline, and also a recirculation pipeline connecting a separatot to the jet pump. The jet pump has a chamber of static pressure in which is installed an axially movable hollow cylindrical member having one end secured to a movable rod and the other, free end provided with a nozzle. The recirculated fluid is fed from the separator through the recirculation pipeline to the interior of the cylindrical member, and feedwater, which is the working fluid of the pump, is fed into an annular space between the nozzle and the walls of the jet pump from an economizer. During axial displacement of the hollow cylindrical member, the cross-section of the annular space changes thereby ensuring a change in the flow of working fluid supplied to the mixing chamber of the jet pump to which the recirculated fluid is also supplied through the nozzle of the hollow cylindrical member. Then pressure is restored and velocities of fluids in the flow duct of the jet pump are equalized, and a mixture of the working and recirculated fluids is supplied therefrom to the furnace screens of the boiler.
In the known apparatus for recirculating boiler fluid, the jet pump is used as both pumping device and a feed valve of the boiler under normal operating conditions, and the feed valve proper is only actuated under emergency conditions or in case the pump fails.
The supply of working fluid effected as described above results in energy losses for eddy currents in the mixing chamber downstream the annular space, such losses occurring over the whole range of the boiler loads since there no means for controlling flow rate of feedwater under normal operating conditions other than the jet pump.
In addition, with the employment of this known apparatus high enough flow of recirculated fluid (with recirculation ratio of about 2-3) required at low boiler loads cannot be achieved since additional pressure losses occur if high flows pass through the nozzle orifice. All these factors result in a low efficiency of the apparatus for recirculating fluid in a once-through boiler.
SUMMARY OF THE INVENTION
The invention is based on the problem of providing an apparatus for recirculating boiler fluid having such a construction of a jet pump and its hollow cylindrical member and such a supply of working and recirculated f
REFERENCES:
patent: 2614543 (1952-10-01), Hood
patent: 3101699 (1963-08-01), Vorkauf
patent: 3411485 (1968-11-01), Kraus
patent: 3478726 (1969-11-01), Kikinis
patent: 3789806 (1974-02-01), Gorzegno
patent: 4151813 (1979-05-01), Gorzegno et al.
patent: 4183331 (1980-01-01), Hull
Favors Edward G.
Vsesojuzny Nauchno-Issledovatelsky Institut Atomnogo Energetiche
LandOfFree
Apparatus for recirculating boiler fluid does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for recirculating boiler fluid, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for recirculating boiler fluid will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1092072