Pumps – One fluid pumped by contact or entrainment with another – Jet
Reexamination Certificate
1999-09-27
2001-08-21
Tyler, Cheryl J. (Department: 3746)
Pumps
One fluid pumped by contact or entrainment with another
Jet
C417S176000
Reexamination Certificate
active
06276903
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention pertains to the field of jet technology, primarily to jet devices for producing a vacuum and for evacuation of various gaseous and gas-vapor mediums. The invention is applicable in various industrial processes, for example for the vacuum distillation of oil stock in rectifying columns.
A liquid-gas ejector is known, which has a nozzle, a receiving chamber, a mixing chamber and a diffuser (see, for example, SU, Certificate of authorship, 1305445, cl. P 04 F 5/04).
This jet device has a complicated design, that results in high specific consumption of materials. It also has a relatively low efficiency factor.
The closest analogue of the ejector introduced in the present invention is a liquid-gas jet ejector having a distribution chamber with nozzles, a receiving chamber, a mixing chamber and a discharge chamber, wherein each mixing chamber is placed in alignment with its nozzle (see Sokolov E. Y. and Zinger N. M. Jet apparatus, M., Energy 1970, page 228-229).
The given liquid-gas ejector can provide evacuation of gaseous and gas-vapor mediums, however it has a relatively low efficiency factor since the geometry of its elements is nonoptimal and unsuitable for simultaneous evacuation of gas-vapor mediums and generation of a vacuum in the evacuated reservoir.
SUMMARY OF THE INVENTION
The present invention is aimed at increasing the efficiency factor of a liquid-gas ejector through optimization of the geometry of the ejector's elements, specifically the ejector's mixing chambers.
The stated problem is settled as follows: a liquid-gas ejector, which has a distribution chamber with nozzles, a receiving chamber, a discharge chamber and mixing chambers and wherein each mixing chamber is composed of a cylindrical inlet section, a convergent intermediate section and a cylindrical outlet section and is placed in alignment with the corresponding nozzle, has mixing chambers with the following geometrical parameters: the ratio of the cross-sectional area of the inlet cylindrical section of the mixing chamber to the cross-sectional area of the outlet cylindrical section of the mixing chamber is from 0.5 to 50.0; the length of the inlet cylindrical section of the mixing chamber represents from 0.05 to 36 times D
K
, the length of the intermediate convergent section of the mixing chamber represents from 0.02 to 50 times D
K
and the length of the outlet cylindrical section of the mixing chamber represents from 0.5 to 220 times D
K
, where D
K
is the diameter of the outlet cylindrical section of the mixing chamber.
Additionally, each mixing chamber can be furnished with a conical guide duct, converging in the flow direction. The taper angle of the duct is from 1.89° to 45°, the length of the duct represents from 0.02 to 26.0 times D
K
, where D
K
is the diameter of the outlet cylindrical section of the mixing chamber. At the same time, the intermediate convergent section of the mixing chamber can be formed with a conical surface. The angle of inclination of this conical surface from the longitudinal axis of the mixing chamber is from 0.10 to 780.
Experimental research has shown, that the profile of the flow-through canal of the mixing chamber exerts significant influence on the efficiency factor of the liquid-gas ejector. It is known, that a homogeneous gas-liquid mixture can be formed in a mixing chamber, whose length represents from 40 to 50 times the mixing chamber's diameter (for cylindrical mixing chambers), however the stated parameters are effective in a narrow range of the ratio of the cross-sectional area of the mixing chamber to the cross-sectional area of the nozzle's outflow face.
The research has shown, that in the case of evacuation of a gas-vapor medium containing components, which can be condensed during mixing with a liquid ejecting medium, it is not advisable to use a uniform cylindrical mixing chamber. It was determined, that in this case the mixing chamber should be composed of a cylindrical inlet section, a convergent intermediate section and a cylindrical outlet section. For such, an optimal correlation of dimensions of the sections of the described shaped mixing chamber is quite important. It was ascertained that the ratio of the cross-sectional area of the inlet cylindrical section of the mixing chamber to the cross-sectional area of the outlet cylindrical section of the mixing chamber should be from 0.5 to 50.0; the length of the inlet cylindrical section of the mixing chamber, the length of the intermediate convergent section of the mixing chamber and the length of the outlet cylindrical section of the mixing chamber should represent respectively from 0.05 to 36 times, from 0.02 to 50 times and from 0.5 to 220 times the diameter of the outlet cylindrical section of the mixing chamber.
Additionally, in a number of cases, subject to the type of ejecting medium, being fed into the ejector's nozzle, the mixing chamber can be furnished with an inlet guide duct, particularly with a conical guide duct, converging in the flow direction. Subject to the density of the ejecting medium, and further subject to the dispersion ability of the ejecting medium, the taper angle of the inlet guide duct can be from 1.89° to 45° and the length of the duct can represent from 0.02 to 26.0 times the diameter of the outlet cylindrical section of the mixing chamber.
In addition to the above stated correlations between the lengths of the mixing chamber's sections and their cross-sectional areas, the angle of inclination of the conical surface forming the chamber's intermediate convergent section to the longitudinal axis of the mixing chamber can influence the mixing chamber's operation. Subject to the type of ejecting medium, to the nature of the evacuated gaseous medium and to the content of components, which can be condensed in the ejecting medium, in the evacuated medium, the angle of inclination of the conical surface forming the intermediate convergent section to the longitudinal axis of the mixing chamber can be from 0.1° to 78°.
A liquid-gas ejector of the introduced design has an increased efficiency factor.
REFERENCES:
patent: 2378425 (1945-06-01), Murray
patent: 2582069 (1952-01-01), Rose
patent: 5628623 (1997-05-01), Skaggs
patent: 1120-115 A (1984-10-01), None
patent: 112242 (1958-12-01), None
patent: 1054580 (1983-11-01), None
patent: 1291730 (1987-02-01), None
patent: 1305445 (1987-04-01), None
Sokolov E.Y., “Jet apparatuses” book, 1970, USSR, Moscow, “Energy” Publishing house, p. 229.
Oathout Mark A.
Petroukhine Evgueni D.
Tyler Cheryl J.
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