US 2759661 A
Description (OCR text may contain errors)
Aug. 21, 1956 G. NGLLER ETAL 2,759,661
VAPOR EJECTOR PUMPS Filed April 12, 1952 Fig-7 14' 15 1a 19 17 21 F ig.2 15
34 Fig.3C 3g lNVEN TOR s HANS GEO/Q6 NOlLE/Q AND G'J/VTSQ REI'CH United States Patent VAPOR EJECTOR PUIVIPS Hans Georg Niiller, Koln-Sulz, and Giinter Reich, Bad Godesberg, Germany Application April 12, 1952, Serial No. 282,068
6 Claims. (Cl. 230-95) The invention relates to vapor ejector pumps using any desired liquid as driving medium, especially pumps having a straight or converging hollow body arranged in front of the jet at a predetermined distance around the vapor spout and over a predetermined distance along that vapor spout to permit dilfusion or predetermined expansion of the vapor passing the jet, thereby producing a vacuum in the space surrounding the jet, regardless whether in the pump a spout of vapor of water, of mercury or oil is formed.
Such pumps have been found to show during operation instabilities in the adjusted pressure value. Experiments underlying this invention have shown that these instabilities result from the fact that the cross-section of the spout within the ditfusor varies, narrowing down depending upon varying suction pressure, i. e. the pressure in the recipient to be evacuated.
As a result, between the vapor spout and the inner wall of the diffuser there is formed a ring-shaped slit through which air, gas or vapor can return into the recipient to be evacuated.
It is therefore an object of the invention to provide in a straight or cylindrical difiusor, guiding plates or surfaces which intersect at an angle a plane perpendicular to the axis of the diifusor.
Such guiding surfaces counteract variation in the free cross-section of the spout due to varying suction pressure. As a result, the above mentioned slit will be reduced, if not avoided.
These and other objects of the invention will be more fully described in the drawing annexed herewith, in which Fig. 1 shows in section an example of realizing the invention as applied to a simple vapor ejector pump;
Fig. 2 shows another form of guiding surfaces, viewed in the direction of arrows of Fig. l and in a direction perpendicular to the view of Fig. 1;
Fig. 3a represents another type of guiding surfaces, also viewed in direction of arrows 10 of Fig. 1;
Figs. 3b and 30 represent side views of certain guiding surfaces shown in Figs. 3a.
In Fig. 1, 11 designates in section a driving jet, to which over line 12 in direction of arrow 13, driving vapor from a boiler (not shown) is supplied. Driving jet 11 is arranged in the interior of a tube 14 shaped partly conically and partly cylindrically. Tube 14 is connected to a recipient (not shown) to be evacuated.
The conical portion 14' of tube 14 is connected to difiusor 15 which is shaped convergent in the direction of the current of the driving vapor. In the interior of diffusor 15, there are arranged two concentric tubes 16, 17 of varying length, 16 being shown in section and 17 in full. Tube 16 is attached to the inner wall of diffuser 15 by means of radial wires 18. Similarly, tube 17 is connected by means of radial metal strips 19 to the inner wall of diffusor 15.
Diffusor 15 is arranged inside of vessel 20, also shown in section. Vessel 20 consists of a cylindrical portion 21 having an end wall 22. Inside of vessel 21, 22, there 2,759,661 Patented Aug. 21, 1956 "ice is arranged another substantially cylindrical vessel 23 into which the small end of diifusor 15 extends. The space between the inner surface of cylinder 21 and the outer surface of cylinder 23 is connected to an outlet tube 24. Box 25 diagrammatically represents a condenser of otherwise well known construction which is supplied with circulating cooling water used for the condensation of the driving vapor. Line 26 serves to return the condensed driving medium in direction of arrow 27 into the boiler.
Tubes 16 and 17 counteract the transversal movement of the vapor spout within diifusor 15 so that the above mentioned instabilities can not occur anymore.
In Fig. 2 the guiding surfaces are shown to consist of a series of parallel plates 28-31 which are also parallel to the axis of the diffusor. Plates 2831 are attached to the inner surface of the dilfusor, for example by weldmg.
In the modification of 3a, the guiding surfaces are formed in two sets of plates, a vertical set 32-36 and a horizontal set 3731. Vertical as well as horizontal plates are attached to the inner wall of dilfusor tube 15 in any appropriate manner, for example by welding.
Figs. 3b and 30 show in more detail one of the vertical and horizontal plates 34 and 39, respectively. Both types of plates are of generally trapezoidal shape. Vertical plate 34, Fig. 3b, has slits 42-46 extending from the two oblique edges and the small base of the trapezium into vertical direction to the top Horizontal plate 39, Fig. 30, has slots 47-51 extending from the large base of the trapezium vertically to the bottom. Slots of Figs. 3b and 3c are of different length, as shown.
The plates of Fig. 3b and 3c are slidable one into the other in such a manner that a plate, such as shown in Fig. 30, will he slid from the bottom into a plate, such as shown in Fig. 3b, in such a manner that the planes of the two types of plates will be arranged perpendicular to each other.
The description shows that plates 34 and 39, as well as the other plates, i. e. vertical plates 32, 33, 35, 36 and horizontal plates 37, 38, 40, 41 should be constructed in such a manner that they can be assembled with central plates 34 and 39 to an arrangement of guiding surfaces similar to that shown in Fig. 30.
1. In a vapor ejector pump, a jet for passing a vapor spout to produce a vacuum in space surrounding the jet, said space being defined by a conical tube coaxial with and surrounding said jet; with a gradually increasing diameter from a point behind the opening of said jet to a point in front of the opening of said jet, thereby causing diffusion of said spout; said conical tube having at its small end an input tube to be connected to the space to be evacuated, and having connected at its large end an output tube; and dividing members supported in said output tube in the path of said spout and extending substantially in a direction parallel to the axis of said jet so as to permit passage of vapor with at least a reduction in transversal motion of the vapor particles.
2. Pump according to claim 1, wherein said dividing members are in the form of concentric tubes having an axis substantially coinciding with the axis of said jet.
3. Pump according to claim 1, wherein said output tube is a conical tube, said conical tube extending with gradually decreasing diameter from the front opening of the first tube in the direction of the axis of said jet and coaxially therewith.
4. Pump according to claim 3, wherein said dividing members are in the form of spaced parallel plates, arranged substantially in a direction parallel to the axis of said jet.
5. Pump according to claim 3, wherein said dividing 3 members are in the form of two sets of sheets, each set having spaced parallel spaced elements, which are also parallel to the axis of said jet.
6. Pump according to claim 5 wherein said two sets of sheets are arranged to penetrate each other at right 5 angles and are of substantially trepzoidal shape, each having a number of longitudinal slots permitting the elements of said two sets to penetrate each other, thereby subdividing the cross section of said spout into a number of quadrangular longitudinal channels extending in a 10 direction parallel to the axis of said jet.
UNITED STATES PATENTS Bills May 24, Boeing June 18, Ehrhart Feb. 6, Lamn Mar. 12, Hickman Aug. 20,