US2231090A - Ejector - Google Patents

Description

E. G. ROSS EJECTOR Feb. l1, 1941.

'Filed April 14, 1939 3 Sheets-Sheet 1 w9sY/67-M l. all

Emea G. 'R055 l ENToR ATTORNEY Feb. 11, 1941. E, G, Ross 2,231,090

EJECTOR Filed April 14, 1959 3 SheefS-Sheet 3 ATTORNEY u Patented Feb. 11, 1941 UNITED STATES PATENT; OFFICE EJEcroa Application April 14, 1939, Serial N o. 267,936

18 Claims.

This invention relates to ejectors, preferably I of the steam' jet type, operating at exceedingly high vacuums or at low absolute pressures.

During the operation of steam jet ejectors, when operating at low absolute pressures such as ls than LV2 mm., or when handling a gas that will freeze at relatively low pressures and temperatures, ice forms on the inside of the steam nozzle and/or on the inside of the diffuser, choking the passageways and interfering with the efficiency of the ejectors.

An object of the present invention is to provide means for heating the nozzle or diffuser or both, as conditions may require, to prevent the4 formation ofsueh ice and the consequent reduction of the efficiency of the ejectors.

With these and other objects in view, as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which Will be rst described in connection with the accompanying .,drawings, showing an ejector of the preferred form embodying the invention, and the features forming the invention will be specifically pointed out in the claims.

In the drawings: Figure 1 is a longitudinal section through an ejector constructed in accordance with ther present invention.

Figure 2 is a cross-section taken on the line 2 2 of Figure 1.

Figure 3 is a cross-section taken on the line 3 3 of Figure 1.

Figure 4 isa longitudinal section through a modied form of the invention.

Figure 5 is a cross-section on the line 5-5 of Figure 4. y

Figure 6 is a fragmentary section of a, further modied form of the invention, being a modiilca- 40 tion of the structure shown in Figures 4 and 5.

' Figure '1 is a longitudinal section through a still Afurther modified form of the ejector and its heating means.

Referring more particularly to the drawings, and with particular reference to the preferred form of the invention shown in Figures 1 to 3 inclusive, the ejector comprises the diffuser body I having the nozzle head 2 attached thereto in any suitable manner, and the nozzle head 2 has therein which opens into the inlet of the diffuser the diffuser in the usual manner. The nozzle the air or gas inlet ongsuction passage 3 formed structure 6 includes the nozzle 1, which is de- -tachably connected in any suitable manner, as shown at 8, to the steam inlet connection 9, which may or may not have an inlet chamber I0 therein, as desired. The steam employed for operating 5 the ejector comes from any suitable source (not shown)` through the steam inlet II and passes through the diverging bore I2 of the nozzle 1 into the diffuser 4.

Ejectors operating atlowfabsolute pressures, 1o such as less than 41/2 mm. or handling a gas that will freeze at relativelylow pressures and temperatures, have been found subject to impairment of their eiliciency by the formation of ice in the bore I2 of the nozzle 1 near its outlet 15 and/or in the diverging. converging bore I 2 of the diffuser 4. To prevent the formation of such ice, the present inventionembodies means for heating the nozzle 1 'and/or the diffuser 4. p

In the structure shown in Figures 1 to 3 of the 20 drawings, a heating jacket I4 is formed about the nozzle 1 providing a chamber I5 which has communication with the steam inlet of the nozzle 1 through a passage I6, so that live steam entering the chamber I0 or the inlet passage of the ejector 25 will pass through the passage I6 into the chamber I5 and have direct contact with the exterior of the nozzle 1 for heating it to prevent the accumulation of ice on its inner surface or the walls of the bore I2. The steam circulates through the 30 chamber I5 and passes therefrom through an outlet passage I1. In Figure 1 of the drawings the outlet passage I1 is connected by a pipe I8 with the heating or steam chamber I9 which surrounds the diiuser 4. Ihe chamber I9 is formed 35 between the diffuser 4 and the jacket-forming, `diiixliser-carrying jacket 20. The chamber I9 has an outlet 2| for the steam which may be opened to atmosphere or may be connected to anv desired point. 40

If it is so desired, the outlet I1 may open directly to atmosphere or to any other suitable point, and a separate pipe, as indicated in dotted lines at 22, may have direct connection with the steam supply pipe 23 and the steam inlet 24 of 45 the chamber I9. A

In the modied form of the invention shown in Figures 4 and 5 of the drawings the nozzle 1' is heated by means of a steam coil 3B, which is coiled about the nozzle in contact therewith, and 50 is enclosed in the heating chamber 3| formed within the jacket I4'. The inlet end of the coil 30 opens into the chamber or steam inlet passage I0', so that live steam from the steam inlet will be delivered directly into the coil. The outlet end 55 of the coil is connected to the passage Il', which may be open to atmosphere, or as shown in Figure 4, may be connected to the inlet end of the coil 33. The coil 33 is coiled about and contacts the outer wall of the diffuser 4', and is enclosed within the heating chamber I9 formed about the diffuser 4 by the jacket 20'. The outlet of the coil 33 is preferably at the lower end of the chamber i9', as shown at 34.

As in the form of the invention shown in Figures 1 to 3 inclusive, the coil 33 may receive its steam direct from the steam inlet pipe ,23' through a pipe connection such as the dotted line connection 22', at which time of course the outlet I'I'hof the coil 30 will not be connected to the inlet of the coil 3 3 by means of the pipe I8'.

Figure 6 of the drawings shows a construction which is similar to the upper half or nozzle heating part of the structure shown in Figure 4, including a coil 36, which is coiled about the nozzle 1a, in contact therewith, for heating the nozzle to prevent formation of ice on the nozzle. Unlike the structure shown in Figure 4, however, the inlet of the coil 36 is shown as passing out through the head 2a, and it has connection with any suitable supply (not shown) of a heating medium, which may be steam, hot water, or any available and suitable medium for imparting the necessary heat to the nozzle 1a to prevent the formation of ice therein. A similar arrangement may be employed in connection with the coil 33 shown in Figure 4 by merely connecting the pipe 22' to any suitable source of heating medium other than to the steam supply 23', without departing from the spirit of the present invention.

Figure '1 shows a still further modification of the means of heating the nozzle and/or the diffuser of the ejector. In this modified form an electrical heating coil 40 is coiled about the nozzle 1b and a second heating coil 4I is coiled about and in contact with the diffuser 4b. These coils 40 and 4| may be of any approved type of electrical heating coil, and they are enclosed in suitable jackets I4b and 20h to prevent their engagement with the steam, air and/or gas passing through the ejector. The energizing of the coils 40 and 4I may be through any suitable medium,

and the coils may be' simultaneously energized,

such as by the closing of a single switch as indicated in solid lines at 42, or they may be independently energized by independent switches and circuits, as shown in dotted lines at 43 and 44.

From the foregoing description taken in connection with the accompanying drawings it will be apparent that various types of heating means widely modified within the invention defined by I the claims. v

ejector is operating at low absolute pressures the inlets of said steam jackets receiving steam independently from the steam entering the inlet of the ejector.

2. In an ejector, a nozzle; a diffuser, a steam jacket about said nozzle having an inlet and an outlet for heating steam, and a steam jacket about said diffuser having inlet for steam whereby said nozzle and diffuser may be heated to prevent formation of ice therein when the ejector is operating at low absolute pressures, the outlet of said nozzle enclosing steam jacket being connected to the inlet of the diffuser enclosing steam jacket.

3. In an ejector, a nozzle, said ejector comprising an inlet passage for steam'to said nozzle, a steam jacket about said nozzle v'having an inlet for steam opening into said steam inlet passage whereby the nozzle may be heated to prevent formation of ice therein when the ejector is 0perating at low absolute pressures said jacket having a steam outlet opening out independently o the steam passages of the ejector.

4. The method of preventing lowering of the eiliciency of an ejector operating at low absolute pressures by the formation of ice Within the ejector which consists in applying heat to the parts of the ejector subject to excessive cooling action when the back pressure in the ejector is reduced below the ice point.

5. The method of preventing lowering of the efficiency of an ejector operating at absolute pressures equal to or lower than four and one-half millimeters (4l/ mm.) by formation of ice withinv the ejector which consists in utilizing part of the operating steam delivered to the ejector as a heating medium to heat the parts of the ejector subject to excessive cooling action when the back pressure in the ejector is reduced sufficiently to permit formation of ice in the ejector.

6. The method of preventing lowering of einciency of an ejector operating at low absolute pressures by the formation of ice within the ejector which consists in utilizing part of the operating steam delivered to the ejector as a heating medium to heat the surfaces of the ejector swept by the steam.

7. The method of preventing lowering of the efficiency of an ejector operating at low absolute pressures by the formation of ice within the ejector which consists in utilizing part of the operating steam delivered to the ejector as a heating medium to heat the nozzle of the ejector and subsequently utilizing the nozzle heating steam to heat the diffuser of the ejector structure.

8. In an ejector, means to prevent the formation of ice on the surfaces of the ejector swept by operating steam when the ejector is operating at absolute pressures lower than four and onehalf millimeters (4l/2 mm.) said means comprising steam jackets about the steam swept surfaces and having connection with the steam supply ofthe ejector, said jackets connected in series whereby the steam will pass successively from one jacket to the next in the series.

9. The combination with an ejector including a steam nozzle and a diffuser, of means to prevent the formation of ice on the surfaces of the ejector swept by the operating steam when the elector is operating at absolute pressures lower than fur and one-half millimeters (4l/2 mm.), said means carried by the ejector and arranged to deliver heat to the steam swept surfaces.

10. The combination with an ejector including a steam nozzle and a diffuser, of means to. prevent the formation of ice on the surfaces of the ejector swept by the operating steam when the ejector is operating at low absolute pressure, said means comprising means for delivering heat from a source other than the steam passing through the nozzle and diffuser to the surfaces swept by the steam fiowing through the nozzle and diffuser.

1l. The method of preventing lowering of the efficiency of an ejector operating at low absolute pressures by formation of ice Within the ejector which consists in circulating part of the operating steam of the ejector about the exterior surfaces of the parts of the ejector subject to excessive cooling action when the back pressure in the ejector is reduced sufliciently to permit formation of ice.

12. In an ejector, a nozzle, a diffuser, means to prevent the formation of ice in the ejector when the ejector -is operated at low absolute pressure comprising a jacket about said nozzle, and means within said jacket for heating the nozzle to counteract the chilling thereof effected by the 10W pressure operation of the ejector.

13. In an ejector, a nozzle, a diffuser, means to prevent the formation of ice in the ejector when the ejector is operated at low absolute pressure comprising a jacket about said nozzle, means within said jacket for heating the nozzle to counteract the chilling thereof effected by the low pressure operation of the ejector, and a second jacket about the diffuser, and heating means Within the jacket surrounding the diffuser for heating the diffuser to counteract the chilling thereof effected by the low pressure operation of the ejector.

14. The combination with an ejector including a steam nozzle and a diffuser, of means to prevent the formation of ice on the surfaces of the ejector swept by the operating steam when the ejector is operating at low absolute pressure, said means comprising heating coils coiled about said nozzle and diffuser for delivering heat to the surfaces swept by the steam flowing through the nozzle and diffuser, said heating coils connected in series to permit flow of a heating medium from one coil to the other.

15. The combination with an ejector including a steam nozzle and a diffuser, of means to prevent the formation of ice in the ejector when the ejector is operating at low absolute pressures, said means comprising electrical heating coils coiled about said nozzle and diffuser for heating the parts of the ejector subject to excessive cooling action when the back pressure in the ejector is reduced sufhciently to permit formation of ice.

16. The combination with an ejector including a steam nozzle and a diffuser, of means to pre vent the formation of ice within the ejector, said means including electrically operated heating means about the nozzle for heating the nozzle when the back pressure in the ejector is reduced sufficiently to permit the formation of ice.

17. The combination with an ejector including a steam nozzle and a diffuser, of means to prevent the formation of ice within the ejector, said means comprising electrically operated heating means about the nozzle and the diuser for heating the nozzle and the diffuser and prevent the formation of ice in the ejector when the back pressure in the ejector is reduced sufficiently to permit the formation of ice.

18. The combination with an ejector including a steam nozzle and a diffuser, of means to prevent the formation of ice in the ejector, said means comprising steam coils coiled about the nozzle and about the diffuser for delivering heat to the nozzle and the diffuser to prevent the formation of ice when the back pressure in the ejector is reduced sufficiently to permit the formation of ice therein.

- ELMER G. ROSS.

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