US1437819A - Ejector - Google Patents

Description

H. F. SCHMIDT.

EJECTOR.

APPLICATION FILED SEPT. 11, 1920.

1 437,81 9 Patented Dec. 5, 1922.

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IN VEN TOR.

H. F. Schmidt A TTORNEY Patented Dec. 5, 1922.

UNITED STATES PATENT OFFICE.

ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

EJECTOR.

Application filed September 11, 1920. Serial No. 409,613.

To all whom it may concern:

Be it known that I, HENRY F. SCHMIDT, a citizen of the United States, and a resident of Swarthmore, in the county of Delaware and State of Pennsylvania, have invented a new and useful Improvement in Ejectors, of which the following is a specification.

My invention relates to ejectors, and more particularly to that type known as hotwell e'ectors and employed to remove the conensate from the hotwells of surface condensers.

The object of my invention is to provide a multi-stage hotwell ejector which shall have one or all of the overflows connected to a source of very low pressure, prefer' ably the surface condenser from which the condensate is being removed. A further object is to provide a device which shall operate on a low pressure fluid supply, maintain a positive and continuous operation and create a high vacuum within the condenser to which it is attached.

I attain these objects by means of the system shown in the accompanying drawing, in which the View is a diagrammatic illustration of my invention.

Referring to the drawing for a more detailed description of my invention, 10 indicates a surface condenser which dis-.

charges the condensate into the hotwell 11 at the bottom of the condenser. The condensate is removed from the hotwell by means of a multi-stage hotwell ejector and in this case I have shown a two-stage ejector. The first-stage ejector 12 is operated either by the exhaust steam from partially condensing power units or by live steam which is supplied through the conduit 13. The steam is expanded through the nozzle 14 into the receiving or mixing chamber 15 where it combines with the condensate from the hotwell, the resultant mixture being discharged through the diffuser 16 into the chamber 17 of the second-sta e ejector 18.

The second-stage ejector ikewise is operated either by exhaust steam from partially condensing ower units, by live steam which is supplie through the conduit 19, or other source of low-pressure supply. The steam is expanded through the nozzle 20 into the receiving or mixing chamber 21 where it combines with the condensate from. the chamber 17, the resultant mixture being discharged through the diffuser 22 into the discharge conduit 23. The discharge condult 23 1s provided with a check valve 24: to prevent back flow into the ejector due to the pressure of the atmosphere.

The first-stage ejector 12 is provided w1th an overflow 30, and in a similar way the second-stage ejector 18 is provided with an overflow 31. The two overflows are connected by means of the conduit 32 which in turn discharges through the conduit 33 into the condenser, the steam thereby being condensed.

The vacuum maintained in the shell and hotwell of a surface condenser is generally about 28 inches of mercury, or the pressure existing therein about one pound absolute. As the. condensate is ordinarily discharged into the feed-water heater, and as the pressure in the heater is usually atmospheric, some means must be employed to overcome this difference of pressure. This is accom plished by means of a hotwell ejector in which the steam expanding through a nozzle acquires a high velocity and entrains the condensate and any other vapors mixed therewith, the resulting mixture having a sufiiciently high velocity to discharge against the higher pressure. It has been fully demonstrated that it is not always possible to discharge against. a high pressure by means of a single stage ejector, that is, an ejector in which the one or more nozzles discharge into a single mixing chamber. For this reason it is frequently necessary to design an ejector with aseries of stages, each stage increasing the velocity of the condensate until the condensate receives a velocity sufficient to discharge against the higher pressure. In the drawing the hotwell ejector is shown as composed of two stages, but it is the purpose of the invention to employ a hotwell ejector comprising any number of stages sufficient to discharge the condensate at much higher pressure than that at which it is received in the hotwell.

The operation of my improved multista e ejector is as follows: When the steam is rst turned on, the condensate will not receive a sufficient velocity to discharge against the higher pressure within the feed water heater or other receptacle which is usually at atmospheric pressure. It will, therefore, be necessary to provide overflows at the several stages in the ejector so that the condensate will be taken care of until it receives a suflicient velocity to discharge against the higher pressure maintained within the feed water heater. The check valve Ql is held closed by atmospheric pres-.

sure until the motive fluid has attained sufficicnt pressure to discharge the condensate in any convenient receptacle 23 where the pressure is atmospheric while the pressure in the condenser 10 is usually about one pound absolute.

In the drawing, the overflows are shown connected to the condenser so that the overflow steam will be condensed by passage through the condenser. It will thus be seen that in my unique arrangement of parts, I have an ejector in which a low pressure motive fluid is used to discharge the condensate at a higher pressure, which shall have a minimum of moving parts and maintain a positive and continuous operation.

lVhile I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specific-ally set forth in the appended claims.

Vhat I claim is 1. In combination with a surface condenser, a multi-stage ejector, an over-flow chamber for each stage, and means connecting said chambers to the condenser.

2. In combination with a surface condenser, an ejector comprising a series of stages, an overflow chamber at the discharge end of each stage, and means to conduct the overflow to the top portion of the condenser.

3. In combination with a surface condenser, a tandem ejector device operating on low pressure motive fluid and adapted to receive condensate at low pressure from the condenser and discharge it at higher pressure, comprising a series of motive fluid sup ply nozzles, mixing chambers, an overflow chamber at the discharge of each mixing chamber, and an overflow conduit connecting said overflow chambers and the-top portion of the condenser.

4. A condensate ejector comprising a plurality of stages provided with overflows and arranged in series, the diffuser of the fir'st stage dischargin into the receiving chamber of the succee ing stage and the last stage having a nozzle for the admission of lowpressure motive fluid.

5. In an ejector device, in combination, a plurality of stages each comprising a fluid supply nozzle, a mixing chamber and an over-flow chamber, and means connecting said overflow chambers to a region of low' pressure.

6. In combination with a condenser, a condensate ejector comprising a receiving chamber communicating with the bottom portion of the condenser, a mixing cone extending within the receiving chamber, a motive-fluid nozzle arranged to discharge into said mixing cone, an overflow chamber communicating with the mixing cone, a diffuser extending within the overflow chamber and adapted to receive the discharge from the mixing cone, a second receiving chamber communicating with said diffuser, a second mixing cone extending within the second receiving chamber, a second motive fluid nozzle arranged to discharge into the second mixing cone, asecond overflow chamber in communication with the second mixing cone, a second diffuser extending within the second overflow chamber and arranged to receive the discharge of the second mixing cone, and connections affording communication between the overflow chambers and the upper portion of the condenser.

7. In combination with a condenser, a plurality of condensate ejector-s arranged in series and communicating with the condenser, overflow chambers communicating with the ejectors, and connections affording communication between the overflow chambers and the upper portion of the condenser.

In testimony whereof, I have hereunto subscribed my name this 8th day of September, 1920.

HENRY F. SCHMIDT.

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