US1122733A - Exhaust-nozzle. - Google Patents

Description

P. A. GOODPELLOW.

EXHAUST NOZZLE.

APPLICATION FILED SEPT. s, 1913.

Patented Dec. 29, 1914.

2 SHEETS-SHEET 1.

INVENTOH WITNESSES dra g/ A I M fix-M4 F. A. GOODFELLOW.

EXHAUST NOZZLE.

APPLICATION FILED SBPT.6,'1913 Patented Dec. 29, 1914.

2 SHEETSSHEET 2.

WITNESSES UNITED STATES PATENT OFFICE.

FRANK A. GOODFELLOW, OF ALTOQNA, PENNSYLVANIA,

EXHAUST-NOZZLE.

Specification of Letters Patent.

Patented Dec. 29, 1914.

Application filed September 6, 1913. Serial No. 788,494.

and useful Improvements in EXhaust-Noz zles, of which the following is a specification.

The invention relates to exhaust nozzles for locomotives and has for itsprimary objects; the provision of a nozzle adapted to break up the body of steam somewhat and secure a better entrainment of the gases in the smokebox but without decreasing the .velocity of the body of steam; the provision of a nozzle which will reduce the back pressure in the cylinders; the provision of a nozzle whereby the draft and consequently the capacity of the boiler is increased, and the provision of a nozzle which can be cheaply constructed with a minimum amount of machine work. One embodiment of the invention is shown in preferred form in the accompanying drawings, wherein- Fig. l is a plan view of my improved nozzle, Fig. 2 is a section on the line IIII of Fig. 1, Fig. 3 is a side elevation of a portion of the end of the locomotive, and showing the relative arrangement of the nozzle, petticoat pipe, and stack, and Figs. 4 and 5 are diagrammatic sectional views taken on the lines IV-IV and V-V of Fig. 3.

The nozzle as illustrated in Figs. 1 and 2 is provided with the usual circumferential blower passage 1 communicating with the vertical passages 2 in the upright conical members 3. This arrangement of blower passages is old in the art, and no novelty is claimed therefor. Any other type of blower arrangement might be used without affecting my invention in any way, such invention relating to the shape of the exhaust passage for the steam.

The lower interior portion of the nozzle marked 4 and lying below the line 5 (Fig. 2) is sli htly tapered as is common in nozzles, while the portion 6 lying above the line 5 is straight. Projecting inwardly from the surface 6 constituting the periphery of the upper portion of the passage, are the four lugs 7777, such lugs being preferably all the same in shape and size. The lower sides of these lugs are formed by inclined planes 8 and 9 (Fig. 2) so that the lugs are in vertical cross section substantially triangular. The converging. surfaces 8 and 9 meet on the line 10 which constitutes what may be termed the peak of the lug. This line 10 is inclined upwardly, as clearly indicated in Fig. 2. In the construction as I have used it the dimensions A, B, C, D, and E are as follows:

A6 inches B-l inch C- a inch D.1% inches E2 inches.

The results as hereinafter set forth were secured with a nozzle of the proportions aboveindicated, and these proportions are the best of which I am aware at the present time. It will be understood, however, that I do not regard my invention as limited to the foregoing proportions. It will also be understood that I do not regard my invention as limited to the number of lugs as shown, nor to the precise arrangement and shape shown, although this is the preferred arrangement, and the best one of which I have knowledge.

It will be seen that aside from the use of the lugs 7 the nozzle as above illustrated and described is the same throughout as the ordinary type of circular nozzle as almost universally used. The intended function of the lugs 7, and the one which I have found them to accomplish, is the breaking up or deforming of the body of steam as it issues from the nozzles, to a slight extent, but without reducing its velocity. This breaking up of the body of steam serves to secure a better entrainment of the gases in the smokebox, and when the mixture of steam and gases of combustion emerges from the stack they much more completely fill the stack than is the case where a round or circular nozzle of the old type is employed.

The general arrangement of the parts and the cross sectional form of the body of steam and gas are illustrated in Figs. 3, 4, and 5, wherein F indicates the nozzle, G indicates the petticoat pipe, and H the stack. At a point just above the nozzle the cross sectional area of the body of steam is as indicated in Fig. 5, such cross sectional area being somewhat similar to that of a Maltese cross. The lugs 7 cause the depressions 11, so that the central portion 12 is somewhat condensed. The entraining area of the body of steam is thus materially increased,

since the line 13 constituting the periphery of thebody of steam in the cross section is considerably greater than the circumference of the body of steam where a round nozzle is used. The openings or recesses 11 are relatively larger than might be expected passing body of steam. As a result of this arrangement a much better entrainment'of the gases of combustion is secured without an appreciable decrease in velocity, so that a much greater quantity of gas is pulled from the smoke box in a unit of time than is the case where a round nozzle is employed. The lugs are separated by relatively Wide v spaces sothat the lateral currents produced thereby in the stream of fluid issuing from the nozzle do not materially interfere with each other. closely adjacent, the surface of the stream is unduly agitated and broken up, thus increasing the resistance to the forward movement of the stream, reducing its velocity and producing increasedback pressure in the engine cylinders.

I have also found that the deformation of the body of steam by the lugs secures another important result tending to improve the draft. This result is the causing of the body of steam to spread out and completely fill the stack before its issuance therefrom, as indicated diagrammatically in Fig. 4. In other words, between the points 5-5 and 44 the steam spreads out and fills the stack more completely than is the case where an ordinary round nozzle is employed. \Vith the ordinary round nozzle I have found that there is always one portion of the stack which is not filled by the body of steam and in which there is practically no upward pressure, the point not filled ordinarily being the rear portion of the stack. I have found by means of gages placed at the top of the stack that the point of maximum pressure due to the upward velocity of the steam is at the center 14 of the stack,

and that such pressure gradually decreases as the edge of the stack is approached. With my improved nozzle I have found that the pressure is not only higher at the central portion 14 than is the case with a round nozzle of corresponding area and working under the same conditions, but also that- 'higher pressure is maintained throughout Otherwise, and with the lugs the cross sectional area of the stack, the upward pressure as indicated by gages being greater throughout the entire cross sectional area of the stack where my nozzle is employed, than is the case where a round nozzle is employed. lVith a greater upward velocity through the stack, the inference would be that a greater draft is produced in the smoke box, and this I have found to be the case, as a result of a large number of tests with both types of nozzles.

In comparing the results secured by my nozzle with the ordinary round nozzle I have employed a round nozzle of precisely the construction shown in Figs. 1 and 2, but with the exception that the lugs 7 are omitted and the diameter A reduced by a quar-' ter of an inch, so that the diameter of such round nozzle was 6% inches instead 6% inches, the cross sectional area of the outlets of the two nozzles thus being made substantially identical. With my nozzle I found as a result of repeated tests that the boiler limit upon a certain locomotive was increased 27 per cent. over the best performance attainable with the circular nozzle as above described. At equal evaporations I found the back pressure with my nozzle to be 11 per cent. less than with the said circular nozzle, and the ratio of the draft as indicated by manometers connected to the smoke box in the ratio of 16 to 9 in favor of the nozzle with the projections as indicated in Figs. 1 and 2 as opposed to the round nozzle having equal area, but without the lugs. The foregoing is a fair statement of the relative performance of the two nozzles under similar conditions, .upon a number of tests. It will be noted that the horizontal obstructing area of the lugs 7 is relatively slight as compared with the cross sectional area of the exhaust passage, the combined horizontal area of the lugs being 2% square inches as compared with a fraction over 83 square inches in cross sectional area of the nozzle. The utility of the lugs is not limited to use with a nozzle of exactly circular cross section, and it will be understood that the term circular is used in its generic sense to cover a deformed circular shape as well as a true or exact circular shape.' I have found that thenozz'le may be cheaply constructed, as it can be cast in the form illustrated, and used with practically no machine work, it not being necessary to bore out the interior where a smooth casting is secured.

What I claim is:

' 1. In combination, a locomotive exhaust pipe, a nozzle therefor having its passage communicating therewith and substantially circular in cross section at its outlet with a plurality of lugs projecting from the" periphery of the passage toward the center in the stream of fluid issuing from the nozzle do not materially interfere with each other.

2. In combination, a locomotive exhaust pipe, a nozzle therefor having its passage communicating therewith and substantially circular in cross section at its outlet, with a plurality of lugs projecting from the periphery of the passage toward the center thereof and spaced apart distances such that the lateral currents produced by such lugs in the stream of fluid issuing from the nozzle do not materially interfere with each other, the spacing of the said lugs around the periphery being substantially uniform.

3. In combination, a locomotive exhaust pipe, a nozzle therefor having its passage communicating therewith and substantially circular in cross section at its outlet with a plurality of lugs projecting from the periphery of the passage toward the center thereof and spaced apart distances such that the lateral currents produced by such lugs in the stream. of fluid issuing from the nozzle do not materially interfere with each other, the combined obstructing area of the lugs in a horizontal plane being less than ten per cent. of the cross sectional area of the passage.

In testimony whereof I have hereunto signed my name in the presence of the two subscribed witnesses. I

FRANK A. GOODFELLOW. lVitnesses:

J. T. HANLQN, S. E. GEARHABT.

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