US2090469A - Automatic continuous blow-down - Google Patents

Description

g- 1937. R. w. CHORLEY ET AL AUTOMATIC CONTINUOUS BLOW-DOWN Original Fi-led March 22, 1934 2 Sheets-Sheet l Aug. 17, 1937. R. w. CHORLEY ET AL 6 AUTOMATIC CONTINUOUS BLOW-DOWN Original Filed March 22, 1934 2 Sheets-Sheet 2 Patented Aug. 17 1937 "UNITED [STATES AUTOMATIC CONTINUOUS BLOW-DOWN Raymond W. Chorley, Indianapolis, Ind., and Thomas W. Demarest, Chicago, 111., assignors to National Aluminate Corporation, Chicago, 111., a corporation of Delaware Application March 22, 1934, Serial No. 716,840 Renewed January 12, 1937 3 Claims.

This invention relates to automatic blowdown devices for boilers, and more particularly to continuous automatic blowdown devices for permanent installation in connection with railway locomotives and wherein the blowdown operation is preferably automatically controlled by the withdrawal of steam from the boiler during the normal operation of the locomotive.

In the operation of steam boilers a considerable concentration of soluble salts as well as other foreign matter or sediment accumulates in the water and may become very detrimental to the efiicient operation of the boiler. In practice it is desirable to maintain the concentration below a predetermined amount, in order to prevent foaming, priming and other detrimental effects of a high concentration. This may.be accomplished by blowing down, either intermittently or continuously, in order to prevent an undue accumul-ation.

It is an object of the present invention to provide an automatic blowdown device for installation in connection with a steam boiler and which will be efiective to continuously reduce the concentration therein as long as steam is being withdrawn from the boiler for use in a suitable steam-operated device, or in fact for any purpose.

The present invention provides an automatic blowdown device in which any steam pressure above a predetermined low may be used to overcome a boiler pressure and cause a continuous blowdown as long as the said steam pressure is maintained above the predetermined low.

A particular object of the invention is to provide an automatic continuous blowdown device in which a variable steam pressure, preferably in the steam chest of a locomotive, may be employed to overcome comparatively high steam pressure in the boiler and cause a continuous blowdown to take place as long as the variable is maintained. I

A further object is to provide an efiicient type of automatic valvefor use in a blowdown system in which the valve may be opened against high steam pressure by the use of comparatively low steam pressure and in which the valve will automatically close with a predetermined reduction of the low pressure.

- The invention also contemplates an automatic blowdown device for use with locomotives in which the blowdown is automatically accomplished by opening the throttle in the normal act of starting the engine and stopped by closing the throttle.

A still further object is the provision of an automatic continuous blowdown, which may be entirely automatic in operation, of few parts easy to install, and not likely to get out of order.

Further objects will be apparent from the specification and appended claims.

In the drawings:

Figure 1 is a diagrammatic side elevation of a locomotive partially broken away and illustrates one embodiment of the invention associated therewith.

Fig. 2 is a plan view partially in section of the valves of the blowdown device and illustrates a method of connection to provide a boiler outlet through the automatic valve.

Fig. 3 is a vertical section through the automatic blowdown valve taken on a line corresponding substantially to line 3-3 of Fig. 2.

Fig. 4 is a side elevation of the valve seat bushmg.

Fig. 5 is a side elevation of the end of the drain pipe.

Fig. 6 is an end elevation of the drain pipe end shown in Fig. 5.

Referring to the drawings in detail, the embodiment illustrated comprises a locomotive having the usual boiler I and a steam chest 2 to which steam may "be admitted by operation of the usual throttle valve 2 for controlling the engine.

A manually operated angle valve 3 is connected to the boiler in a manner to provide a blow-oil outlet therefrom, and a perforated nipple 4, or other suitable means, may be connected to the outlet within the boiler for the purpose of preventing scale from entering in and clogging the blow-off conduits. The outlet end of the valve 3 is provided with a plug 5 threaded therein and having a restricted orifice 6 to limit the flow from the boiler, irrespective of the size of the opening through the valve 3.

Experience has shown that different boilers, or the same boilers under different conditions, require different rates of blowdown, which may be governed by varying the size of the orifice 6. The plug 5 is, therefore, made easily removable, whereby the size of the orifice may be varied or a new plug inserted. The orifice governs the rate of blowdown and may be positioned at any point in the blowdown conduit although it is preferably placed between the boiler and a blowdown valve which will be described later.

The manual valve 3 is connected to an automatic valve 1 by means of a pipe nipple 8, and

the valve 1 is provided with a steam conduit 9 connected therewith and with the steam chest 2 or other suitable steam source of the locomotive,

whereby steam may be admitted to one side of the automatic valve. The valve 1 is also provided with a discharge conduit llLjwhich is a continuation of the blowdown conduit from the boiler. The steam conduit 9 is preferably connected to, or adjacent, the steam chest, although it may be connected to any suitable point in the steam line from the throttle valve to the engine cylinders, whereby the blowdown is controlled by operation of the throttle.

The automatic valve 1 (Fig. 3) comprises a body portion into which the conduits 8, 9, and Ill are threaded, and is provided with a vertical longitudinal passage therethrough with which these conduits communicate and into which is threaded a valve seat bushing i2. The ends of the valve passage are closed by suitable plugs l3.

The valve bushing i2 is provided with a central passage I4 and radial openings l5 communicating with a lateral groove l5 around the bushing. This groove l5 may be either in the bushing or in the casing or both, and communicates with the discharge pipe l0 as shown. A slot IS in the end of the valve bushing permits the use of a suitable tool whereby the bushing may be threaded into the valve casing. After the bushing is completely threaded in position, the lower threaded end is preferably swaged slightly at IT to retain it snugly in place and to prevent leakage. The automatic valve 1 is preferably mounted in a vertical position and adjacent the manual-valve 3 as shown.

The upper end of the bushing I2 is provided with a valve seat i8, on which is supported a suitable ball check valve IS. The valve may be horizontally positioned in which case the ball 40houslng may be inclined in a manner to cause the ball to seat by gravity. When the manually controlled valve 3 is open, the ball valve |9 will be snugly maintained against its seat by steam pressure from the boiler. The valve seat H! for 45 the ball I9 is preferably conical and so shaped that the ball, which is comparatively large relative to the opening, seats adjacent the periphery of the opening, therefore providing a comparatively small efiective pressure area on the ball,

tending to maintain the valve closed.

The lower end of the vertical passage through the automatic valve casing provides a cylinder 20 in which is mounted a piston 2|, on the upper side of which is a conical valve portion 22 arranged 56 to seat snugly in a valve seat 23 formed on the lower end of the bushing |2 when the piston is moved upwardly by steam pressure applied in the cylinder 20. The piston 2| is provided with an upwardly extending portion 24, and, when the piston is operated by steam pressure in the cylinder 20 to close the conical valve at the lower end of the bushing, the portion 24.will engage the ball valve l9 and raise it from the seat 18, thereby allowing the passage of water and sediment from the boiler to the discharge pipe l0.

Boilers of the type herein described are normally operated at a high pressure, and the pressure in the steam chest is variable and at times may be relatively low, and, in order that such variable or comparatively low steam pressure ad 'tted to the valve cylinder 20 may overcome a 2%atively high pressure from the boiler on the all or check valve I9, the piston 2| is made sufliciently large to provide an effective pressure- !6 area ratio between the piston 2| and the ball valve l9 whereby relatively low pressure in the cylinder 20 will overcome the high pressure against th ball valve and the valve will be opened an maintained in open position as long as the throttle remains open and a pressure above a predetermined limit is maintained. A continous blowdown discharge will, therefore, take place through the discharge pipe II) when the throttle is open and will stop when the throttle is closed.

The boiler outlet manual valve 3 and the automatic valve 1, may be located as shown in the drawings, although other locations are suitable and they may be located in the cab if desired.

The discharge pipe l0 communicates with a centrifugal separator 26 by which the steam is separated from the water and sediment. This separator is of the usual centrifugal type commonly used for such purposes and, when the device is used on a locomotive, is preferably elevated as shown in Fig. 1 in order that the steam released from the upper side thereof in the usual manner may be discharged over the top of the cab. The water outlet of the separator comprises a downwardly extending pipe 21 which is arranged to discharge adjacent the road bed.

A drain pipe 28 is connected to the discharge pipe l0 and extends downwardly and into the ash pit 29. The end of the drain pipe in the ash pit is provided with a cap 30 having a very small drain hole 3| therethrough. The size of this drain hole is only sufiicient to allow the water to drain from the various conduits when the device is not in operation. The drain pipe is particularly useful for preventing the water from freezing in the pipes.

In the normal condition of the device, the man ual valve 3 is completely open, and, when the engine is not in operation, the pressure from the boiler maintains the ball valve l9 closed. How-' ever, as soon as the throttle is opened and steam is admitted to the steam chest 2 and through the pipe 9 into the cylinder 20, the piston valve 2| will be raised, thereby opening the ball valve I9 and allowing the high pressure blowdown discharge through the pipe i0. Simultaneously with the opening of the ball valve IS, the passage through the valve bushing I2 is completely closed by the piston valve 2|. The ball valve l9 on the high pressure side is, of course, self-closing as soon as the throttle is closed and the pressure on the piston 2| is relieved. The automatic valve 1 is normally installed in a vertical position as shown and the ball valve l9 tends to seat by gravity.

Modifications may be made without departing from the spirit of the invention, and it is, therefore, desired that the invention may be limited only by the prior art and the scope of the appended claims.

Having thus described this invention, what is claimed and desired to be secured by Letters Patent is: i

1. An automatic \blowdown valve, comprising a casing having a vertical opening therein and a blowdown inlet and a steam inlet communicating with the upper and lower ends of said opening, respectively, and a blowdown outlet communicating intermediate said inlets, a valve bushing secured in said opening intermediate said inlets and having a vertical restricted passage therethroughand a lateral passage communicating with said outlet, a valve seat at each end of said restricted passage, a ball cooperating with the upper valve seat to normally close said restricted having a. portion extending into said restricted portion adjacent said first valve, said piston beingpassage, a normally open piston valve for cooperation with the lower valve seat and having a portion extending into said restricted portion adjacent said ball, said piston being operable to simultaneously raise said ball and close said piston valve by steam pressure.

2. An automatic blowdown valve, comprising a casing having a vertical opening therein and a blowdown inlet and a steam inletcommunicating with the upper and lower ends of said opening, respectively, and a blowdown outlet commu'nicating intermediate said inlets, a valve bushing secured in said opening intermediate said inlets and having a vertical restricted passage therethrough and a lateral passage communicating with said outlet, a valve seat at each end of said restricted passage, a valve cooperating with the upper valve seat to normally close said ree vstricted passage, a normally open piston valve for cooperation with the lower valve seat, and

operable to simultaneously raise said first valve and close said piston valve by steam pressure.

3. A blowdown valve comprising a casing having a passage therethrough, threaded plugs closing each end of said passage, a pressure inlet 7 communicating with each end of said passage, a bushing in said passage between said inlets and having a restricted passage therethrough, a valve seat at each end of the restricted passage, a valve cooperating with each valve seat and arranged to close the adjacent end of said restricted passage by pressure from its respective inlet, means causing one valve to open when the other is closed, and an outlet communicating with said restricted passage between said valves.

RAYMOND w. CHORLEY; THOMAS w, DEMAREST.

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