US2267941A - Means to prevent flooding of feedwater heaters - Google Patents

Description

Dc. 30,1941. c. J. MILLER 2,267,941

MEANS TO PREVENT FLQODING OF FEED-WATER HEATERS Filed April 30, 1958 INVENTOR w. M m /n A m C Patented Dec. 30, 1941 MEANS TO PREVENT FLOODING OF FEED- WATER HEATERS Charles J. Miller, Valley Cottage, N. Y., assignor to The Superheater Company, New York, N. Y.

Application April 30, 1938, Serial No. 205,197

Claims.

This invention relates to improvements in feed water heating systems for locomotives and particularly to means for preventing flooding of a closed type feed water heater by water flowing back from the water tank on the locomotive tender through a conduit provided for discharging heating steam condensate from the heater into the tank.

Many locomotives are provided with feed water heaters of the closed type which comprise one or more coils through which the feed Water is circulated to be heated by exhaust steam from the locomotive engines when the engine is operating or by steam from some other source when the locomotive engines are not operating. Part or all of the steam admitted to the heater casing is condensed and a conduit is connected between the steam space of the heater and the locomotive water tank so as to reclaim the water and the heat therein by discharging the condensate into the water tank. It has been observed that when the water tankon the tender is full or nearly full and the locomotive is traveling down-grade with the engine drifting, there is danger that water from the tank may flow back through the condensate conduit into the steam space of the heater and thence into the engines. This is due to the fact that when the locomotive is on a down-grade and the water tank is nearly full the water level is at a higher elevation than the connection of the steam pipes to the heater which is located at the front of the locomotive, and the longer the locomotive or the steeper the grade, the greater is the difference in elevation.

It is an object of the present invention to obviate the above mentioned disadvantage by providing valve means associated with the feed water heating system so arranged that the condensate conduit from the heater to the water tank is closed ofi when the engines are out of operation and any condensate is discharged to some other point.

The invention will be best understood upon consideration of the following detailed description of an illustrative embodiment thereof when read in conjunction with the accompanying drawing, in which:

Fig. 1 is a diagrammatic elevational view of a locomotive provided witha feed water heating system embodying the present invention, parts being shown in section to illustrate details of construction; and

Fig. 2 is a sectional view of a modified form of the valve means illustrated in Fig. 1.-

In the drawing, the numeral l0 designates a feed water heater of the closed type mounted in the smoke box at the front of the locomotive forwardly of and adjacent to the smoke stack. Feed water is withdrawn from the tank on the locomotive tender by the boiler feed pump (not shown) and forced through a pipe ll connected to one or more coils l2 to be heated by exhaust steam supplied to the interior of the heater casing through a conduit l3 connected to the exhaust of the locomotive engine, the feed water being discharged into the locomotive boiler through pipe I la. When the engines are not in operation and water is being pumped into the boiler, steam is supplied to the heater through a pipe I4, this steam being either live steam from the boiler or exhaust steam from some continuously operating auxiliary on the locomotive, such as a stoked engine. Many heaters of this type are provided with a bafiie l5 extending inwardly from the inner wall of the heater casing at a point below the steam connections and thence upwardly to a point above these connections. Water condensed from the steam supplied to the heater is discharged into the Water tank H on the locomotive tender through a conduit designated Ilia, lfib, I60.

Although the baffle [5 has the effect of raising the point at which the exhaust steam connection I3 is made to the heater casing, there is danger that when the water tank on the tender is full and the engine drifting down-grade, the water level may be at a higher elevation than the top edge of the bafile I5, with the result that Water which flows back through the conduit I611, 16b, 16c, into the heater casing would flow over the top of the baffle l5 and pass through the conduit 13 into the locomotive engine. In one form of the invention it is contemplated to prevent water flowing back into the heater casing by providing a check valve Win the condensate conduit so arranged as to permit condensate to pass to the water tank but preventing a reverse flow. In addition a valve-controlled drain pipe 20 is provided for discharging condensate from the heater casing to some point other than the water tank when the engines are not operating.' As shown in Fig. *1, a valve casing 21 is interposed between the sections Ito and 16b of the condensate conduit. the flow between these two sections being through the chamber 22 in the valve casing. Within the valve casing is a valve 23 secured to a piston 24 located in a cylinder 2-5 which is connected by a pipe '26 to the steam pipe 21 supply-ing live steam to the engine.

A spring 28 acting against the piston 24 urges the valve 23 towards its open position.

When the locomotive engines are in operation, the steam pressure is communicated through pipe 26 to the cylinder and acts on the piston 24 to close the valve 23 so that communication between the chamber 22 and drainpipe 20 is cut off. The pressure of exhaust steam supplied to the interior of the heater casing through the conduit I3 is suificient to expel any condensate through the conduit Ilia, I61), I60, past the check valve I8 into the water tank l1. Whenever the locomotive engine is out 01f, piston 24 is relieved of steam pressure and spring 28 acts to open the valve 23 so that condensate may be drained from the heater through conduit section Ilia, chamber 22, past the opened valve 23 to the drain pipe 20. If at such times the locomotive is traveling downgrade and the water tank on the tenderis full, the pressure of water in section I60 closes the check valve [8 so that water may not reach the interior of the heater and pass from the latter into the engine through the conduit l3.

The form of valve shown in Fig 2 includes an additional valve member 30 controlling flow from conduit section lBa through a chamber 3| to conduit section [6b. The positions of the valve members shown in Fig. 2 assume that the engine is not operating, with the result that valve member 23 is unseated by spring 28, permitting flow from condensate conduit section ISa through chamber 30 and out through the drain pipe 20. When the engines are operating, steam is admitted through pipe 26 to act on piston 24 to seat valve member 23 and unseat valve member 30. Consequently flow to the drain pipe 20 is closed off and condensate is discharged into the water tank through conduit sections I62) and I60. It is obvious that when this form of valve is employed a check valve such as l8 (Fig. 1) is not necessary.

It will be apparent from the above description that with either valve arrangement water cannot flow from the water tank in the tender back through the condensate conduit into the heater and thence to the engines when the latter are out of operation. Both arrangements also provide for discharging any water condensed from steam admitted to the heater while the engines are out of operation. The arrangements shown and described also allow, other conditions permitting, the heater to be located at a lower point in the smoke box than has heretofore been customary because it is no longer necessary to place the heater in as high a position as possible in order to prevent its being flooded. In addition, the bailie [5 may also be omitted except in cases where its employment is desired to prevent steam being blown directly against the water coils I2.

Although illustrative embodiments of the invention have been shown and described in detail herein, it is apparent that many changes and variations may be made without departing from the invention. Accordingly it is desired and intended to include all such changes and variations within the scope of the appended claims.

What I claim is:

1. In a locomotive feed water heating system having a feed water heater of the closed type, a feed water tank, means for circulating feed water through said heater from said tank, means for supplying exhaust steam to said heater from the locomotive engine, other means for supplying heating steam to said heater, and a conduit leading from said heater to said tank for discharging thereto water condensed from the heating steam; a valve controlling now through said conduit so arranged as to prevent water flowing from said tank through said conduit to the steam space of said heater; a drain pipe associated with said heater for discharging to a point other than said tank the water condensed from heating steam supplied by said other means when said engine is not functioning; a valve controlling said drain pipe; means responsive to the operation of said engine for closing said drain pipe valve when the engine is operating; and means for opening said drain pipe valve to prevent said condensate entering the locomotive engine by way of the connection supplying exhaust steam therefrom to said heater.

2. In a locomotive feed water heating system having a feed water heater of the closed type, a feed water tank, means for circulating feed water through said heater from said tank, means for supplying exhaust steam to said heater from the locomotive engine, other means for supplying heating steam to said heater, and a conduit leading from said heater to said tank for discharging thereto water condensed from the heating steam; a valve controlling flow through said conduit so arranged as to prevent water flowing from said tank through said conduit to the steam space of said heater; a drain pipe connected to said conduit at a point between said heater and valve for discharging Water condensed from heating steam supplied by said other means when said engine is not functioning; a valve controlling said drain pipe; means responsive to the operation of said engine for closing said drain pipe valve; and means for opening said drain pipe valve to discharge condensate from said heater through said drain pipe for preventing said condensate entering the locomotive engine by way of the connection to supply exhaust steam therefrom to said heater.

3. In a feed water heating system for a locomotive having a feed water heater of the closed type at or near its front end through which feed water is circulated from a tank on the tender to be heated by steam from the exhaust of the engines, and a conduit connected to said heater and tank for discharging condensate water from the heating steam into said tank, and wherein the heater is so located with respect to the water level in said tank that when the latter is substantially full and the locomotive is travelling down grade with the engines out of operation there is danger of water flowing back from said tank through said conduit into the steam space of said heater and thence into the locomotive engines; a valve controlling said conduit; means responsive .to the operation of the locomotive engines for opening said valve; and means operativeto close said valve when said engines are not functioning.

4. In a feed water heating system for a locomotive having a feed water heater of the closed type at or near its front end through which feed Water is circulated from a tank on the tender to be heated by steam from the exhaust of the engines, and a conduit connected to said heater and tank for discharging condensate water from the heating steam into said tank, and wherein the heater is so located with respect to the water level in said tank that when the latter is substantially full and the locomotive is travelling down grade with the engines out of operation there is danger of water flowing back from said tank through said conduit into the steam space of said heater and thence into the locomotive engines; a check valve in said conduit so arranged as to be closed by water flowing from said tank toward said heater and to be opened by condensate forced through said conduit toward said tank by the pressure of exhaust steam in said heater; other means for supplying steam to said heater, a drain associated with said heater for discharging condensate to a point other than said tank for discharging water condensed from heating steam supplied by said other means when said engine is not functioning; a valve controlling flow through said drain pipe; means responsive to the operation of the locomotive engines for closing said valve; and means acting to open said valve when the engine is not operating for preventing said condensate entering the locomotive engine by way of the connection for supplying exhaust steam therefrom to said heater.

5. In a locomotive feed water heating system having a feed water heater of the closed type, a feed water tank, means for circulating feed Water through said heater from said tank, means for supplying exhaust steam to said heater from the locomotive engine, other means for supplying heating steam to said heater, and a conduit leading from said heater to said tank for discharging thereto water condensed from the heating steam; a drain pipe associated with said heat er for discharging to a point other than said tank the water condensed from heating steam supplied by said other means when said engine is not functioning; a valve in said conduit arranged to prevent water flowing from said tank to said heater; a valve in said drain pipe arranged to permit condensate to be discharged from said heater through said drain pipe for preventing said condensate entering the locomotive engine by way of the connection supplying exhaust steam therefrom to said heater; and means responsive to the admission of steam to said engine for opening said first valve to permit condensate to flow through said conduit into said tank and for closing said second valve to prevent condensate being discharged through said drain pipe, and means for moving the said valves to the opposite position upon the exclusion of steam from said engine.

CHARLES J. MILLER.

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