US1774518A - Locomotive stoker - Google Patents

Description

Sept 9 E930.

' Filed Dec. 12, 1925 N. LOWER LOCOMOTIVE STOKER LWQ M 3 Sheets-Sheet l 25/ :ETJQTJET".

20 '2 [MIX/Z222 [ml/er Sept.2,1930. N. M. LOWER 1,774,513

LdcoMoTIvE STOKER Filed Dec. 12, .1925

3 Sheets Sheet 2 Sept. 2, 1930.

Filed D90. 12, 1925 N. M. LOWER 74,518

LOCOMOTIVE STOKER 3 Sheets-Sheet 3 Pm/zemr being open for the relatively free escape of steam on the exhaust side of the piston 1s ob-' Patented Sept. 2, 1930 UNITED STATES PATENT -OFFICE NATHAN M. LOWER, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO THE STANDARD STOKER COMPANY INC., 0]? NEW YORK, N. Y., A, COR- PORATION OF DELAWARE LOGOMOTIVE STOKER Application filed December 12, 1925. Serial No. 75,029.

. 5 ation, and to recover a portion of the energy in the exhaust steam.

Stoking mechanisms for locomotives usually include means for transferring the coal from the tender to the locomotive, reducing the lumps to suitable size, and elevating the coal to a suitable point, or points, for distribution, which may be either within' or without the fire box.

The power necessary to drive the conveying mechanism under normal conditions is insufficient to continue the operation of the stoker when large or tough lumps of coal are to be crushed. If the power necessary to crush the lumps is provided by increasing the pressure behind the piston, there .will be considerable excess force remaining in the piston when the lump has yielded, and, hence, there will be a tendency for the piston to move too rapidly for safety of the mechanism. This 25 is especially true in the case of engines where.

the power is transmitted without the intermediary of a crank shaft and the load is applied through overrunning clutch mechamsm.

According to the present invention, in its preferred form, the inlet steam port is open during practically the entire stroke of the piston and the steam supply line is open sufiicientlv to provide pressure for all ordinary emergencies, and the exhaust, instead of structed or throttled to create more or less back pressure on the exhaust side of the piston and, thus, to a greater or less extent,.reduce the effective pressure on the piston.

With this arrangement the speed of the engine under normal load is automatically controlled by the speed with which the ex- .50 creases the power to take care of extra loads.

haust can escape. Hence, byregulating the throttling of the exhaust, the normal speed For example, when a large or tough lump is to be crushed the extra load will check the piston and simultaneously the pressure will u1ld up on the inlet side of the piston and Will leak away on the exhaust side, thus rapidly increasing the effective pressure on the piston until it is sufficient to overcome the resistance. Upon release from the extraordinary loadthe increased effective pressure on the piston will accelerate its speed and this, in turn, will quickly build up the back pressure on the exhaust side. The latter eflect is especially true when the throttling is such as to maintain at all times a certain minimum'back pressure.

Maintaining certain minimum back pressure is of advantage when the exhaust steam is used to heat the feed water for the boiler. For, by making the minimum equal to, or above, that created by passing the exhaust into the feed water heater, the operation of the stoker is rendered substantially uniform whether the heater is in operation or not.

In the drawings Fig. 1 is a rear elevation of a locomotive equipped with a stoker organized according to the preferred form of the invention, parts being broken away; 1 F Fig. 2 is a side elevation of a fragment of ig. 3 is a longitudinal section through the preferred form of engine with a longitudinal section through the back pressure valve in the exhaust line and a diagrammatic representation of a pre-heating system for the feed water;

indicates a locomotive cab having a deck 11,

and 12 is the back head of the locomotive equipped with the ordinary firing door 13.

The stoker includes a transfer conveyor having a trough 14 and transfer screw 15 and two elevators having casings 16 and 17 in which are mounted elevating screws 18 and 19. r

The three screws are driven by a single reciprocating rack 20 which has teeth meshing with gears 21, 22 and 23, associated with the screws and driving them through over-running clutches 24, 25 and 26, substantially as described and illustrated in the co-pending application of Nathan M. Lower, Serial Number 86,843, filed February 8, 1926, and Patents No. 1,303,333 of December 28, 1920, and No. 1,371,252 of March 15, 1921.

The rack is preferably driven by a steam engine 27 (Fig. 1) of the IVestinghouse type improved as disclosed, and claimed in the co-pending application of Messrs. Chalker and Turner, Serial Number 71,510, filed November 27, 1925, but neither the particular engine shown nor this type is essential.

Referring to the sectional view shown in Fig. 3, the engine includes a cylinder 28 equipped with a piston 29 and having steam passages 30 and 31 communicating with the cylinder on opposite sides of the piston, and supply and exhaust passages 32 and 33 alternately put in communication with the steam passages 30 and 31 by a distributing valve D, the position of which is controlled by a control valve C, and this latter is shifted by a valve stem 34 in cooperation with a plate 35 carried by the piston 29.

The detailed construction of the engine is fully set forth in the application above referred to and, for brevity, is omitted here. It will be sufiicient to say that the distributing valve D remains in position to admit steam behind the piston and allow the escape of the exhaust steam in front of the piston during practically the entire stroke.

Steam is supplied to the engine through a supply line 36 connected with the passage 32 and exhausted through an exhaust line 37 connected with the passage 33. The supply line is opened and closed by a valve 38 and the exhaust is throttled by a valve which is preferably located beneath the deck and equipped with an extension stem 39 presenting a handle 40 above the deck and readily accessible to the fireman.

According to the present invention the steam supply line 36 will be opened to supply steam to the engine sufiicient to keep it in operation during ordinary emergencies as well as under the load of transferring coal, and the exhaust line is throttled to maintain more or less back pressure on the piston.

With two hundred (200) pounds of steam the engine shown will operate through about 150 cycles per minute with the normal load on the transfer and elevating screws. Usually a much smaller number of cycles will supply ample coal to keep up the necessary evaporation for the work of the locomotive. By throttling the exhaust, the back pressure can be made to reduce the effective pressure and thus control the speed of the piston and make the number of cycles justwhat may be required under any particular circumstances.

When any unusual load is thrown on the motor such as the crushing of a large or tough lump of coal, the piston will be checked, the exhaust steam will leak away rapidly and the pressure will build up rapidly on the inlet side. The result is a very qick rise in effective pressure to overcome the resistance of the lump. If the lump yields suddenly the piston will speed up, but the back pressure will increase at a corresponding speed and soon reduce the piston to its normal rate of movement.

It is not necessary to use a valve that will maintain a certain minimum back pressure in the exhaust line, but there is an advantage in so doing because it will prevent a green or careless fireman from starting his stoker under conditions that would permit dangerous speed of the piston. Such a valve also has particular advantages when the exhaust steam from the stoker engine is to be used for preheating feed Water, as hereinafter explained.

The crusher may be of any type desired, but preferably the type shown in the patent to Lower, No. 1,404,985, January 31, 1922, is mounted adjacent to the transfer screw as indicated as 40 in Fig. 1.

Almost all locomotives as at present con structed are equipped with one or more steam operated accessory motors for operat ing the air pump, the electric light generator, the stoker, etc. In order to conserve the heat that would otherwise be lost in the exhaust of these accessory motors suitable means are provided for utilizing the heat in the exhaust for assisting in preheating the water for the locomotive boiler. As shown in Fig. 3, the exhaust from the stoker motor is employed to assist in preheating the Water supplied to the boiler.

As is usual in such constructions, a portion of the exhaust from the locomotive engine is employed to heat the water in the preheating tank 78. This exhaust is led from the main exhaust passages 99 through the branch exhaust passage formed by the pipes 100, 101, and 102 into the preheating tank 78. A check valve 103 in the passage prevents surging of the pressure back and forth through said passage. In other words, this check valve prevents the pressure in the tank from forcing steam or water back alon the passage 100. WVater enters the tan 78 through the pipe 83 and is pumped into the locomotive boiler from said tank through the pipe 84 in the usual manner.

he exhaust from the stroke motor 27 is led through the exhaust pipes 79, 81, into the pipe 102. and thence into the heater 78.

The back pressure at the exhaust nozzle 104 will vary considerably due to the different operating conditions of the engine. In order, therefore, that this back pressure shall not affect the operation of the stoker engine a 78 through the pipe 81 and connecting pipe 102, as shown diagramatically in Fig. 3 and more in detail in Fig. 5. 1

The valve 80 comprises a valve'hou sing divided by the partition 86 into two chambers 87 and 88 which are in communication with the pipes 79 and 81, respectively. A sleeve 89 provided with apertures 91 in its wall opening into the chamber 88 is secured in the partition 86 with its lower end opening into the chamber 87. A plunger 92 is slidably mounted in the sleeve and is held in position between the springs 93 and 94. The tension of the spring 94: is adjusted. by means of the stud 95 threaded in the nut 96 and engaging the lower end of the spring 9 1.. The tension of the spring 93-is adjusted by means of the plug 97 threaded in the upper end of the valve housing- The plug 97 may be operated by means of a handle 98 which may extend within convenient reach of the operator.

N hen the plunger 92 is forced upward by the pressure of the exhaust in the pipe 79, the ports 91 are uncovered to permit the exhaust to enter the water in the tank 78 for heating the same. The tension of the springs 93 and 94; is so adjusted that the ports 91 will not be uncovered until the pressure on the plunger 92 reaches a predetermined amount. By adjusting the springs so that the ports 91 will not be opened until the pressure on the plunger 92 is substantially that of the maximum back pressure developed, the ressure in the pipe 4 stant, whereby the speed of the stolrer motor 3 1 will remain substantially uniform.

Suitable means are provided for relieving the back pressure when the same rises above a predetermined amount in the pipe 101. As shown diagrammatically in Fig. 3 and more in detail in Fig. 5, a by-pass around the valve 103 is provided for this purpose. The bypass, as illustrated, comprise a pipe 105 which connects the pipe 101 with the exhaust passage 99 and is provided with a pressure relief valve 106. The .valve 106 may be a relief pressure valve similar tothe valve 80 or it may beof any other approved type.

When the pressure within the pipe 101 rises above a predetermined amount preferably somewhat below that at which the valve 80 in the pipe 79 is set, the valve 106 will open and relieve the pressure. By this arrangement pressure in the. pipe 81 will not interfere with the exhaust from the stoker past the valve 80, and consequentl the operation of the stoker will remain fair y constant.

In Fig. d is shown diagrammatically a 9 will be maintained fairly conmodified form of construction in which the exhaust from all the accessory motors is employed for assisting in heating the water supplied to the boiler of the locomotive, the construction otherwise being similar to the construction shown in detailin Fig.5. In this construction the heater 107 may be of any approved construction. The water enters the heater at 108 and passes from the heater through the pipe 109 into the boiler. A portion of the exhaust from the locomotive engine is, also employed to heat the water in the heater tank. As shown, steam from the exhaust passages 99 is led through pipesi110 and 111 into the heater107. The pipe 111 is provided with a check valve 112 which in construction and function is similar to the valve 103 in Fig. 3. The exhaust from the stoker motor 11% is led to the heater 107 through the pipe 115 which is connected to the pi e 111. The pipe 115 is provided with a chec valve 116 which is preferably of the same construction as the valve 80 shown in Fig. 3 and Fig. 5. The exhaust from the remaining motors, as the electric light generator, turbine motor 117 and the air pump motor 118 is conducted into the pipe 111 as by being connected to the pipe 115. A bypass 119 between the pipe 111 and the exhaust passage 99 is provided with a pressure relief valve similar to the valve 80 whereby when the pressure in the pipe 111 exceeds a predetermined amount the valve will automatically open and relieve the pressure.

' T claim as my invention: I

1. In a locomotive stoker, the combination of fuel conveying mechanism and a steam engine driving such mechanism, including a cylinder, a piston reciprocating therein, steam passages communicating with the cylinder to admit and exhaust steam, a distributing valve controlling said passages, means for actuating the distributing valve and holding the admission passage open during substantially the entire stroke of the piston and an automatically operated valve for controlling the escape of the exhaust steam.

2. In a locomotive stoker, the combination of fuel conveying mechanism and a steam engine driving such mechanism, including a cylinder, a piston reciprocating therein, steam passages communicating with the cylinder to admit and exhaust steam, a distributing valve controlling said passages,'means for actuating the distributing valve and holding the admission passage open during substantially the entire stroke of the piston and a pressure sensative valve for controlling the escape of exhaust steam.

3. In a locomotive stoker, the combination of fuel conveying mechanism, a steam engine including a cylinder, a piston reciprocating therein, steam passages communicating with the cylinder to admit and exhaust steam,

transmission mechanism connecting the piston and the fuel conveying mechanism including overrunning clutch mechanism, a valve mechanism for controlling the steam passages and permitting the admission passage to remain open during practically the entire stroke of the piston, and a manually operated valve for throttling the escape of exhaust steam.

4. In a stoker, the combination of fuel conveying mechanism, an engine for driving said mechanism, including a cylinder, a piston reciprocating in the cylinder, steam passages communicating with the cylinder to admit and exhaust steam, valve mechanism controlling said passages and operating to admit steam during substantially the entire stroke of the piston, a valve controlling the supply of steam, and an adjustable valve for throttling the escape of exhaust steam.

5. In a device of the class described, the combination of a locomotive, fuel conveying mechanism, a steam engine for driving said mechanism located below the deck of the locomotive,asteamsupplylineconnectingsaid steam engine With the boiler of the locomotive, a valve controlling the steam line, a manually operated valve for throttling the exhaust of the steam engine, and means accessible above the deck of the locomotive for operating the last mentioned valve.

6. In combination, a locomotive, a stoker, a motor therefor, a pre-heater water tank, a

conduit for conducting a portion of the locomotive exhaust into said tank for heating the same, a check valve in said conduit, a bypass around said check valve, a conduit for conducting the exhaust from said motor into said tank to heat the water therein, a pressure valve in said last named conduit, and a pressure relief valve in said by-pass.

7 In a locomotive stoker, the combination of fuel conveying mechanism and a steam engine driving such mechanism, including an overrunning clutch between said mechanisms, a cylinder, a piston reciprocating therein, steam passages communicating with the cylinder to admit and exhaust steam, a distributing valve controlling said passages, means for actuating the distributing valve and holding the admission passage open during substantially the entire stroke of the piston, a preheating water tank, a conduit for conducting the exhaust from the engine to the Water tank and a pressure sensitive valve in said conduit anterior of said tank for controlling the escape of exhaust steam.

8. In a locomotive stoker, the combination of fuel conveying mechanism and a steam engine driving such mechanism, including an overrunning clutch between said mechanisms, a cylinder, a piston reciprocating therein, steam passages communicating With the cylindex to admit and exhaust steam, a distributing valve controlling said passages, means for actuating the distributing valve and hold-- magma ing the admission passage open during substantially the entire stroke of the piston, a preheating Water tank, a conduit for conducting the exhaust from said engine to said tank and a back pressure valve in said conduit anterior of said tank for controlling the passage of exhaust steam.

9. In a locomotive stoker, the combination of fuel conveying mechanism, a reciprocating engine, means for connecting said engine to said mechanism whereby more power is normally required to operate the piston of said engine in one direction than in the other, and a pressure operated valve in the exhaust of said engine for preventing the pressure in said exhaust anterior of said valve from falling below a predetermined minimum during the normal operation of the engine.

In testimony whereof I aifix my signature.

NATHAN M. LOWER.

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