US2437673A - Low-pressure steam heating system for vehicles - Google Patents

Description

H. APPEL March 16, 1948.

LCM-PRESSURE STEAM HEATING SYSTEM FOR VEHICLES Filed Jan. 16, 1941 ,1 fil /Mi" Hans 4pp M! I @L After-nay Patented Mar. .16, 1948 LOW-PRESSURE STEAM HEATING SYSTEM FOR VEHICLES Hans Appel, Prague, Germany; vested in the Attorney General of the United States Application January 16, 1941, Serial No. 374,611 In Czechoslovakia December 24, 1938 2 Claims. 1

The present invention relates to a completely automatic, self-contained, low-pressure steam heating plant for vehicles.

-It is an object of this invention to provide a plant of the class described having control means which interrupts combustion at a predetermined steam pressure in the boiler, which interruption, in turn, acts to lower the pressure. Such combustion control may comprise a membrane member which is operatively connected with the fuel and/or air supply means to control said means.

The combustion control preferably operates in combination with water replenishing and associated steam releasing devices. The water replenishing device may comprise a float member and a water supply valve operated thereby, and the associated pressure releasing device may comprise a stand pipe connected to the water space of the boiler at the point oi the minimum permissible water level, which pipe releases the boiler pressure when the water level in the boiler reaches a predetermined minimum level. Where a relatively high boiler pressure must be maintained, the stand pipe is also provided with a valve or closure member controlled by the float device, which valve is opened as soon as the minimum permissible water level is reached to release the steam pressure through the stand pipe.

The stand pipe closure member "allows said membrane, or pressure sensitive control member influencing the furnace, to maintain a regulated steam pressure in the boiler as long as the closure member is closed and the wa er level in the boiler lies between the permissible maximum and minimum limits. In such an instance the steam pressure in the boiler may be higher than the column 01' water in the stand-pipe.

It is another object of this invention to 'provide a low-pressure steam generating and heating plant for vehicles, saidplant being characterized by great simplicity, reliability, and ease of operation.

To obtain these objects, a steam generating plant, automatically controlled as far as the steam generation and the water supply are concerned is used, not only to provide the radiators with heating steam, but to also simultaneously control the temperature of the heating surfaces of the radiators connected to the steam generating plant. To this end the radiators are so. connected to the steam space of the boiler of the steam generating plant that their interior spaces and the steam space of the boiler form a closed space in which the same steam pressure prevails at all places. Moreover, the above mentioned apv Fig. 1.

paratus is provided at the boiler for automatically controlling this steam pressure and thereby automatically controlling the temperature of the heating surfaces of the radiators connected'to the boiler. In this manner special devices which hitherto were required for controlling the steam supplied to the radiators and maintaining uniform the temperature of the heating surfaces of the radiators are rendered superfluous.

In the accompanying drawings a heating system according to the invention 01' example.

In these drawings:

Fig. 1 is a diagrammatic lay-out of a lowpressure steam heating plant according to the invention, and

Fig. 2 is a sectional view is shown by way of a detail shown in In the heating plant shown in Fig. 1 a'lowpressure steam boiler I, embedded in refractory bricks, is mounted upon suitable beams of the vehicle, for instance below the floor. At the elevation of the selected minimum water level, a U-shaped stand-pipe I extends downwardly and then leads out 01' the water space of the boiler i and then upwardly above the water level of water tank 24 mounted below the roof of the vehicle. A second pipe 4 extends upwardly from the water space 01' the boiler and discharges into the bottom of storage tank24 and forms part of a water feed pipe or replenishing system for the boiler.

This pipe 4 is controlled by a closure member or piston 3 actuated by a float 2 which, on reaching the maximum water level in the boiler I, closes the passage through pipe 4. Therefore, as long as the water is below the maximum level in the boiler and the prevailing pressure permits, water will flow from the higher located tank 24 by way of the pipe 4 into the boiler i. Whenever the maximum water level is reached, pipe 4 is closed. Up to this time the diiference between the water level in the highly located tank 24 and the water level in the boiler determines the pressure in the boiler. If the replenishing pipe 4 is closed, the boiler pressure is determined by the column 01 water in the stand-pipe 5 as long as closure member 6, interposed in the pipe system leading from the boiler by way of the-stand-pipe 5 into the atmosphere is open. a

The boiler I is heated with liquid fuel which is supplied from higher located fuel tank 25 to burner 29 by way of a pipe 21. The necessary combustion air may be supplied by a blower H) which may be electrically driven and connected to the burner 29 by the pipe bend shown.

' boiler I.

The steam space of the boiler I is connected, by means of the pipes lI, I8, to the radiators I9 which, when the inlet valves are opened by the setting levers 2 I, are all filled with steam ofthe same pressure as that of the boiler, whereby the temperature of their heating surfaces is maintained corresponding to the steam pressure controlled by the height of stand-pipe 5.

With a larger number of radiators the pressure limited by the water in the stand-pipe is not sumcient. For this'purpose a closure member 8, i. e. a piston, is arranged in the pipe system leading to the stand-pipe] from the boiler I which piston is connected to the closure member 3 in such a manner that on reaching the predetermined minimum water level in the boiler piston I closes the passage to the stand-pipe 5.

When the heating system is in operation, piston 4 closes the passage leading from the boiler by way of the stand pipe I! into the atmosphere and a bellows I4, filled for instance with glycerine, is provided to regulate the steam pressure in the On being compressed, bellows I4 feeds glycerine by way of pipe I3 to a spring loaded piston in cylinder I2 which is moved thereby and swings a lever I4? In Fig. 2 of the drawings the cylinder I2 and the lever II are shownin detail and in section and side elevation respectively. By this arrangement the burner is so controlled and the firing or the boiler I is so influenced that a predetermined pressure is maintained in the boiler which assures the supply of all radiators connected to the boiler with steam.

In the stand-pipe I a throttling memberJI, for instance in the form of a helically wound small tube, not shown in the drawings, may be inserted which ofl'ers less resistance to the passage of steam than to the passage of water. It the pressure in the boiler rises while the passage to the atmosphere by way of the stand-pipe 5 is open, that is, while the piston 8 is drawn upwardly, water may be forced up through the stand-pipe I and into tank 24. If the water level in the boiler I is dropped to a predetermined minimum, steam only is discharged through stand-pipe I and nearly no resistance is caused by the throttling member 22 to the passage of this steam, so that atmospheric pressure is quickly reached. and the re-fllling operation with water from the higher located tank into the boiler isinitiatedas'follows: I

The drop of the water level causes a drop of the float 2 and thereby an opening of valves 3 and 4 and flow of water from the tank 24 by way of the pipe 4 into the boiler I whereby the development of steam in the boiler is reduced which accelerates the refilling operation.

If the permissible maximum water level is reached, the closure members 3 and 8 are closed again and the steam pressure in the boiler rises. As soon as this pressure has reached a predetermined value, the supply of fuel oil to the burner is interrupted by the pressure control member I4 acting by way of the piston arranged in the cylinder I2 and the lever I8. In this manner the required in the passage leading from the boiler by way of the stand-pipe 5 into the atmosphere and the pressure in the boiler and in the radiators is controlled by the column of water in the standpipe 5, whereby for assisting this pressure regulation a control device for the fuel may be provided in the form of a bellows or diaphragm box I4 which influences the burner 29. The regulating operations are eflected as follows:

If the boiler pressure has reached a predeter- ,mined value the supply of oil to the burner is interrupted by the pressure control I4, I2, and I8, the burner, however, continuing to burn for several seconds. In this moment the water pressing upwardly in the stand-pipe 8 overcomes the resistance of the throttling member 22, and water flows into the tank 24. The float 2 drops. Thereby, in the manner already described, water is discharged from the tank 24 into the boiler, the pressure drops. the controlI4, I 2 and I8 again effects opening of the fuel supply and the burner 29 is ignited by a pilot flame. If the water level in the boiler I'drops below the predetermined minimum value, 1. e. below the top a: of the leg of the standpipe I inside the boiler, then, after pressing of the water out of this tube into the tank 24, steam flows into the atmosphere above the tank, whereby the pressure in the boiler quickly drops and water speeds into the boiler through conduit 4., If the boiler should exceed the highest permissible limit, a safety valve 33 is opened which is provided in the steam main 3i leadingtothe radiators I 8.

I To increase the reliability of the heating plant which depends on a sufllcient quantity of water always being available in the higher located tank 24, condensed water from the radiators I9 is conpressure in the boiler I and in the radiators I9 connected thereto is regulated by the pressure ducted to a collecting tank I5, and pumped by means of pump II through conduits 36 and 35 into tank 24. i

A closure member 9 is mounted in the steam main 3| for centrally closing or disconnecting all radiators I I. For further safety a drain valve 1 at the bottom of the boiler I, and an outlet valve 8 arranged at the lowest point of the water return feeding pipe system 2! may be provided. The flow of water from the tank 24 may be diverted by manipulating 2-way valve 23 provided in the boiler feed pipe system 4, if it is intended to have this water available for other purposes.

As it sometimes happ ns that the vehicle provided with this heating plant is to be arranged in a train which is drawn by a steam locomotive supplying the heating devices oi all cars with steam, the closure member S is constructed as a two-way valve in such a manner, that this valve 9, when closing steam pipe 3i towards the boiler I, connects the radiators I9 by way of a branch pipe 32 to a pipe 30 located below the vehicle and to the main steam pipe of the train.

What is claimed is:

1. A low pressure steam heating system for vehicles. comprising, in combination. a small water capacity steam boiler disposed on the vehicle, radiators, a steam main interconnecting said boiler and said radiators, an automatic heat supply mechanism connected with said boiler for supplying heat thereto and including boiler pressure responsive means controlling the heat supply in accordance with the boiler pressure, a feed water storage tank located in the vehicle above the elevation of said boiler, a conduit connecting the water space or said tank with the water space of said boiler, valve means in said conduit, water level responsive means connected with said boiler acamva and with said valve means and opening said valve means when the water level in said boiler has reached a predetermined minimum and closing said valve means when the water level in said boiler has reached a predetermined maximum, and a U-shaped stand pipe having a shorter branch extending from the bottom of the boiler upwardly in the water space of the boiler to the minimum permissible water level, and a longer branch extending from the bottom of the boiler to a level in the storage tank above the water level in said tank. l

2. A low pressure steam heating system for vehicles, comprising, in combination, a small water capacity steam boiler disposed on the vehicle, ragiators, a steam main interconnecting said boiler and said radiators, an automatic heat supply inechanism connected with said boiler for sup- !{Jlying heat thereto and including boiler pressure responsive means controlling the heat supply in accordance with the boiler pressure, a feed water storage tank located in the vehicle above the elevation of said boiler, a conduit connecting the water space of said tank with the water space of said boiler, valve means in said conduit, water level responsive means connected with said boiler and with said valve means and opening said valve means when the water level in said boiler has reached a predetermined minimum and closing said valve means when the water level in said boiler has reached a predetermined maximum, a

one of its arms located outside said boiler and above the elevation of the water level in said tank, the end of the other arm of said U-shaped stand pipe communicating with the interior of the boiler at a point substantially coinciding with said predetermined minimum water level, and valve means disposed in said stand pipe and being operatively connected with said water level responsive means and being opened when the water level falls below a predetermined minimum and being closed when the water level rises above the predetermined minimum elevation, the conduit, stand pipe, their respective valves and the water level responsive means being so designed and related that when the water level in the boiler reaches its predetermined minimum both the conduit and the stand pipe are opened, so that water can flow from the tank to the boiler through the conduit, and from the boiler to the tank through the stand pipe.

U-shaped stand pipe connected with the water space or said boiler and having the upper end of HANS APPEL.

REFERENCES crrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,125,839 Wasson et a1 Aug. 2, 1938 2,162,337 Kriechbaum June 13, 1939 2,103,178 Raymond Dec. 21, 1937 315,160 Pentecost Apr. 7, 1885 41,504 Hammond Feb. 9, 1864

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