US2293548A - Pressure gas generator - Google Patents

Description

Aug. 18, 1942- J. E. JOHANSSON PRESSURE GAS GENERATOR W Filed March 25, 1940 nl i In aeni'or: Johan Ez c'it Ibiza Ewan, WQQJSIKVQ A-Z'C yc.

I NW

Patented 18, 1942 Johan Erik Johansson, Goteborg, Sweden,

or to Aktiebolaget Giitaverken,

assign- Goteborg.

Sweden, a corporation of Sweden Application March 25, 1940, Serial No. 325,898

In Sweden March 31, 1939 6 Claims.

The present invention relates to improvements in pressure gas generators comprising internal combustion engines and air compressors driven thereby. In such pressure gas generators the compressed air produced by said compressors and the partly expanded exhaust gases of the internal combustion engines form the pressure gas. Now, as a result of the air compression in known generators of this type it sometimes happens, that the compressed air produced by the compressors reaches a temperature, which is so high that oil, which may gather at the air inlet openings of thecylinders of the internal combustion engines or at other points, is ignited, when it comes into contact with the hot compressed air. In order to avoid the danger and disadvantages connected with this circumstance it has been proposed to cool down the entire air quantity produced by the compressors before said air is admitted to the cylinders of the internal combustion engines, which, however, results in a considerable reduction of the thermodynamic efliciency of the air production.

One object of the invention is to increase this efllciency.

Another object of the invention is to combine the compressors and internal combustion engines of a pressure gas generatorof the abovementioned type so as to form a more concentrated and convenient construction.

A further object of the invention is to provide means for equalizing the temperature of the compressed air admitted to'the internal combustion cylinders.

With these and other objects in view I provide means for intermediate cooling of a stepwise compressed portion of the air produced by the compressors. Further features of the invention are set forth in the following specification and claims.

In the accompanying drawing one embodiment of the invention is illustrated by way of example.

Fig. 1 is a side sectional view of a pressure gas generator according to the invention.

Fig. 2 is a cross section on line II-II in'Fig. 1.

Fig. 3 is a cross section on 1ineIIIIII in Fig. 1, and x Fig. 4 is a section on line IV-IV in Fig. 1.

In the drawing l designates the lower half and 2 the upper half of a crank case of a pressure gas generator comprising an internal combustion engine and air compressors driven thereby. The internal combustion engine may naturally be of any type operating on the two or multiple stroke principle and having any number of cylinders,

pistons l3 and I 4, respectively,

and in the present embodiment of the invention a two stroke Diesel engine is illustrated comprising two Diesel cylinders 3, inwhich opposed motion pistons 4 ahd 5 are provided. The air compressors driven by the internal combustion engines may also be of any suitable type such as reciprocating compressors, rotating compressors or the like, at least one of which is working with stepwise compression. The drawing shows two one step and one two step reciprocating compressors. The pistons 4 of the Diesel engine are connected or preferably integral with compressor pistons 8 operating in compressor. cylinders l of single acting one step compressors arranged on top of the internal com bustion cylinders 3. .The pistons 4 and 5 are connected by means of connecting rods 8 and 9, respectively, to a crank shaft l0 mounted in the crank case I. A further connecting rod II is connected to the crank shaft I0 and by means 'of a piston rod [2 with two pistons l3 and ll of a two step double acting reciprocating compressor. In the present case said two step compressor produces approximately one third of the total air quantity delivered by the air compressors comprised in the pressure gas generator. The two step compressor consists in a large cylinder I5 and a small cylinder I 6, in which the operate. The cylinder I5 is provided with automatic inlet valves l1 and automatic outlet valves l8 and anoutlet chamber I 9 common for both ends of the low pressure compression cylinder and serving to conduct the air compressed in the cylinder l5 to an intermediate cooler 20, which may be of any suitable type and in the illustrated embodiment is a tubular cooler, to which cooling medium is supplied through a connection 2| and from which the cooling medium is led away through an outlet 22. From the cooler 20 the air flows to an inlet chamber 23 common for both ends of the high pressure cylinder 16. cylinder I6 is provided with automatic inlet valves 24 and automatic outlet valves 25 and an outlet chamber 28 common for both ends of the high pressure cylinder I 6. The air, which has been cooled down to a considerable extent in the intermediate cooler 20, is compressed in the cylinder I 6 to about the same pressure as the air compressed by the compressor pistons 6 in the cylinders 1, for instance, 4 to 5 kg./cm. above atmospheric pressure. The compressed air from the two step compressor flows from the outlet chamber 26 through a conduit 21, which is also connected with outlet chambers 28 of the The high pressure one step compressor cylinders I. 29 designates the inlet chambers of the compressor cylinders TI and 30 and 3| automatic inlet valves and automatic outlet valves, respectively, or the compressor cylinders "I. The air produced by the one step compressors I is mixed in the conduit 21 with the air produced by the two step compressor'15, it, which has previously been cooled down in the intermediate cooler 20 and consequently has a lower temperature than the air produced in the one step compressor cylinders I.

In order that the mixture or the diflerent air quantities shall obtain a uniform temperature before the air reaches the internal combustion cylinders 3 a device 32 for equalizing the temperature of the compressed air is connected between the conduit 21 and a conduit 33, which is connected to the inlet openings 34 o! the internal combustion cylinders 3. The temperature equalizing device 32 consists in a sheet metal drum enclosing a pack of corrugated sheet metal 35 or other suitable heat exchange bodies with large heat exchange surfaces and preferably good heat conductivity. The air, which has the highest temperature, gives ofl heat to the heat exchange bodies upon passage of the temperature equalizing device and said bodies give oil heat to the cooler portions of the air passing the device so that the air, which leaves the temperature equalizing device, is of substantially a medium temperature corresponding to the temperatures and quantities of compressed air produced by the compressors 1 and l5, IS.

The compressed air produced by the compressor serves as charging and scavenging air for the internal combustion cylinders and is mixed with the partly expanded exhaust gases, which are expelled from the motor cylinders at substantially the same pressure as the pressure of the compressed air through outlet openings 36 and a conduit 31, which is the delivery conduit oi the pressure gas generator. Fuel is supplied to the internal combustion cylinders by fuel pumps 33 driven from the crank shaft ill by means of a chain drive 39 and connected with conventional fuel injection valves 40 through pipes ll. The output of the internal combustion engine comprised in the illustrated pressure gas generator may be .completely utilized for driving the compressors comprised in the generator or a portion of the output of the internal combustion engine may be utilized for other purposes.

It is understood that my invention is by no means limited to the embodiment above described and illustrated in the drawing, which should only be considered as an example, and the invention may naturally be modified in several different ways within the scope of the following claims. The pressure gas generator may naturally be of a type, in which a portion of the compressed air does not pass the motor cylinders but is admixed to the exhaust gases of the motor when said gases are already expelled from the motor. In such a generator :3, direct communication may be provided between the delivery conduit of one or all compressors and the delivery conduit of the generator and suitable valves may be provided in said conduits to ensure the desired operation. Thus, as shown in Figures 1 and 2, a passage or conduit 50 is arranged to communicate the conduit 33 with the conduit 31. A casing 5| on the pipe or passage 53 houses a valve (not shown), and a handle 52 is connected to the? valve for controlling the flow of the air throug the passage 53.

What I claim is: 1. In a pressure gas generator, an internal combustion engine, an air compressor without inter-stage cooling driven bysaid internal combustion engine, a multi-stage air compressor driven by the internal combustion engine, a common delivery conduit for said compressors communicating with the combustion. cylinders oi the internal combustion engine, and an interstage cooler between. two steps in said multistage compressor, the compressed air from said compressors and the partly expanded exhaust gases of the internal combustion engine forming together the pressure gas produced by said pressure gas generator.

2. In a pressuregas generator, a reciprocating,

'duced by said generator.

3. In a pressure gas generator, a reciprocating internal combustion engine, opposed motion pistons in said internal combustion engine, a crank shaft, connecting rods connecting said crank shaft and said opposed pistons, a two step reciprocating air compressor operated by means of a connecting rod connected. to said combustion engine, air compressors driven by said internal combustion engine, at least one of said air compressors having means for stepwise compression of the air passing through said compressor, a communication between two steps of said stepwise compressor, a cooling means provided in said communication and adapted for intermediate cooling of the air passing said stepwise compressor, said stepwise comm'essor being arranged to produce about one third of the compressed air produced by all comnressors of said generator, and a common delivery conduit for said compressors communicating with the combustion cylinders of the internal combustion engine, the compressed air of said compressors and the exhaust gases of the internal combustion engine forming together t e pressure gas produced by the generator.

5. In a pressure gas generator, an internal c mbustion engine. air compressors driven by said internal combustion engine, at least one of said compressors'having means for stepwise compression of the air passing through said compressor, a communication between two steps of said stepwise compressor, a cooling means in said communication adapted for intermediate cooling. of the air passingthrough said communication, a delivery conduit communicating with said compressors and the internal combustion cylinders, and a temperature equalizing desaid internal combustion engine, at least one of said air compressors having beans for stepwise compression of the air passing through said compressor, a communication between two steps of said stepwise compressor, a cooling means in said communication adapted for intermediate cooling of the air passing through said communication, aconduit communicating with the air compressors and the internal combustion cylinders, a temperature equalizing device in said conduit between the compressors and the internal combustion cylinders, and heat exchange bodies in said device, the compressed air of said compressors and the exhaust gases of the internal combustion engine forming together the pressure gas produced by said generator.

J OHAN ERIK J OHANSSON.

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