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Valve device and piston mechanism provided with such valve device. This invention relates to a valve device comprising at least two valves with a body and a seat.
Such a valve device is used inter alia in piston mechanisms, in which two valves are arranged next to each other in the head of the cylinder, which valves can close off an inlet line and an outlet line respectively.
In the open position, each valve has an annular passage formed between the valve body and the seat formed in the cylinder head. The outer diameter of these annular passages is limited to less than half the diameter of the cylinder, which means that the size of the passages of the valves is quite limited, regardless of their lifting height.
The invention has for its object to provide a valve device which overcomes this drawback and offers a larger passage than the aforementioned known valve devices and yet is relatively simple and inexpensive.
This object is achieved according to the invention in that the valves are arranged in each other, wherein the outer valve has a hollow body which is provided with a passage, a part of this body forming the seat for the inner body of the inner valve.
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The body of the outer valve is, for example, funnel-shaped.
Preferably the valves are concentric.
The valves can be arranged on the same line and, for example, replace a non-return valve. In such cases, only one valve is normally used. The valve device with at least two valves according to the invention makes it possible to increase the passage considerably without taking up more space as a whole.
Because the valve device comprises at least two valves, it can also be fitted on two different pipes, whereby one valve can close one pipe and the other valve the other pipe.
In this case, the hollow body of the outer valve which can close one of the lines must have a passage closable by the inner valve which forms part of the other line.
Preferably, the valves are then operated by a displacement mechanism that can lift their bodies from their seats, such as a cam mechanism.
Different fluids can flow through the two pipes, whether or not in the opposite sense.
In the latter case, the valve device may form part of a piston mechanism.
The invention therefore relates to a valve device which is characterized in that it is part
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constitutes a piston mechanism comprising at least one cylinder, a reciprocating piston reciprocating therein by means of a piston rod with a crankshaft, wherein at one end of the cylinder at least two pipes, a pressure pipe and a suction pipe on the inside of the cylinder. cylinder, wherein one valve of the valve device is an inlet valve on the suction line and the other valve an outlet valve on the discharge line.
Known valve devices mounted in a piston mechanism have an inlet valve and one outlet valve in the head of the cylinder, so that the passage through the valves, apart from their lifting height, is limited.
Because of this limited passage, a pressure drop is created that causes losses.
This disadvantage is avoided by the invention.
The outer valve can then have a diameter that is substantially equal to the diameter of the cylinder, while the inner valve can have a diameter that is substantially equal to the diameter of the mouth of the passage of the outer valve. The passages can thus be maximum and the losses minimal.
The inner valve can be the outlet valve on the delivery line and the outer valve then the inlet valve on the suction line.
The displacement mechanism is capable of directly or indirectly pushing both both valves together so that the outer valve is open and the passage in the outer
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valve is closed, if only the inner valve is pushed away separately, whereby said passage is open.
This displacement mechanism can be a camshaft that contains a cam per cylinder.
The piston mechanism can be a pump or an explosion engine.
Especially with explosion engines, the pressure losses caused by the limited passage have a negative effect on the power.
The invention also relates to a piston mechanism comprising at least one cylinder, a reciprocating piston which is connected to a crankshaft by means of a piston rod, wherein at one end of the cylinder at least two pipes, namely a pressure pipe and a suction pipe opening onto the inside of the cylinder via openings which can be separately closed by a valve device comprising an inlet valve on the suction line and an outlet valve on the pressure line, each comprising a body cooperating with a seat and which cooperate with a displacement mechanism, and which is characterized thereby is that the valves of the valve device are arranged in each other,
the outer valve having a hollow body, a portion of which forms the seat for the inner body of the inner valve and said outer valve which can close one of the pipes, has a passage forming part of the other pipe and passing through the lockable inner flap
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The piston mechanism can be an explosion engine and contain an ignition with at least one ignition pole inside the cylinder containing two cooperating contacts between which an electrical voltage can be applied.
In blast engines, large quantities of gases must flow in and out of the cylinders in a short time. In blast engines with a known valve arrangement, the aforementioned pressure losses occur both at the inlet stroke and at the outlet stroke, but due to the pressure drop on the valve in the suction line, in the short period of time that this valve is open, the maximum amount of air and possibly gas-fueled will never occur. can be sucked in and a shortage of freshly explosive mixture will occur.
This additional load loss also has a negative influence on the power of the engine.
The gas mixture must be exploded, theoretically at the end of the compression stroke and thus when the piston is in the upper dead center.
Since the explosion of the gas mixture cannot occur infinitely quickly, in practice the ignition is started earlier and thus a few degrees before the piston reaches the dead point. This deviation is also accompanied by a certain loss of capacity.
To limit the aforementioned losses, it is already known to use pre-outlet and post-inlet in blast engines by advancing the moment at which the inlet valve and the outlet valve are opened by about 450 on the crankshaft. This gives a better filling during the inlet, but losses during the outlet.
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Another known solution is to use compressors to increase the pressure on the inlet valve and thus improve the filling. The velocity of the gases at the outlet is used to drive this compressor.
Compressors or turbos, however, have a certain inertia and when starting an engine they start quite slowly. The compression by these compressors also causes a certain heating of the air, possibly with fuel, whereby the degree of filling is adversely affected. To remedy this, the air after the compressor must be cooled in a cooler, making these blast engines relatively expensive.
Also, four or even more valves per cylinder are often used to increase the passage of the inlet and outlet.
Such a solution is equally effective at all speeds, but the drive of the valves is relatively extensive and expensive. Usually two overhead camshafts are used per row of cylinders with a cam for each valve.
All these disadvantages are avoided by the blast engine with a valve mechanism according to the invention as described above.
Because of the construction of the valve device, this ignition pole can no longer be arranged centrally in the cylinder head as usual.
Hence, in a particular embodiment of the invention, the contacts of the ignition pole on the piston
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and / or are provided on one of the valves, preferably the interior.
A contact provided on the piston may be electrically isolated from the piston.
There are explosion engines with several spark plugs per cylinder or with spark plugs with several ignition poles, which allows a faster ignition and therefore a greater internal efficiency as a result.
For the same reason, several ignition poles according to the invention and thus several contacts can be arranged on the piston and / or on a valve.
With the insight to better demonstrate the characteristics of the invention, a preferred embodiment of a valve device and a piston mechanism provided with such a valve device according to the invention is described below as an example without any limiting character, with reference to the accompanying drawings, in which: figure 1 schematically represents a valve device according to the invention; figure 2 represents a section of a piston mechanism according to the invention; Figures 3 to 5 show cross-sections analogous to those of Figure 2, but with the valves in other positions.
The valve device shown in Figure 1 arranged in a pipe 1 consists of an inner valve 2 which is concentrically surrounded by an outer valve 3.
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This outer valve 3 comprises a hollow body 4, funnel-shaped and thus widening towards an end, which is internally provided with a passage 5 which increases in diameter at the said end and cooperates with an annular seat 6 which is on the inner wall of the conduit. 1 is formed and with which the outer edge of the widest end of the body 4 cooperates.
The inner valve 2 comprises a solid, slightly conical body 7 and cooperates with an annular seat 8 formed by the widest edge of the inside of the funnel-shaped body 4.
The body 7 merges with its top into a stem 9 which is provided with a collar 10 at its free end and which forms a guide for a ring or hollow stem 11 which is connected by arms 12 to the body 4 of the valve 3 .
The valves 2 and 3 are thus displaceable relative to each other, the stem 11 forming a stop, on the one hand, for the collar 10 of the stem 9 and, on the other hand, for the body 7.
When a flow occurs in line 1 in the sense represented by the arrow 13 in Figure 1, the body 7 is pressed against the seat 8 and while the body 7 remains against the seat 8, the body 4 is pressed against the seat 6 as shown in Figure 1.
With a flow in the opposite sense, the bodies 4 and 7 are pushed separately from their respective seats 6 and 8.
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The valve device thus acts as a non-return valve, but with a double and thus greater passage for the fluid when the flow is in the opposite direction to the arrow 13.
A spring can act on one or both bodies 4 and 7 which pushes these bodies 4 and 7 into either open or closed position when there is no or practically no flow.
Figures 2 to 5 show a piston mechanism that contains another embodiment of the valve device described above. Similar elements are designated with the same reference numeral.
The piston mechanism shown in these figures 2 to 5 forms part of a four-stroke gasoline engine and comprises a number of cylinders 14, of which only one is visible in the figures, with pistons 15 displaceable therein, each of which is connected by means of a piston rod 16 to a common crankshaft 17 arranged in a crankcase.
At one end, namely at the head of the cylinder 14, a first line 18 centrally issues on the inside of the cylinder 14, which is closable by the inner valve 2 of the valve device and a second line 19 opens around the mouth of the first line 18 on this inside, which second line 19 can be closed by the outer valve 3.
The passage 5 forms part of the first line 18 and the outer valve 3 forms a movable end of this line 18.
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In the example shown, the first line 18 is an outlet or pressure line and the inner valve 2 is the outlet valve.
The other line 19 is then, therefore, the inlet or suction line, while the outer valve 3 is the inlet valve.
The outer valve 3 has a diameter that is substantially equal to the diameter of the cylinder 14.
This valve 3 consists of a funnel-shaped body 4 widening in the direction of the inside of the cylinder 14 and thus provided with a passage 5 widening to this inside and of a hollow stem 11 which via arms 12 with the upper narrowest end of the body 4 is connected.
The inner valve 2 also consists of a body 7 which is generally conical in shape but is not open and of a stem 9 which extends displaceably through the hollow stem 11.
While the seat 6 for the body 4 of the outer valve 3 is formed by the portion of the head of the cylinder 14 that is located around the mouth of the suction line 19, this body 4 itself forms the seat 8 for the body 7 of the inner valve 2 which can therefore close the passage 5 through the body 4.
The difference between the inside diameters of the aforementioned seats 6 and 8 corresponds to the thickness of the widest end of the funnel-shaped body 4 and is relatively small.
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The body 4 therefore forms part of the conduit 18, of which it forms, as it were, a telescoping and extendable end. Hence, the arms 12 should of course not close the narrow end of the body 4.
Since the body 4, because it forms the effective part of the outer valve 3, is of course movable, while the actual pressure line 18 inside the head of the cylinder 14 is fixed and immovable, the narrow end must move during the movement of the outer valve 3. of the body 4 to remain in contact with the inside of the fixed part of the discharge line 18 to prevent leaks between this discharge line 18 and the suction line 19.
The upper part of the stem 11 of the outer valve 3 is provided with a thickened end 20. Between this thickened end 20 and the head of the cylinder 14, the stem 11 is surrounded by a spring 21 which pushes the valve 3 to the closed position and thus pushes the stem 11 outwards relative to the cylinder 14.
In the aforementioned closed position, this end 20 is situated in the path of a cam 22 which rests on a camshaft 23 extending above the cylinder 14 and forming a displacement mechanism for the valves 2 and 3.
The stem 9 of the outlet valve 2 also has a thickened end 24 at the location of said thickened end 20 of the stem 11 and within this stem 11 is a stem 9 between this thickened end 24 and an inwardly protruding collar 25 of the stem 11. surrounded by a spring 26 which pulls the body 7 towards the body 4 via the stem 9 and the stem
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9 with its end into a slot 27 which is arranged in the thickened end 20.
A lever 28 rests on this thickened end 24, one end of which is rotatably mounted by a pivot axis 29 on a support 30 which rests on the head of the cylinder 14, and the other end of which is bent over. This lever 28 also cooperates with the aforementioned cam 22. The pivot axis 29 is directed perpendicular to the shank 11 and parallel to the pivot axis of the cam shaft 23 and the lever 28 extends through said slot 27 in the thickened end 20.
The piston mechanism shown in the figures also contains in each cylinder 14 an ignition mechanism which, for the sake of simplicity, is only shown in detail in Figure 4.
This ignition mechanism consists of several, in the example shown, four ignition poles which are formed by pairs of co-operating and thus opposite contacts 31-32 between which a voltage difference is applied.
The contacts 31 connected to the voltage source not shown in the figures are recessed in the upper side of the piston 15 and insulated from the metal of the piston 15 by an electrically insulating mass 33.
The contacts 31 are connected via a conductive ring 34 to a main conductor 35 which extends to the underside of the piston 15 where it connects to a flexible current supply cable 36 for connection to a high-voltage source, not shown in the figures, namely a coil.
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The other contacts 32 which are connected to the mass of the cylinder 14 are arranged on the outside of the body 7 of the inner valve 2.
In one variant these contacts 32 can also be arranged on the piston 15, while in yet another variant all contacts 31 and 32 can be arranged on the body 7.
The operation of the piston mechanism described above is simple and as follows: During the intake stroke, as shown in Figure 2, the cam 22 of the camshaft 23 pushes both the thickened end 20 of the stem 11 and the lever 28, this lever 28 pushes the thickened end 24 of the stem 9 away.
The stem 11 is hereby pushed away against the action of the spring 21 and the stem 9 over such a distance that they remain in contact with each other during displacement, which means that the outer valve 3, and thus the inlet valve, opens but the other valve 2 continues to close the passage 5, and thus the discharge line 18.
The pivot axis 29 can be adjustable relative to the support 30, whereby the moment at which the lever 28 is pushed away by the cam 22 and thus the moment at which the inner valve 2 is pushed away can be changed.
In the meantime, the crankshaft 17, which is rotated twice as fast as the camshaft 23, moves the piston 15 in the direction shown by the arrow 37 in Figure 2, so that through the relatively large opening through the open outer
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inlet valve 3 is formed, air or a fuel-air mixture is sucked in.
When the piston 15 reaches its lower dead center, the cam 22 is no longer in contact with the thickened end 20, whereby the outer valve 3 is closed.
At the same time, the cam 22 is no longer in contact with the lever 28, as a result of which the inner valve 2 is displaced with the outer valve 3 and ultimately both valves 2 and 3 are closed.
The compression stroke now takes place and Figure 3 shows the position of the components during this compression stroke.
During this compression stroke, the piston 15 moves in the direction shown by the arrow 38 in Figure 3 and the explosive mixture is compressed.
When the piston 15 has reached its upper dead position, or just before, the ignition takes place and sparks jump between the contacts 31 and 32.
Due to the explosion, the piston 15 is pushed away in the direction indicated by the arrow 37 and the work stroke takes place as shown in Figure 4.
Due to the large number of ignition poles or contact pairs 31-32, multiple sparks are created at the same time, which means that the ignition is guaranteed and is extremely fast. The burning time will be quite short, which will increase the developed capacity.
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During this work or expansion stroke, the cam 22 is not yet active and the outlet and inlet valves 2 and 3 are still closed.
Even before the cam 22 comes into contact with the thickened end 20, it comes into contact with the bent end of the lever 28, whereby it is pushed away and the thickened end 24 is pushed away. Because the outer valve 3 remains stationary and only the inner valve 2 is pushed away, the mouth of the discharge line 18 opens with a large annular opening, as shown in Figure 5.
The combustion gases can now be pressed through this opening through the piston 15 which is displaced in the direction indicated by the arrow 38.
Because the valve construction generates relatively large passages both during the suction of the gas mixture and when pressing away the combustion gases, the pressure and charge losses are minimal. The operation of the valves is possible with a single camshaft and with one cam per cylinder, which makes the construction fairly simple.
The inner and outer valves do not necessarily have to be the outlet and the inlet valves. The reverse is possible, provided, of course, that the drive of the valves is adjusted.
This drive is only given as an example.
The camshaft can also act on the valve stem in other ways. Instead of a camshaft, a different displacement mechanism can be used, such as a system with hydraulic pistons.
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The construction of the valves described above can also be applied to injection engines, in which case only air is sucked in via the suction line 19, and in particular to diesel engines, in which case the ignition is of course omitted.
The number of valves that surround each other is not limited to two. Within the inner valve 2, for example, a third valve can also be arranged. A plurality of such valve structures consisting of two or more concentric valves can also be arranged next to each other.
The invention is even applicable to piston mechanisms other than explosion engines, namely piston pumps. Also in this case there is no ignition mechanism present.
The invention is in no way limited to the embodiment described above and shown in the figures, but such valve device and piston mechanism can be implemented in various variants without departing from the scope of the invention.