Fluid handling – Systems – With pump
Reexamination Certificate
2002-08-19
2004-10-05
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Systems
With pump
C060S412000
Reexamination Certificate
active
06799601
ABSTRACT:
The current invention relates to a device for at least intermittently generating an overpressure in a system in relation to an ambient pressure, with a pump that has a pressure side and an intake side, where during the generation of an overpressure, the pressure side is connected to the system and the intake side is connected to the ambient pressure by means of at least one first valve, in particular a solenoid valve, and the first valve throttles the intake volume flow due to its cross section. Furthermore, the current invention also relates to a valve, in particular an additional valve for the device according to the invention, with a valve inlet and a valve outlet that can be connected to each other.
Devices of this generic type include, for example, devices that are provided for connecting the pressure side or the intake side of a compressor or pump to a system by means of two solenoid valves in such a way that either an overpressure or a vacuum can be generated in the system. Known devices suitable for this are shown in
FIGS. 1 and 2
.
FIG. 1
shows a device that has a compressor or pump P with an intake side
10
and a pressure side
20
. The pressure side
20
of the pump P is associated with a check valve R, which is connected by means of an output L
2
to the pressure side
20
of the pump P. The device shown is provided for generating an overpressure or a vacuum in a system S. To this end, a first solenoid valve MV
1
and a second solenoid valve MV
2
are provided, by means of which the pump P can be connected to the system S in a suitable fashion. The first solenoid valve MV
1
and the second solenoid valve MV
2
are shown in their respective neutral positions. In this neutral position, the system S is connected to the ambient pressure by means of a line L
7
, the second solenoid valve MV
2
, a line L
4
, a line L
5
, the first solenoid valve MV
1
, and a line L
8
.
In order to generate an overpressure in the system S shown in
FIG. 1
, the second solenoid valve MV
2
is switched. As a result, the system S is connected to the pressure side
20
of the pump P by means of the second solenoid valve MV
2
, the line L
3
, the check valve R, and the line L
2
. In the switched position of the second solenoid valve MV
2
, the line L
4
is closed by the second solenoid valve MV
2
. The line L
6
is likewise closed by the first solenoid valve MV
1
, which is in its neutral position. During overpressure operation, the intake side
10
of the pump P is connected to the ambient pressure U by means of a line L
1
, a line L
5
, the first solenoid valve MV
1
, and a line L
8
.
In order to generate a vacuum in the system S shown in
FIG. 1
, the first solenoid valve MV
1
is switched out of the position shown in
FIG. 1
, while the second solenoid valve MV
2
remains in the neutral position shown in FIG.
1
. In this position of the first solenoid valve MV
1
, the line L
5
is closed by the first solenoid valve MV
1
, while the line L
6
is connected by the first solenoid valve MV
1
to the line L
8
and therefore to the ambient pressure. As a result, the pressure side
20
of the pump P is connected to the ambient pressure by means of the line L
8
, the first solenoid valve MV
1
, the line L
6
, the line L
3
, the check valve R, and the line L
2
. The system S is therefore connected to the intake side
10
of the pump P by means of the line L
7
, the second solenoid valve MV
2
, the line L
4
, and the line L
1
. As mentioned above, in the generic device according to
FIG. 1
, the system S is connected to the ambient pressure U when the first solenoid valve MV
1
and the second solenoid valve MV
2
are in their neutral positions.
By contrast, in the likewise known device according to
FIG. 2
, the system S is sealed when the solenoid valves are disposed in their neutral positions, as will be explained in detail below. The device according to
FIG. 2
also has a pump P with an intake side
10
and a pressure side
20
. The pump P is once again associated with a check valve R, which is connected by means of a line L
12
to the pressure side
20
of the pump P. The system in which the overpressure or vacuum is to be generated is once again labeled with the reference letter S and the ambient pressure is once again labeled with the reference letter U. The device has a first solenoid valve MV
1
and a second solenoid valve MV
2
, whose respective neutral positions are shown in FIG.
2
. In these neutral positions, the line L
17
is closed by the second solenoid valve MV
2
while the line L
15
is closed by the first solenoid valve MV
1
. As a result, the system S is sealed in the neutral position of the first solenoid valve MV
1
and second solenoid valve MV
2
.
In order to generate an overpressure in the system S with the device according to
FIG. 2
, the second solenoid valve MV
2
is switched, while the first solenoid valve MV
1
remains in the neutral position shown in FIG.
2
. When the second solenoid valve MV
2
is switched, the system S is connected to the pressure side
20
of the pump P by means of the line L
17
, the second solenoid valve MV
2
, the line L
13
, the check valve R, and the line L
12
. The line L
15
is closed by the first solenoid valve MV
1
and line L
14
is closed by the second solenoid valve MV
2
. During overpressure operation, the intake side
10
of the pump P is connected to the ambient pressure U by means of the line L
11
, the first solenoid valve MV
1
, and the line L
16
.
In order to generate a vacuum in the system S with the device according to
FIG. 2
, the first solenoid valve MV
1
is switched out of the position shown in
FIG. 2
, while the second solenoid valve MV
2
remains in its neutral position. As a result, the system S is connected to the intake side
10
of the pump P by means of a section of the line L
17
that is closed by the second solenoid valve MV
2
, the line L
15
, the first solenoid valve MV
1
, and the line L
11
. During vacuum operation the pressure side
20
of the pump P is connected to the ambient pressure U by means of the line L
12
, the check valve R, the line L
13
, the second solenoid valve MV
2
, the line L
14
, and a section of the line L
16
that is closed by the first solenoid valve MV
1
.
One disadvantage of the known devices shown in
FIGS. 1 and 2
lies in the fact that the intake volume flow is throttled by the respective intake-side first solenoid valve MV
1
, as a result of which the compressor or the pump P achieves a lower pneumatic output. One obvious solution to this problem, namely to avoid the undesirable throttling of the intake volume flow by providing the intake-side solenoid valve with a sufficiently large cross section, entails other problems. A valve of this kind with a sufficiently large cross section requires large dimensions, is heavy, and is therefore expensive. Furthermore, in many cases it is desirable to use identical or similar valves on both the pressure side and the intake side.
SUMMARY OF THE INVENTION
Because the device according to the invention has means for providing an additional cross section for the intake volume flow during the generation of an overpressure, a higher pneumatic output can be achieved with the pump. Furthermore, the dimensions and weight of the first valve do not have to be increased and if a second valve is provided, identical or similar first and second valves are used.
A preferred embodiment of the device according to the invention provides that the means include at least one additional valve, which is connected in parallel to the first valve during the generation of an overpressure. As a result, the total cross section available for the intake volume flow can be increased by the cross section of the additional valve.
Particularly when the first valve is a solenoid valve, it is preferable that the additional valve be opened by an overpressure generated in the system. As a result, it is not necessary to provide additional energy sources for actuating the additional valve, but it is sufficient, for example, to connect a line leading to the system or the system i
Bauer Bertram
Merz Harald
Paessler Wolfgang
Michalsky Gerald A.
Robert & Bosch GmbH
Striker Michael J.
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