Mechanical device for deactivating a suction pump on fire brigade pumps

Abstract

Mechanical device for shutting down the suction operation of an automatic suction pump, which normally shuts down via hydraulics or pneumatics.

Description

[0001] The following refers to a mechanical device which ensures that the automatic suction, for example on a fire brigade portable pump, can be deactivated for a special application.

[0002] The portable fire pump requires a priming pump to pump water from the suction point, such as a well, to the main pump. Without this priming, the main pump would not receive any water, as it is not self-priming. Depending on the manufacturer, each portable pump has a different priming pump design. These are either connected directly in series with the main pump or can be operated, switched on, and off, in parallel via connecting devices, such as couplings.

[0003] For pumps where the priming pump runs in series with the main pump, it cannot simply be shut down. However, the priming pump must be shut down once the priming process is complete to prevent it from continuing to run. The water pressure in the main pump housing is used as an indicator of whether the priming process is complete.

[0004] Either the water pressure itself or a pneumatic device is used as the working medium to deactivate the suction pump. In these versions, where water pressure is used as the working medium, the suction pump contains a piston and diaphragm. The pistons move linearly, guided by piston rods, and the sucked out air and water are passed through these pistons via inlet and outlet diaphragms. The movement of the pistons is usually achieved by an eccentric which converts the rotary movement of the pump shaft into a linear movement of the piston. If the water pressure increases, the pistons move further outwards and the engagement of the eccentric on the piston or piston rod decreases, and with it the piston stroke. Once a certain water pressure is reached, the pistons move outside the engagement of the eccentric and are no longer driven.In addition, springs press on the outlet diaphragm, preventing further water loss through the pistons. If the water pressure drops below a defined level, the pistons return to the engagement zone of the eccentric and are driven again. These priming pumps feature automatic priming.

[0005] For applications where low water pressure is required, so-called bilge pumping, the problem can arise that the pressure drops below the limit pressure at which the pistons are no longer driven. The pistons then rotate continuously. Even in applications where water is not being sucked in but rather fed in, the eccentric rotates briefly with the pistons. This is common in firefighting sports, for example, and is undesirable. In both cases, the pump's rotation can cause damage to the suction pump.

[0006] The innovation is that the pistons can be pulled out of the engagement zone of the eccentric by a mechanical device, where they remain until they are brought back into the engagement zone. This pulls the pistons outward far enough that they are in the end position, as in automatic operation, and the diaphragms are also closed by the springs. When they are brought back into the engagement zone, they function automatically again, as before.

[0007] The application already requires the pistons to be moved outside the engagement zone by injecting compressed air into the space behind the piston, thus simulating the defined water pressure limit. This pushes the piston outside the engagement zone. However, this principle only works where compressed air is available, for example, in a fire engine. This is not possible for load-bearing peaks that do not have a pneumatic system.

[0008] The innovation consists of a pulling device which contains at least one limit stop, for example a pull rod in which another linearly movable rod is located. The movable rod moves in the direction of the eccentric and cannot be pulled out of the pull rod. Advantageously, the movable rod can be pushed into the pull rod to the maximum stroke of the eccentric. The current installation position of the pull rod can be repositioned, for example using a thread or an electromagnetic device. By screwing the pull rod out, away from the eccentric, the stop of the inner movable rod is pulled outwards. The piston of the suction pump is attached to the movable rod. As long as the pull rod is screwed towards the eccentric, the piston can fully follow the movement of the eccentric and can also be pushed outside the engagement zone by the water pressure - the desired automatic operation.The movable rod slides back and forth within the pull rod. If the pull rod is unscrewed from the eccentric, the position of the stop on the inner movable rod also changes, thus limiting the piston's engagement zone with the eccentric. When the pull rod is unscrewed as far as it will go, the piston no longer engages the eccentric, and the suction pump is disabled.

[0009] This innovation makes it possible to deactivate the suction function without pneumatics or hydraulics. The user can do this manually, for example, allowing water to be pumped at low pressure or to suppress the suction function. List of reference symbols 1 eccentric on pump shaft 2 pistons with piston rod to the eccentric 3 Connecting rod to the piston 4 Positioning device with stop 5 Housing of the intake device 6 Outlet membrane 7 springs for closing the outlet diaphragm 8 Piston return spring 9 Housing with pump shaft

Claims

[1] Mechanical device for shutting down the suction operation of an automatic suction pump, which normally shuts down via hydraulics or pneumatics. [2] Mechanical device, characterized by that there are at least two operating positions: the desired automatic suction mode, and the deactivation of the suction mode. [3] Mechanical device, characterized by that the shutdown is not carried out hydraulically or pneumatically. [4] Mechanical device, characterized by that it is coupled to the piston and the end position of the piston can be specified by another device with at least one stop.

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