Pumps – One fluid pumped by contact or entrainment with another – Jet
Patent
1997-11-17
1999-09-21
Thorpe, Timothy S.
Pumps
One fluid pumped by contact or entrainment with another
Jet
417151, 417197, F04F 548
Patent
active
059544813
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a jet pumps, particularly for the operation of a vacuum brake booster of a motor vehicle.
Such jet pumps are used in a brake booster system with a vacuum brake booster to increase the vacuum in the brake booster connected with a underpressure generator. In known systems of this type, a sucking jet pump is used in a suction line leading from the brake booster to a underpressure generator, to reinforce, if needed, the suction performance of the underpressure generator. For this purpose, the underpressure generator is connected at its outlet to a feed connection piece which is located laterally with respect to the flow direction at the sucking jet pump. By the addition of the pressurized outlet air of the pressure generator to the sucking jet pump, the flow in the latter is accelerated and more vacuum is generated. In order to prevent a pressure equilibration between the underpressure generator and the volume of the brake booster, a return valve arrangement is provided between the brake booster and the sucking jet pump.
From German Patent DE 43 10 761, a jet pump is known, in which the return valve arrangement is connected in one construction unit directly to the sucking jet pump. For this purpose, the sucking jet pump is constructed as a single part with a bypass made of a synthetic material and fitted with a valve arrangement provided with a feed connection piece. If the suction performance of the sucking jet pump is to be varied, then a new construction unit must be constructed in its entirety.
The object of the present invention therefore is to propose a jet pump which can be adapted, without extensive effort, to different suction performances. Furthermore, the manufacture of the jet pump should be cost advantageous, while simultaneously preserving a high functionality.
SUMMARY OF THE INVENTION
This object is achieved by a sucking jet pump presenting a nozzle insert which is inserted in a duct, and which forms the flow duct with decreasing cross section.
The use of a nozzle insert in which the cross section decreases in the direction of the flow duct, makes it possible, with an otherwise unchanged sucking jet pump, to incorporate nozzle inserts having different suction jet duct cross sections, and thus to build, in a cost-effective manner, a multitude of different jet pumps with high performance. The use of the same external dimensions of the jet pump with different performance types simplifies the construction of the space for incorporation, in which the jet pump is to be used, for example, the engine space in a motor vehicle.
If the nozzle insert is a separate exchangeable component, then it is possible to use cost effective parts, rather than expensive parts made of expensive materials, which are guaranteed to be operational for the entire lifespan. It is possible to perform maintenance on the jet pump. In that process, simple components, such as the nozzle insert, can be replaced, and it is not necessary to replace the entire pump.
In this context it is advantageously possible to design the nozzle insert and the suction pipe insert as a preassembled unit, with mutual adaptation to each other, which can be inserted into the housing of the jet pump. However, it is also possible to insert the two parts separately.
In this context, at least one of the inserts (suction pipe inserts and/or nozzle inserts) is connected with positive locking to the duct, in which it is or they are inserted. This can advantageously be achieved by using a corresponding insert which presents projections and/or recesses which engage in corresponding recesses or with corresponding projections formed in the duct. The insert can thus be attached by a latching or clipping mechanism.
If the duct, in which the nozzle insert is applied, is cylindrical or unilaterally conical, then it does not present a narrowed section or only one narrowed section at the end, and consequently it is possible to manufacture the jet pump using the injection molding procedure with a single mol
REFERENCES:
patent: 1415406 (1922-05-01), Scanes
patent: 2275627 (1942-03-01), Hartman
patent: 3208399 (1965-09-01), Keller
patent: 4019834 (1977-04-01), Teodorescu
patent: 4759691 (1988-07-01), Kroupa
Baier Siegfried
Noone David
Wenig Peter
Gartenberg Ehud
ITT Manufacturing Enterprises Inc.
Thorpe Timothy S.
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