The invention relates to a cylinder piston arrangement according to the preamble of claim 1. Cylinder piston arrangements of this kind are represented on the relevant market, especially as high pressure water pumps.
An essential application for pumps of this kind is the pressure conveyance of water loaded with foreign particles, especially also abrasive granulates. Hereby are particularly high speed turbines with high working pressures in the range of a few hundred up to one thousand bar in demand. Therefore, the energetic as also the volumetric efficiency factor is of big importance.
Object of the invention is therefore the establishment of pumps respectively fluid engines, which stand out with high efficiency factors of the above-mentioned kind as well as with high durability. The solution of this object is defined by the features of the claim 1.
Further embodiments and variants, also such, which are not in any case realizable, result by the features and the combinations thereof, respectively by the combination of the subclaims, as the case may be by including facultative features or combinations thereof.
Axial extending tube diaphragm pistons with internal working chamber offer the basis for a robust construction with high wear resistance, also at the operation with abrasive fluids. Admittedly, hereby in general relative huge clearance volumes need to be kept because of constructive reasons, what affects the volumetric efficiency factor disadvantageously. Exactly this problem is solved by the invention, namely with the help of clearance volume displacers. Totaling, the invention renders therewith a widely optimized type of construction possible.
The invention will further be described under reference to embodiment examples shown schematically in the drawings. Herein show:
FIG. 1 a partial axial sectional view of a high pressure pump with a working piston accomplished as an axial extending tube diaphragm piston, with which an interfering into the working chamber and with the oscillating driving movement participating clearance volume displacer is clutched;
FIG. 2 a partial axial sectional view similar to FIG. 1, likewise with a working piston accomplished as an axial extending tube diaphragm piston, as well as with a clearance volume displacer, which is however arranged fixedly to the frame of the pump and interferes due to the oscillating driving movement of the working piston relatively to it into the internal working chamber of the axial extending tube diaphragm piston;
FIG. 3 a partial axial sectional view similar to FIG. 2, likewise with a working piston accomplished as an axial extending tube diaphragm piston with internal working chamber, as well as with a frame-fixed clearance volume displacer, but with different flow path of the working fluid;
FIG. 4 a partial axial sectional view similar to FIG. 3, likewise with a working piston accomplished as an axial extending tube diaphragm piston with internal working chamber, as well as with a frame-fixed clearance volume displacer, but with different flow path of the working fluid and with different valve arrangement, altogether resulting in a further reduced clearance volume;
FIG. 5 a time diagram of the feed pressure p (bar) for a working piston of a volumetric pump over the time t (msec), namely for a construction without clearance volume displacer; and
FIG. 6 a diagram according FIG. 5, but for a construction with clearance volume displacer. This latter depiction is basically valid not only for moveable, with the working piston clutched clearance volume displacers (see FIG. 1), but also for frame-fixed static clearance volume displacers, which interfere by movement of the working chamber into it (see FIGS. 2 to 4). This comes especially at the application of axial extending tube diaphragm pistons into consideration.
In the realization according to FIG. 1, a working piston provided with a axial extending tube diaphragm (shown in upper dead center position and denominated in the following shortly as ASK) clutched at its lower end with a here only by a downwards directed arrow schematically shown driving device AVO, which operates oscillatorily. The upper end of the axial extending tube diaphragm piston ASK is arranged frame-fixedly and surrounds an inlet valve EV, which is accomplished as a non return valve fed over inlet ducts ID. The downwardly extending, hollow cylindrical section Z of the axial extending tube diaphragm piston is supported axially slidable with a here not shown lubrication in a housing borehole HB. In the interior of the axial extending tube diaphragm piston ASK is formed an oscillating working chamber AR, from which a coaxial hoist duct FK leads to an also as non return valve accomplished outlet valve AV and to an outlet duct AK.
With the axial extending tube diaphragm piston ASK is connected on the side of the working chamber AR a basically cylindrical clearance volume displacer TK1, which is here shown in the upper dead center position and obviously results in a substantial reduction of the operative clearance volume.
For the determination of the operating mode of this construction, it is to be reverted to the already given depiction in the FIGS. 5 and 6.
There the time diagram shows in FIG. 5 a retarded increase of the feed pressure p for a working piston of a volumetric pump for a construction without clearance volume displacer. Accordingly retarded is the pressure loss at the end of the pumping cycle. Both imply a considerable reduction of the pumping volume related piston travel, i.e. of the volumetric efficiency factor. The reason therefore is the compressibility of the working fluid contained in the clearance volume.
On the other hand, the clearance volume displacer TK1 interfering accordingly to FIG. 1 into the working chamber AR causes the steepening of the pressure increase as well as the pressure loss, in total thus a substantial improvement of the volumetric efficiency factor.
At the embodiment according to FIG. 2, a frame-fixed clearance volume displacer TK2a is provided, which however interferes into the working chamber AR and causes a similar improvement of the volumetric efficiency factor due to the arrangement of the working chamber AR inside the axial extending tube diaphragm piston ASK and thus because of the relative movement given by the pump drive between the axial extending tube diaphragm piston and the clearance volume displacer TK2a. Outstanding advantageous is here however the reduction of moved mass due to the frame-fixed clearance volume displacer.
Inlet valve EV and outlet valve AV are accomplished analogously to the embodiment according to FIG. 1, but the connection between working chamber and outlet valve is given by this a longer coaxial duct CD inside the clearance volume displacer and inside the admission valve.
Particularly advantageously appears at this embodiment, that for the displacer is given an internal flow-through and an external circulation flow of the working fluid with a flow redirection in an opening or end area of the clearance volume displacer. By this, inter alia an extra intensive purging of the working chamber and the valves regarding accumulation of residues and impurities, but also of compression attenuating air enclosures after longer dead times is made possible.
In the embodiment according to FIG. 3, in turn is provided a frame-fixed clearance volume displacer TK2b, with the according dynamic advantages. At the same time, however it is achieved a maximization of the clearance volume displacement by the lapse of a relative long coaxial duct standing in connection with the working chamber. The outlet of the fluid happens from working chamber AR over cross-holes CH directly below the inlet valve EV as well as a short and thus practically innocuous longitudinal duct LK.
In the embodiment according to FIG. 4, it is also provided a frame-fixed clearance volume displacer TK2c with according dynamic advantages. Furthermore, however is provided for an optimal clearance volume displacement by a compression-inactive arrangement of the outlet valve AV at the working-chamber-sided end of an outlet coaxial duct AKOK.
Additionally, it is yet to be indicated on a valve construction according to FIG. 7, which comes especially for outlet valves into consideration. Here, a valve body K, formed as partial sphere jacket, is swivel-mounted relative to an according form-matching valve seat around the sphere center. At the same time it requests however also a longitudinal guide by means of a swivel guide SF and a centering element CE. The latter is connected with the valve body K by a tight-elastic spring lock SV, so that for the swivel guide SF comes relative light and oscillation damping material into consideration. Regarding the mentioned swivability, the internal borehole of the swivel guide is formed slightly toroid-shaped with a suitable clearance-slip-joint for the centering element ZG. Such a construction has proved itself by high stability under load and wear resistance.
Patent Application
20100119394
