Patent Application
20230349378
The present disclosure relates to a fault-rectification method for an eccentric screw pump of a conveying apparatus for conveying viscous construction materials as per the preamble of claim 1.
WO 2019/215242 A1 has disclosed a method for operating a conveying apparatus for conveying a free-flowing construction material in which the target pressure is regulated on the basis of the detection of at least one characteristic variable. A conveying apparatus operated in this way is not capable of detecting, and/or rectifying, jamming of a rotor/stator unit of the eccentric screw pump during startup.
The present disclosure is based on an object of proposing a fault-rectification method for an eccentric screw pump of a conveying apparatus for conveying viscous construction materials by means of which operation of the eccentric screw pump is simplified.
Said object is achieved by the method sequence specified in claim 1. Advantageous and expedient refinements are specified in the dependent claims.
The fault-rectification method according to one example for an eccentric screw pump of a conveying apparatus for conveying viscous construction materials comprises the steps of:
Furthermore, it is provided that, after the end of the working-free program, the characteristic-variable-monitoring program is restarted, wherein, from the characteristic-variable-monitoring program, either the working-free program is restarted, if, for one or more characteristic variables, the characteristic-variable-monitoring program acquires characteristic-variable values which are stored, alone or in combination with one another, as fault values that indicate jamming of a rotor/stator unit of the eccentric screw pump, or otherwise the conveying operation is begun. In this way, it is ensured that the eccentric screw pump is not operated for an unnecessarily long time in the working-free program and the waiting time is thus kept as short as possible and additional loading of the eccentric screw pump is thus kept as short as possible too. In this way, it is furthermore also ensured that, by way of multiple starting of the working-free program, even relatively stubborn jamming of the eccentric screw pump can be released with acceptable loading of the eccentric screw pump.
It is also provided that, each time the drive unit is switched on in the working-free program, it is switched in each case only into forward running or in each case only into reverse running or regularly or irregularly alternatively into forward running and into reverse running. Practical tests have shown that jamming of the eccentric screw pump can generally be released by way of all four variants or else arbitrary combinations of these four variants.
Furthermore, it is provided that, prior to a restart of the working-free program, a pause time is allowed to elapse and/or a limit temperature is allowed to be reached by cooling, and that the working-free program is run through only a fixed number of times and then a complete shutdown of the conveying apparatus is carried out. In this way, the working-free program can be executed multiple times without there being a risk of overloading the eccentric screw pump, since, via the pause time and/or allowing of a limit temperature to be reached by cooling, it is ensured that the eccentric screw pump and the drive thereof, which comprises in particular a gear mechanism and a BLDC electric motor, are loaded by way of the working-free program only within permissible limits. Furthermore, a complete shutdown avoids unnecessary loading of the eccentric screw pump if the jamming cannot be rectified by a normal procedure.
It is provided that a rotational speed and/or a current consumption and/or a pressure and/or a temperature are/is detected as a characteristic variable. Monitoring of characteristic variables of said type, and in particular monitoring of multiple characteristic variables of said type, makes it possible to easily ascertain whether the eccentric screw pump is jammed or is operating in conveying operation. Characteristic variables of said type are available at modern eccentric screw pumps, or can be made available with little technical effort.
Finally, provision is made for a rotational speed and/or a current consumption and/or a pressure downstream of the rotor/stator unit and/or a temperature to be saved in a memory of the control device as a fault value. In this way, fault values saved in the control device are available for comparison with presently detected characteristic-variable values.
Jamming of an eccentric screw pump of a conveying apparatus is to be understood within the context of the present disclosure as meaning that the rotor of a rotor/stator unit through which viscous construction material is conveyed is jammed in the stator. Said jamming occurs in particular if, there, construction material has solidified and/or is clumped together and/or has become extremely viscous. “Jamming” can occur in particular if, after a pause in use of the conveying apparatus, the torque that normally prevails at the rotor of the rotor/stator unit during startup is not sufficient for turning the rotor in the stator due to lack of lubrication or due to lack of separating agent or on account of dried-on mortar residues or dried-on paint residues. In other words, “jamming” is to be understood as meaning sticking and/or adhering and/or caking-on and/or drying-on of the rotor, which is manufactured in particular from metal, in the stator, which is produced in particular from rubber.
The “jamming” is evident in particular in that the rotational speed of the rotor or the rotational speed of the electric motor is equal to zero despite very high current consumption of the electric motor. A further indicator is that the pressure in the system and in particular in the rotor/stator unit and in the hose is equal to zero upstream of the delivery apparatus, which is in the form of a gun. This is also the characteristic difference from a blockage occurring downstream of the eccentric screw pump in the hose or the gun, in the case of which the pressure is very high upstream of the blockage.
Further details of examples of the invention will be described in the drawing on the basis of schematically illustrated exemplary embodiments.
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The conveying apparatus 1 furthermore comprises a first pressure sensor 8 and a characteristic-variable-detecting device 9. In this case, a pressure at which the construction material BM is at the outlet 6 of the rotor/stator unit 5 is detected by the pressure sensor 8. The characteristic-variable-detecting device 9 comprises a rotational-speed sensor 10, by means of which a rotational speed of an electric motor 11 of the drive unit 3 of the conveying device 1 is able to be detected. In this case, the electric motor 11 is in the form of a brushless direct-current motor, a so-called BLDC electric motor 12, and the rotational-speed sensor 10 comprises at least one HALL sensor which is installed directly on the BLDC electric motor 12. Beside the drive 11, the drive unit 3 also comprises a gear mechanism 13, which is installed between the drive 11 and the eccentric screw pump 2.
A schematically illustrated temperature sensor 14 is installed on the conveying device. In this case, a temperature of a rotor 5b of the rotor/stator unit 5 is detected by the temperature sensor 14.
In
The fault-rectification method SBV comprises the steps of:
As a further step of the fault-rectification method SBV, provision may be made for:
The fault values are stored or saved in a memory of the control device.
For the working-free program FAP, it is provided that the drive unit 3, upon being switched on, is switched only into forward running or only into reverse running or regularly or irregularly alternatively into forward running and into reverse running.
In the entire programme sequence of the fault-rectification method SBV, it may be provided that, prior to each restart of the working-free program FAP, a pause time is allowed to elapse and/or a limit temperature is allowed to be reached by cooling, and that the working-free program FAP is run through only a fixed number of times and then a complete shutdown of the conveying apparatus is carried out. In this case, provision is made for monitoring of a temperature of the rotor 5b by means of the temperature sensor 14 to a limit temperature saved in the control device 4.
In the fault-rectification method SBV, use is made of a rotational speed and/or a current consumption and/or a pressure downstream of the rotor/stator unit 5 and/or a temperature as a characteristic variable for a fault value. In this case, rotational speed and current consumption are detected directly at the BLDC motor 12. In this case, pressure and temperature are detected by means of the pressure sensor 8 and the temperature sensor 14.
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 123 119.9 | Sep 2020 | DE | national |
This Application is a Section 371 National Stage Application of International Application No. PCT/EP2021/073718, filed Aug. 27, 2021, and published as WO 2022/048997A1 on Mar. 10, 2022, and claims priority to German Application No. 10 2020 123 119.9, filed Sep. 4, 2020, the contents of each are hereby incorporated by reference in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/073718 | 8/27/2021 | WO |
