EP4189244B1 - Method for operating a conveyor having an eccentric screw pump for conveying viscous construction materials - Google Patents

Description

The invention relates to an operating method for a conveying device with an eccentric screw pump for conveying viscous building materials according to the preamble of claim 1.

From the WO 2019/215242 A1 A method for operating a conveying device for conveying a flowable building material with an eccentric screw pump is known, in which the actual pressure is regulated. This operating method does not make it possible to distinguish between pressure build-up against a closed gun and conveying against an open gun. Thus, when pressure builds up against the closed gun, a so-called slip effect occurs, which leads to the building material being kneaded in the eccentric screw pump, so that the material properties of the conveyed building material are changed and the eccentric screw pump has increased wear, undesirable heating and unnecessary energy consumption.

Furthermore, the WO 2015/067582 A1 a thick matter pump is known, which comprises a conveyor screw with an inlet for thick matter to be pumped, which comprises a conveyor unit with an outlet for the thick matter to be pumped, wherein the thick matter is fed to the conveyor unit by means of a rotary movement of the conveyor screw in the conveying operation, which comprises a control device which controls the functions of the Conveying unit and the conveyor screw, and which comprises means connected to the control device which detect a disturbance in the conveying operation. When a disturbance in the conveying operation is detected, the rotary movement of the conveyor screw is switched to a reversing operation, wherein the rotational speed of the conveyor screw in the reversing operation can be set to a lower rotational speed than in the conveying operation. The corresponding method for operating a thick matter pump is also disclosed.

Finally, the DE 196 49 766 C1 A method for temperature-dependent operation of screw pumps is known in which the temperature of the pumped medium is measured in the inlet area of the pump and in the pump itself, the temperature difference between these two temperatures being determined and the pump being controlled on the basis of this determined temperature difference in comparison to a predetermined tolerance value.

It is an object of the invention to propose an operating method for a conveying device with an eccentric screw pump for conveying viscous building materials, by means of which a pressure build-up against the closed gun can be detected and, accordingly, a pressure build-up against the closed gun can be largely avoided.

This object is achieved by the features of claim 1. Advantageous and expedient further developments are specified in the subclaims.

• Erfassen eines Drucks des Baumaterials an einem Auslass der Exzenterschneckenpumpe bei laufender Exzenterschneckenpumpe und automatisches Abschalten der Exzenterschneckenpumpe, wenn der Druck einen oberen Grenzwert überschreitet;
• Erfassen einer Kenngröße der laufenden Exzenterschneckenpumpe und Vergleich der Kenngröße mit einer ersten Vergleichsgröße, welche für einen Betrieb bei geöffneter Abgabevorrichtung charakteristisch ist, und/oder mit einer zweiten Vergleichsgröße, welche für einen Betrieb bei geschlossener Abgabevorrichtung charakteristisch ist, und Abschalten der Exzenterschneckenpumpe, wenn ein Betrieb bei geschlossener Abgabevorrichtung erkannt wird;
• sofern ein Weiterbetrieb vorgenommen wird, erfolgt ein erneutes Durchlaufen der vorgenannten Schritte;
• sofern ein Abschalten der Exzenterschneckenpumpe vorgenommen wird, wird ein an dem Auslass der Exzenterschneckenpumpe vorherrschender Druck derart überwacht, dass der Betrieb der Exzenterschneckenpumpe erneut gestartet wird und die vorgenannten Schritte erneut durchlaufen werden, wenn
  • o entweder der Druck durch ein Öffnen einer Abgabevorrichtung oder eine offene Abgabevorrichtung innerhalb eines ersten Zeitintervalls um eine erste Druckdifferenz abfällt
  • o oder der Druck systembedingt bei geschlossener Abgabevorrichtung langsamer auf einen unteren Grenzwert oder um eine zweite Druckdifferenz abfällt, wobei die zweite Druckdifferenz größer ist als die erste Druckdifferenz.

The operating method according to the invention for a conveying device with an eccentric screw pump for conveying viscous building materials comprises the steps:

• Detecting a pressure of the building material at an outlet of the Eccentric screw pump when the eccentric screw pump is running and the eccentric screw pump is automatically switched off when the pressure exceeds an upper limit;
• Detecting a characteristic of the running eccentric screw pump and comparing the characteristic with a first comparison value which is characteristic of operation with the dispensing device open and/or with a second comparison value which is characteristic of operation with the dispensing device closed, and switching off the eccentric screw pump if operation with the dispensing device closed is detected;
• If continued operation is carried out, the above steps will be repeated;
• if the eccentric screw pump is switched off, the pressure prevailing at the outlet of the eccentric screw pump is monitored in such a way that the operation of the eccentric screw pump is restarted and the above steps are repeated if
  • o either the pressure drops by a first pressure difference due to an opening of a dispensing device or an open dispensing device within a first time interval
  • o or the pressure drops more slowly to a lower limit value or by a second pressure difference when the dispensing device is closed, whereby the second pressure difference is greater than the first pressure difference.

This prevents the building material in the eccentric screw pump from being unnecessarily milled when the gun is closed. This avoids a change in the material properties of the pumped building material caused by milling and prevents both increased wear and unnecessary energy consumption. as well as avoiding unwanted heating.

It is also intended that a pulsation pattern occurring in the eccentric screw pump during conveying operation is continuously recorded as a characteristic value and that this is continuously compared with a first pulsation pattern stored as the first comparison value and/or with a second pulsation pattern stored as the second comparison value. By comparing the stored pulsation patterns, it can be reliably determined whether the eccentric screw pump is building up pressure against a closed gun or is conveying against an open gun.

It is also intended that a temperature of the eccentric screw pump and in particular a temperature of a rotor of a rotor-stator unit of the eccentric screw pump is continuously recorded as a parameter and that this is continuously compared with the temperature stored as the first comparison value and/or with the temperature stored as the second comparison value. This makes it easy to see that the eccentric screw pump is building up pressure against a closed gun and working through the building material, as this leads to heat development and thus also quickly leads to an increase in the temperature of the eccentric screw and thus also of the rotor of the eccentric leg.

Furthermore, it is provided that the first and/or second pulsation pattern stored as a comparison value is created on the basis of pressure values recorded with the pressure sensor and/or on the basis of speed values of a BLDC electric motor driving the eccentric screw pump and/or on the basis of current values of a BLDC electric motor driving the eccentric screw pump that are typical for an applied torque. In this way, the pulsation pattern can be created with the Conveyor device installed technology can be easily determined.

Finally, it is intended that after the eccentric screw pump has been temporarily switched off, it will be switched off permanently if the pressure drops by a third pressure difference within a third time interval, whereby the third time interval and the third pressure difference are typical for a rotor-stator unit that is defective due to wear. This makes it easy to recognize and signal that the eccentric screw pump has reached a wear limit and should be replaced. This means that the user can also be informed visually and/or acoustically that the wear limit has been reached.

Further details of the invention are described in the drawing using schematically illustrated embodiments.

In the sense of the invention, switching off the eccentric screw pump means automatically switching off the BLDC electric motor, which drives the eccentric screw pump via a gear unit.

For the purposes of the invention, a pressure prevailing at an outlet of the eccentric screw pump is understood to mean a pressure which is detected in a conveying section following the eccentric screw pump.

In the sense of the invention, a first comparison value and a second comparison value are understood to mean a data set describing the first or second stored pulsation pattern or a formula describing the first or second stored pulsation pattern. The respective data set or the respective formula describes a Pulsation pattern which is determined on the basis of pressure values recorded with a pressure sensor and/or which is determined on the basis of speed values of a BLDC electric motor driving the eccentric screw pump and/or which is determined on the basis of current values of a BLDC electric motor driving the eccentric screw pump which are typical in particular for an applied torque.

Likewise, a detected parameter within the meaning of the invention is also understood to mean a data set describing a detected pulsation pattern or a formula describing the detected pulsation pattern.

Figur 1:

eine perspektivische Ansicht einer Fördervorrichtung,

Figur 2:

eine geschnittene Seitenansicht der in der Figur 1 gezeigten Fördervorrichtung und

Figur 3:

ein schematisches Ablaufdiagramm eines Betriebsverfahrens.

This shows:

Figure 1:

a perspective view of a conveyor device,

Figure 2:

a cut side view of the Figure 1 shown conveyor device and

Figure 3:

a schematic flow diagram of an operating procedure.

In the Figure 1 a conveying device 1 for carrying out the method according to the invention is shown in perspective view.

In the Figure 2 is the one from the Figure 1 known conveying device 1 is shown in a partially sectioned side view. The conveying device 1 comprises an eccentric screw pump 2, a drive unit 3 and a control device 4. The eccentric screw pump 2 comprises a rotor-stator unit 5 with an upstream conveyor screw 5a and an outlet 6. Furthermore, the conveying device 1 comprises a schematically shown conveying section 7, which is connected to the outlet 6 of the rotor-stator unit 5. The conveying section 7 comprises a hose 7a and a dispensing device 7b, by means of which the discharge of viscous building material BM can be activated and deactivated and preferably also dosed.

The conveying device 1 also comprises a first pressure sensor 8 and a characteristic detection device 9. The pressure sensor 8 detects a pressure under which the building material BM is at the outlet 6 of the rotor-stator unit 5. The characteristic detection device 9 comprises a speed sensor 10, by means of which a speed of an electric motor 11 of the drive unit 3 of the conveying device 1 can be detected. The electric motor 11 is designed as a brushless direct current motor, so-called BLDC electric motor 12, and the speed sensor 10 comprises, according to one embodiment variant, at least one HALL sensor installed directly on the BLDC electric motor 12. The drive unit 3 comprises not only the drive 11 but also a gear 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. The temperature sensor 14 detects a temperature of a rotor 5b of the rotor-stator unit 5.

In the Figure 3 A simplified flow chart of an operating procedure BV is shown.

• Im Rahmen eines Drucküberwachungsprogramms DUP erfolgt ein Erfassen eines Drucks des zähflüssigen Baumaterials an einem Auslass der Exzenterschneckenpumpe bei laufender Exzenterschneckenpumpe und automatisches Abschalten der Exzenterschneckenpumpe, wenn der Druck einen in der Kontrolleinrichtung gespeicherten oberen Grenzwert überschreitet;
• Im Rahmen eines Kenngrößenüberwachungsprogramms KUP erfolgt ein Erfassen einer Kenngröße der laufenden Exzenterschneckenpumpe und Vergleich der Kenngröße mit einer ersten in der Kontrolleinrichtung gespeicherten Vergleichsgröße, welche für einen Betrieb bei einer geöffneten Abgabevorrichtung charakteristisch ist, und/oder Vergleich der Kenngröße mit einer zweiten in der Kontrolleinrichtung gespeicherten Vergleichsgröße, welche für einen Betrieb bei geschlossener Abgabevorrichtung charakteristisch ist, und Abschalten der Exzenterschneckenpumpe, wenn ein Betrieb bei geschlossener Abgabevorrichtung erkannt wird;
• sofern ein Weiterbetrieb der Exzenterschneckenpumpe vorgenommen wird, erfolgt ein erneutes Durchlaufen der vorgenannten Schritte und hiermit des Drucküberwachungsprogramms DUP und des Kenngrößenüberwachungsprogramms KUP;
• sofern durch die vorgenannten Schritte ein Abschalten der Exzenterschneckenpumpe vorgenommen wird, wird ein an dem Auslass der Exzenterschneckenpumpe vorherrschender Druck mit einem Abgabeüberwachungsprogramm AUP und einem Niederdrucküberwachungsprogramm NUP derart überwacht, dass der Betrieb der Exzenterschneckenpumpe erneut gestartet wird und die vorgenannten Schritte erneut durchlaufen werden, wenn
  • o entweder durch das Abgabeüberwachungsprogramm AUP festgestellt wird, dass der Druck durch ein Öffnen einer Abgabevorrichtung oder eine offene Abgabevorrichtung innerhalb eines ersten Zeitintervalls um eine vorgegebene Druckdifferenz abfällt, wobei z.B. ein Abfall des Drucks um 10 bar in 1 bis 2 Sekunden detektiert sein muss
  • o oder durch das Niederdrucküberwachungsprogramm NUP festgestellt wird, dass der Druck systembedingt bei geschlossener Abgabevorrichtung langsamer auf einen unteren Grenzwert oder um eine zweite Druckdifferenz abfällt, wobei der Druck z.B. in 30 Minuten um 50 bar unter einen Sollwert abfällt und wobei die zweite Druckdifferenz größer ist als die erste Druckdifferenz,
• wobei die Exzenterschneckenpumpe anderenfalls abgeschaltet bleibt und eine Drucküberwachung fortgesetzt wird.

The BV operating procedure includes the following steps:

• As part of a pressure monitoring program DUP, a pressure of the viscous building material is recorded at a Discharge of the eccentric screw pump when the eccentric screw pump is running and automatic shutdown of the eccentric screw pump when the pressure exceeds an upper limit stored in the control device;
• As part of a characteristic monitoring program KUP, a characteristic of the running eccentric screw pump is recorded and the characteristic is compared with a first comparison value stored in the control device, which is characteristic of operation with an open dispensing device, and/or the characteristic is compared with a second comparison value stored in the control device, which is characteristic of operation with a closed dispensing device, and the eccentric screw pump is switched off if operation with a closed dispensing device is detected;
• If the eccentric screw pump is to be operated further, the aforementioned steps are repeated, including the pressure monitoring program DUP and the parameter monitoring program KUP;
• if the eccentric screw pump is switched off by the aforementioned steps, a pressure prevailing at the outlet of the eccentric screw pump is monitored with a discharge monitoring program AUP and a low pressure monitoring program NUP in such a way that the operation of the eccentric screw pump is restarted and the aforementioned steps are repeated if
  • o either the dispensing monitoring program AUP determines that the pressure has dropped by a predetermined amount due to an opening of a dispensing device or an open dispensing device within a first time interval Pressure difference drops, whereby e.g. a drop in pressure of 10 bar must be detected in 1 to 2 seconds
  • o or the low pressure monitoring program NUP determines that the pressure drops more slowly to a lower limit value or by a second pressure difference when the dispensing device is closed, whereby the pressure drops by 50 bar below a setpoint value in 30 minutes, for example, and whereby the second pressure difference is greater than the first pressure difference,
• Otherwise the eccentric screw pump remains switched off and pressure monitoring continues.

It is optional - as in the Figure 3 shown schematically with dashed lines - provided that the operating method is supplemented by a wear monitoring program VUP such that after an interim shutdown of the eccentric screw pump 2, a final shutdown takes place if the pressure drops by a third pressure difference within a third time interval, wherein the third time interval and the third pressure difference are selected depending on the conveying device 1 such that they are typical for a rotor-stator unit 5 defective due to wear.

The conveying device 1 can further be operated in such a way that the control device 5 continuously records a pulsation pattern occurring in the eccentric screw pump 2 as a characteristic variable and this is continuously compared by the control device 5 with a first pulsation pattern stored as a first comparison variable in the control device 5 and/or with a second pulsation pattern stored as a second comparison variable in the control device.

Alternatively, the conveyor can also be operated in such a way that the control device 5 continuously outputs a Temperature of the eccentric screw pump 2 and in particular a temperature of a rotor 5b of a rotor-stator unit 5 of the eccentric screw pump 2 is recorded and this is continuously compared with the temperature stored as the first comparison variable in the control device 5 and/or with the temperature stored as the second comparison variable in the control device 5.

It is provided that, as a comparison value, a first and a second stored pulsation pattern are created on the basis of pressure values recorded with the pressure sensor 8 and/or on the basis of speed values of a BLDC electric motor 12 driving the eccentric screw pump 2 and/or on the basis of current values of a BLDC electric motor 12 driving the eccentric screw pump 2.

List of reference symbols:

1

Conveyor device

2

Eccentric screw pump

3

Drive unit

4

Control device

5

Rotor-stator unit

5a

Conveyor screw of 5

5b

Rotor of 5

6

Outlet

7

Conveyor section

7a

Hose of 7

7b

Dispensing device of 7

8th

Pressure sensor

9

Parameter recording device

10

Speed sensor

11

Electric motor

12

BLDC electric motor

13

transmission

14

Temperature sensor

BM

viscous building material

BV

Operating procedures

DUP

Pressure monitoring program

KUP

Parameter monitoring program

AUP

Delivery monitoring program

NUP

Low pressure monitoring program

VUP

Wear monitoring program

Claims (5)

1. Operating method (BV) for a conveying device (1) with an eccentric screw pump (2) for conveying viscous construction materials (BM) comprising the following steps:

   - sensing a pressure of the construction material (BM) at an outlet (6) of the eccentric screw pump (2) when the eccentric screw pump (2) is running and automatically switching off the eccentric screw pump (2) if the pressure exceeds an upper limit value, otherwise continued operation of the eccentric screw pump (2) ;

   - sensing a characteristic variable of the running eccentric screw pump (2) and comparison of the characteristic variable (2) with a first comparison variable, which is characteristic of operation with an open dispensing device (7b), and/or with a second comparison variable, which is characteristic of operation with a closed dispensing device (7b), and switching off the eccentric screw pump (2) if operation with a closed dispensing device (7b) is detected, otherwise continued operation of the eccentric screw pump (2);

   - if continued operation is undertaken, renewed performance of the aforementioned steps takes place;

   - if switching off of the eccentric screw pump (2) is undertaken, a pressure prevailing at the outlet (6) of the eccentric screw pump (2) is monitored in such a way that the operation of the eccentric screw pump (2) is started once again and the aforementioned steps are performed once again if

   o either the pressure falls by a first pressure difference within a first time interval due to opening of a dispensing device (7b) or an open dispensing device (7b)

   o or, for system-related reasons, the pressure falls more slowly to a lower limit value or by a second pressure difference with a closed dispensing device (7b), the second pressure difference being greater than the first pressure difference.
2. Operating method according to Claim 1, characterized in that a pulsation pattern occurring in the eccentric screw pump (2) during the conveying operation is continuously sensed as a characteristic variable and is continuously compared with a first pulsation pattern, stored as a first comparison variable, and/or with a second pulsation pattern, stored as a second comparison variable.
3. Operating method according to Claim 1, characterized in that a temperature of the eccentric screw pump (2), and in particular a temperature of a rotor (5b) of a rotor-stator unit (5) of the eccentric screw pump (2), is continuously sensed as a characteristic variable and is continuously compared with the temperature stored as a first comparison variable and/or with the temperature stored as a second comparison variable.
4. Operating method according to Claim 2, characterized in that the first and/or second pulsation pattern stored as a comparison variable

   - is created on the basis of pressure values sensed by the pressure sensor (8)

   - and/or is created on the basis of speed values of a BLDC electric motor (12) driving the eccentric screw pump (2)

   - and/or is created on the basis of current intensity values of a BLDC electric motor (12) driving the eccentric screw pump (2).
5. Operating method according to Claim 1, characterized in that, after an interim switching off of the eccentric screw pump (2), a final switching off takes place if the pressure falls by a third pressure difference within a third time interval, the third time interval and the third pressure difference being typical of a rotor-stator unit (5) that is defective due to wear.

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