Method for monitoring a centrifugal separator for a drum leakage

Abstract

This is a method for monitoring the drum of a centrifugal separator (1) for leakage, and its feature is characterized by the following steps: A. Providing a centrifugal separator (1) with an empty drum and providing a value for the reference volume of the drum (2); B. Measuring the inlet volume using a measuring device (19) until the reference volume of the drum (2) is reached; C. Measuring the pressure with a pressure sensor (24) during a phase output. D. Determining the pressure rise after reaching the reference volume and evaluating the temporal sequence of the pressure measurements; and E. Outputting a signal if the determined pressure rise falls outside the time interval after reaching the reference volume.

Description

[0001] The present invention relates to a method for monitoring a drum of a centrifugal separator for leakage. An example is known from WO9603214.

[0002] When operating a disc centrifuge, leak detection, especially in the area of ​​the so-called main drum seal, is advantageous.

[0003] It is advisable to check the drum interior for leaks at least regularly. This ensures the separator's process function and improves overall operational reliability.

[0004] Based on the aforementioned problem, the object of the present invention is to provide a method for monitoring a drum leakage, in particular during operation and, if necessary, quantifying the extent of the leakage.

[0005] The present invention solves the aforementioned problem by means of a method having the features of claim 1.

[0006] A method according to the invention for monitoring a drum of a centrifugal separator for leakage comprises the following steps: A. Preparing the centrifugal separator, comprising an emptied drum and providing a value for a reference volume of the drum; this can be done either during commissioning or during ongoing operation of the separator by first emptying the drum, then refilling it, and measuring the inflow volume and pressure in a product outlet of the drum. In the case of commissioning, the reference volume can be a predetermined design value specified by the manufacturer for the separator type. Step A is then followed by Step B. Measuring the inflow volume, at least until the reference volume of the drum is reached, using a measuring device;

[0007] In step B, the drum is filled. The added volume, especially the rinsing medium, is measured until the reference volume is reached. Measurement continues even after the reference volume is reached, at which point any pressure increase is also detected and evaluated.

[0008] A rinsing medium within the meaning of the present invention can be any liquid without solids, such as displacement water or a product phase.

[0009] If the pressure increase does not occur precisely when the reference volume is reached, the determined inlet volume at the time the pressure increase measurement is recorded can be determined. A new reference volume for filling the drum can then be calculated and stored from this inlet volume.

[0010] If, for example, a further pressure increase occurs until a constant overpressure is reached at the outlet with a constant inflow rate, this indicates that the drum is leak-proof. If no pressure increase is detected at the product outlet of a effluent phase upon reaching the reference volume, or if a pressure increase is detected after the reference volume has been reached, then the volume is leaking from another point in the drum. In other words, if the pressure increase is only observed later, despite the reference volume having been reached, then the drum is leaking. Measurement of pressure by a pressure sensor during phase D. Evaluation of the temporal sequence of pressure measurements after reaching the reference volume, determining a pressure increase. and A signal is output if the determined pressure increase lies outside a time interval after reaching the reference volume.

[0011] As can be seen from the above description, individual steps can take place simultaneously with the respective subsequent steps or transition directly into the subsequent steps.

[0012] Advantageous embodiments of the process are the subject of the dependent claims.

[0013] Providing the value for a reference volume of the drum, preferably during commissioning of the separator, can be done by the following steps: I. Providing a centrifugal separator with a predefined reference volume depending on its geometric dimensions; II. Filling the drum and determining the volume of liquid required to fill the drum, which corresponds to the currently available free drum volume, until a limit level is reached.

[0014] The limit level can be determined, for example, by a pressure sensor or a level switch. Such switches are well-known in process and measurement technology. These can be, for example, vibronic or capacitive switches. However, the pressure sensor is preferred because it can also be used to determine the free drum volume, among other things as a suitable reference volume, or to quantify the extent of the leakage.

[0015] The pressure sensor and / or the level switch can be located, in particular, at the outlet of the heavier liquid phase or the clarified phase of the separator.

[0016] The liquid introduced for filling the drum is preferably a rinsing medium, wherein a rinsing medium inlet of the separator for filling the drum and a product inlet of the separator lead into a common inlet pipe.

[0017] The volume required to fill the drum can be advantageously determined using a flow meter. For conductive media, such as water, a magnetic-inductive flow meter is particularly suitable.

[0018] The flow meter can be located in or at the product inlet of the separator and / or, more preferably, in or at the rinsing medium inlet.

[0019] If a signal is generated according to step E, the signal produces an output at an output unit, preferably a warning. Alternatively or additionally, an immediate action can be taken on the operation of the separator, in particular initiating emptying and / or shutting down the separator to prevent further product loss due to leakage and to protect the drum from wear.

[0020] Steps AE can be repeated at least twice, especially at regular intervals, whereby in step B filling can take place after emptying the drum.

[0021] At least the BE steps and preferably the entire procedure should be carried out with the drum rotating.

[0022] Another advantage of the method is that the measurement can be carried out online during the process without disassembly.

[0023] Further advantages, features, and details of the invention will become apparent from the following description, in which an embodiment of the invention is explained in more detail with reference to the accompanying drawings. Those skilled in the art will expediently consider the features disclosed in the drawing, the description, and the claims individually and combine them into meaningful further combinations. In particular, there are numerous possibilities for modifying and developing these features within the scope of the present invention. The drawings show: Fig. 1 a perspective view of a separator according to the invention; Fig. 2 a sectional view of the separator according to the invention for carrying out the method according to the invention; and Fig. 3 a schematic representation of the process sequence according to the invention.

[0024] The in the Fig. 1 and 2The illustrated embodiment shows a separator 1 with a rotatably mounted drum 2, which has a technical drum volume as a predetermined reference volume.

[0025] This drum volume is determined by the dimensions of the internal volume 12 of the drum 2, as well as by the components arranged within the internal volume 12, such as the dimensions and number of plates in a plate assembly 3 and their spacing. Furthermore, the size of the technical drum volume includes, among other things, the design of one or more inlet areas 4, distributor areas 5, separating plates 6, peeling chambers 7, peeling discs 8, discharge areas 9, and the like. The aforementioned list is by no means exhaustive. Depending on the design, individual components listed above may be omitted or replaced by other components without altering the overall principle described below.

[0026] The separator 1 also has a product inlet 10 and a rinsing medium inlet 11, which lead into a common inlet pipe 13, which in turn forms at least part of an inlet area 4 in the inner volume 12 of the drum 2.

[0027] Furthermore, separator 1 has a first outlet 14 for a light liquid phase, a second outlet 15 for a heavy liquid phase, and a solids outlet 16 as part of a solids discharge system. Separator 1 is clearly designed as a three-phase separator.

[0028] However, the following principle can also be applied to a two-phase separator, e.g. a clarification separator.

[0029] The in Fig. 1 and 2The separator 1 shown has a pressure sensor 23 and 24 at the first and second outlets 14 and 15 of the liquid phases, respectively. These pressure sensors 23 and 24 typically enable process monitoring during the separation of a light and a heavy phase, such as the purification of water contained in oil.

[0030] However, within the scope of the present invention, it is also possible to determine a reference volume and a leakage using the aforementioned sensors.

[0031] Furthermore, the separator 1 has a control water inlet 22, which is intended for controlling the solids discharge or emptying, e.g., by hydraulically actuated linear displacement of a piston valve as part of a solids emptying system. A water inlet 28 of the separator 1 branches into the two aforementioned water inlets 11 and 22. As already mentioned, the inlets 11 and 22 can also be connected to the separator separately. Therefore, there is no limitation to the configuration described.

[0032] The supply of the quantity of flushing medium to the first flushing medium inlet 11 is controlled by a valve arrangement 29, in Fig. 2 Specifically controlled by valve 18. This can preferably be a solenoid valve. Of course, the two valves 17 and 18 can also be combined in a multi-way valve, so that the valve arrangement 29 can also comprise only one valve.

[0033] The quantity and / or volume of flushing medium supplied through the flushing medium inlet 11 is determined by a suitable measuring device 19, preferably a flow meter. This can be arranged, in particular, in the flushing medium inlet 11.

[0034] The second process 15 for the heavy phase preferably also has a valve 20, preferably a solenoid valve.

[0035] The measured values ​​determined by the measuring device 19, as well as the measured values ​​of the pressure sensors 23 or 24, can be transmitted to a control and / or evaluation unit 21, which then controls the valves 17 and 18 for the control and flushing medium and the valve 20 for the heavy phase.

[0036] The aim of measuring the flow rate of the flushing medium and the associated valve control is to determine an adapted reference volume.

[0037] The determined reference volume can be compared with the manufacturer's specified initial reference volume or the actual free volume (e.g., calculated from the geometry or determined through testing). The free drum volume (technical drum volume) depends on the machine type (drum size, number and spacing of the plates, etc.) and is stored in the machine control system. The degree of contamination of the drum can then be determined from this comparison.

[0038] Determining a leak requires several steps, as described in Fig. 3 depicted.

[0039] The first step (101) is to provide a separator with an empty drum and closed inlet and outlet. Depending on the design, an initial value for a reference volume or a reference pressure is available for the separator when the drum is filled for the first time.

[0040] During commissioning, the drum volume can be measured for the first time. For this purpose, after reaching the nominal rotational speed, the drum is filled in step 102 until a defined pressure increase is detected at the pressure transmitter in one of the respective phases. The volume is stored in the drum as an adjusted reference volume. A flushing medium can be used for filling. The drum is filled by opening valve 18 until the gripper 8 is immersed in the water and the pressure at pressure sensor 24 increases. The required fill volume of liquid for filling the drum is then determined by the measuring device 19, preferably a flow meter, in particular a MID.

[0041] The determined drum volume can be saved as an adjusted reference value. If this newly determined reference value exceeds a limit, for example, 20% of a previously saved reference value (i.e., at 20% overfilling of the drum), a pressure increase should typically be observed at the end of one of the phases, at pressure sensor 24. Otherwise, a message indicating a drum leak will be issued.

[0042] The centrifugal separator can then be operated continuously, for example, to process a product. During continuous operation, the drum can be completely or partially emptied again after a predefined time interval in a third step (103), and the measurement can be performed again by introducing rinsing medium, analogous to step 102. The incoming volume is determined by the flow meter (19). The reference volume can be adjusted again. The pressure sensor detects a pressure increase.

[0043] Finally, in a fourth step 104, the inlet volume is compared as a reference value against the ongoing measurement with the flow sensor 19. If no pressure increase occurs after reaching the adjusted reference value of the drum volume, a message 105 regarding a leak is issued.

[0044] For example, if no pressure is displayed when filling to 20% above the reference volume, then an error should be displayed immediately.

[0045] If the pressure rises, valve 18 can be opened again after, for example, 5 minutes, and it is checked whether a pressure increase is immediately detected at pressure sensor 24. If this is not the case, a warning message "Check drum seal" can be issued.

[0046] The measurement can therefore be performed at regular intervals even during operation of the separator. This is done either by completely emptying the separator or by performing several partial emptyings. Afterwards, a pressure measurement can be started as described previously. Reference sign

[0047] 1 Separator 2 Drum 3 Plate pack 4 Inlet area 5 Distributor area 6 Separating plate 7 Gripper chamber light phase 8 Gripper chamber heavy phase 9 Discharge area 10 Product inlet 11 First rinsing medium inlet 12 Internal volume 13 Inlet pipe 14 First outlet (light phase) 15 Second outlet (heavy phase) 16 Solids outlet 17 Valve 18 Valve 19 Measuring device 20 Valve 21 Control and / or evaluation unit 22 Control water inlet 23 Pressure sensor 24 Pressure sensor 25 Diversion pipe 26 Solids collection area 27 Separator hood 28 Water inlet 29 Valve arrangement 101 First step (commissioning) 102 Second step (initial determination of a reference volume) 103 Third step (repetition during operation) 104 Fourth step (comparison & output) 105 message

Claims

1. Method for monitoring a drum of a centrifugal separator (1) for leakage, comprising by the following steps of: A providing the centrifugal separator (1) comprising an emptied drum and providing a value for a reference volume of the drum (2); B measuring, by means of a measuring device (19), an inflowing volume at least until the reference volume of the drum (2) is reached; C measuring a pressure by means of a pressure sensor (24) in the outlet of a phase. D evaluating the temporal sequence of the measured values of the pressure after the reference volume has been reached, and thus determining a pressure rise, and E outputting a signal if the determined pressure rise occurs outside of a time interval after the reference volume has been reached.

2. Method according to claim 1, characterized in that the provision of the value for a reference volume of the drum (2), preferably during commissioning of the separator, takes place in the following steps of: I. providing a centrifugal separator (1) with a predefined reference volume depending on its geometric dimensions; II. filling the drum (2) and determining the volume of liquid required to fill the drum (2), which corresponds to the currently available free drum volume of the drum (2), until a limit level is reached.

3. Method according to claim 2, characterized in that the limit level for indicating the maximum filling of the drum (2) is detected by measurement by means of one or more pressure sensors (23, 24) and / or by a limit level switch in the outlet of a phase.

4. Method according to one of the preceding claims, characterized in that the pressure sensor (23, 24) and / or the limit level switch is arranged at the outlet (15) of the heavier liquid phase of the separator (1).

5. Method according to one of the preceding claims, characterized in that the liquid introduced for filling the drum is flushing medium, wherein a flushing medium inlet (11) of the separator (1) for filling the drum (2) and a product inlet (10) of the separator (1) open into a common inlet pipe (13).

6. Method according to one of the preceding claims, characterized in that the volume required to fill the drum (2) is determined by a flow meter (19).

7. Method according to one of the preceding claims, characterized in that the flow meter (19) is arranged in or at the product inlet (10) of the separator and / or particularly preferably in or at the flushing medium inlet (11).

8. Method according to one of the preceding claims, characterized in that the signal initiates an output at an output unit, preferably a warning, and / or performs an immediate action on the operation of the separator, in particular initiates emptying and / or a shutdown of the separator.

9. Method according to one of the preceding claims, characterized in that steps A-E are repeated at least twice, wherein in step B a partial or complete filling can take place after a partial or complete emptying of the drum.

10. Method according to one of the preceding claims, characterized in that at least steps B-E, preferably the entire method, are carried out while the separator is rotating.

11. Method according to one of the preceding claims, characterized in that the extent of the leakage is determined and output by evaluating the pressure rise and the volume supplied within a time interval.

12. Method according to one of the preceding claims, characterized in that the entire method is carried out without dismantling the separator, in particular the drum.