# US 10,480,517 B2 · Method of and arrangement for monitoring the condition of a volute casing of a centrifugal pump

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- Number: US 10,480,517 B2
- Document ID: US10480517B2
- Status: Granted
- Kind: B2
- Application number: 15/720,893
- Filed: 2017-09-29
- Published: 2018-05-03
- Granted: 2019-11-19
- Earliest claimed: 2016-10-27
- Assignees: Sulzer Management AG
- Applicants: Sulzer Management AG
- Inventors: Kalle Tarhonen
- Web page: https://patentgrep.com/patent/US10480517B2

## CPC

- G01M 13/00: Testing of machine parts
- F04D 1/00: Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps (adapted for pumping specific fluids F04D7/00; priming or boosting F04D9/00)
- F04D 7/04: the fluids being viscous or non-homogenous
- F04D 15/0088: {Testing machines}
- F04D 15/0272: {the condition being wear or a position}
- F04D 29/428: {Discharge tongues (F04D17/04 takes precedence)}
- G01H 1/00: Measuring {characteristics of} vibrations in solids by using direct conduction to the detector (G01H9/00, G01H11/00 take precedence)
- F05B 2260/80: Diagnostics
- F05B 2270/80: Devices generating input signals, e.g. transducers, sensors, cameras or strain gauges
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- G01H: MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G

## Abstract

A method of monitoring the condition of a volute casing of a centrifugal pump, the method includes determining, in a wall of the volute casing, at least one point, which, in view of the material forming the volute casing, is critical to wear, providing, from outside the volute casing, a blind hole in the wall of the volute casing at the at least one point, the blind hole having a depth, receiving information from the blind hole, and taking predetermined actions to replace the volute casing with a new casing after the information indicates the opening of the blind hole into the interior of the volute casing.

## Claims

### Claim 1

A method of monitoring a condition of a volute casing of a centrifugal pump, the volute casing comprising an outlet duct with a wall and an outlet opening, a centreline plane, a cutwater tongue, an axis, and a wall having an inner surface defining an interior of the volute casing and an outer surface, the method comprising:
determining, in the wall of the volute casing, at least one point, which, in view of the material forming the volute casing, is critical to wear;
providing, from outside the volute casing, a blind hole in the wall of the volute casing at the at least one point, the blind hole having a depth;
receiving information regarding the blind hole; and
taking predetermined actions to replace the volute casing with a new casing after the information indicates the blind hole opens into the interior of the volute casing.

### Claim 2 (depends on 1)

The method as recited in claim 1, wherein, the determining the at least one point includes determining the at least one point for a pump made of a high-tensile steel or ductile iron to such a position in the volute casing that has, in an axial cross section of the volute casing, the longest distance from the axis, the at least one point being where the volute casing subjected to maximal abrasive load.

### Claim 3 (depends on 1)

The method as recited in claim 1, wherein, the providing the blind hole includes positioning the blind hole in the wall of the volute casing in close proximity of the cutwater tongue.

### Claim 4 (depends on 1)

The method as recited in claim 1, wherein the determining the at least one point includes determining the at least one point for a pump made of a hard and brittle cast iron, at such a position in the volute casing that a radius of the inner surface of the volute casing, in an axial cross section, is smallest, the position being where the volute casing is subjected to maximal principal stress, and the providing, from the outside the volute casing, the blind hole in the wall of the volute casing includes providing the blind hole at the at least one point.

### Claim 5 (depends on 1)

The method as recited in claim 1, wherein, the determining the at least one point includes determining the at least one point for a pump made of a hard and brittle cast iron at such a position that the cutwater tongue joins to a side wall of the volute casing, and the providing, from outside the volute casing, the blind hole in the wall of the volute casing includes providing the blind hole at the at least one point.

### Claim 6 (depends on 1)

The method as recited in claim 1, wherein, the determining the at least one point includes determining the at least one point for a pump made of a hard and brittle cast iron in the cutwater tongue at the centreline plane of the volute casing, and the providing, from outside the volute casing, the blind hole in the cutwater tongue of the volute casing includes providing the blind hole at the at least one point.

### Claim 7 (depends on 1)

The method as recited in claim 1, further comprising, determining the depth of the blind hole to correspond to a smallest safe thickness of the wall of the volute casing in relation to either strength requirements or resistance to wear of the volute casing in the point.

### Claim 8 (depends on 1)

The method as recited in claim 1, further comprising determining the depth of the blind hole to correspond to a smallest usable thickness of the wall of the volute casing in view of flow conditions at the cutwater tongue.

### Claim 9 (depends on 1)

The method as recited in claim 1, further comprising arranging a sensor in communication with the blind hole, the sensor configured to send a signal when the blind hole opens to the interior of the volute casing.

### Claim 10 (depends on 1)

The method as recited in claim 1, wherein, the receiving information includes receiving visual information regarding the blind hole or a signal from a sensor, in communication with the blind hole.

### Claim 11

An arrangement for monitoring a condition of a volute casing of a centrifugal pump, the pump having a volute casing and an axis, the volute casing comprising an outlet duct, an outlet opening, a centreline plane extending at right angles to the axis, a wall having an inner surface defining an interior of the volute casing and an outer surface, and at least one blind hole arranged to extend in a depth in the outer surface of the wall of the volute casing; the arrangement comprising:
at least one blind hole arranged in a position where the principal stress or the abrasion subjected to the volute casing is maximal.

### Claim 12 (depends on 11)

The arrangement as recited in claim 11, wherein the at least one blind hole is arranged in the volute casing in a position that has, in an axial cross section of the volute casing, a longest distance from the axis.

### Claim 13 (depends on 11)

The arrangement as recited in claim 11, wherein the depth of the at least one blind hole is arranged to correspond to a smallest usable thickness of the wall of the volute casing in view of the flow conditions at the cutwater tongue.

### Claim 14 (depends on 11)

The arrangement as recited in claim 11, wherein the at least one blind hole is arranged to a position where a radius R of curvature of the inner surface of the wall of the volute casing in an axial cross section of the volute casing is smallest.

### Claim 15 (depends on 14)

The arrangement as recited in claim 14, wherein the at least one blind hole includes several blind holes arranged on an entire circumference of the volute casing.

### Claim 16 (depends on 14)

The arrangement as recited in claim 14, further comprising a sensor in communication with the at least one blind hole.

### Claim 17 (depends on 16)

The arrangement as recited in claim 16, wherein the sensor is one of a pressure sensor and a conductivity sensor.

### Claim 18 (depends on 11)

The arrangement as recited in claim 11, wherein the at least one blind hole is arranged at the cutwater tongue at the centreline plane of the volute casing.