US20230332611A1 - Centriugal pump - Google Patents
Centriugal pump Download PDFInfo
- Publication number
- US20230332611A1 US20230332611A1 US18/042,915 US202118042915A US2023332611A1 US 20230332611 A1 US20230332611 A1 US 20230332611A1 US 202118042915 A US202118042915 A US 202118042915A US 2023332611 A1 US2023332611 A1 US 2023332611A1
- Authority
- US
- United States
- Prior art keywords
- impeller
- axis
- eye
- pump
- seal surface
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000007789 sealing Methods 0.000 claims abstract description 23
- 239000002002 slurry Substances 0.000 claims description 16
- 230000001154 acute effect Effects 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005381 potential energy Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000003134 recirculating effect Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/08—Sealings
- F04D29/16—Sealings between pressure and suction sides
- F04D29/165—Sealings between pressure and suction sides especially adapted for liquid pumps
- F04D29/167—Sealings between pressure and suction sides especially adapted for liquid pumps of a centrifugal flow wheel
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/18—Rotors
- F04D29/22—Rotors specially for centrifugal pumps
- F04D29/2261—Rotors specially for centrifugal pumps with special measures
- F04D29/2266—Rotors specially for centrifugal pumps with special measures for sealing or thrust balance
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
- F04D29/426—Casings; Connections of working fluid for radial or helico-centrifugal pumps especially adapted for liquid pumps
- F04D29/4273—Casings; Connections of working fluid for radial or helico-centrifugal pumps especially adapted for liquid pumps suction eyes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D7/00—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts
- F04D7/02—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type
- F04D7/04—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type the fluids being viscous or non-homogenous
Definitions
- This invention relates to a centrifugal pump and more particularly to a seal between opposing surfaces of an impeller and an inlet liner of the pump.
- recirculation slurry flow takes place between a front shroud of the impeller and front secondary pump-out vanes, and an inlet of the pump.
- the recirculating slurry flow is abrasive and degrades the pump-out vanes and the inlet liner, resulting in component wear, a loss in pumping efficiency and an increase in energy consumption.
- FIG. 1 of the accompanying drawings shows in cross section a part of a typical centrifugal pump 10 in which recirculation of slurry leads to component wear.
- the pump 10 includes an impeller 12 , with vanes 14 , which is mounted on a shaft in a volute 16 of a casing 18 .
- a suction inlet 20 in use directs slurry in the direction of an axis 22 into a circular entrance area into the impeller, referred to as an eye 24 of the impeller.
- a clearance 30 (marked by xxx for ease of identification) is formed between a surface 32 of the impeller around the eye 24 and a spaced apart surface 34 of a front liner 36 .
- the clearance 30 forms a vertical or near-vertical (i.e.
- the invention is concerned with the aforementioned situation.
- the invention provides a centrifugal pump which includes a casing, a volute inside the casing, an impeller mounted on a shaft in the volute for rotation about an axis, the impeller including a centrally positioned eye and a plurality of vanes which extend radially outwardly from the eye, and a structure which supplies a medium to be pumped into the eye, and wherein the structure includes an outer seal surface which extends circumferentially and concentrically around the axis, which is parallel to and concentric with the axis and which extends, at least partly, into the eye, and the impeller includes an inner seal surface which extends circumferentially and concentrically around at least a part of the eye, and which is radially spaced from and which opposes the outer seal surface, whereby an axially extending, annular sealing clearance is formed between the outer seal surface and the inner seal surface.
- a second sealing clearance may extend outwardly from the axially extending annular sealing clearance at an acute angle relative to the axis.
- the axially extending annular sealing clearance may be substantially cylindrical i.e. with outer and inner surfaces which are spaced apart and which are parallel to each other and coaxial with the axis.
- the structure may supply the medium in an axial direction into the eye.
- sealing clearance refers to an arrangement in which a seal is formed between opposing surfaces of at least two components. Such seal does however form a gap between the opposing surfaces.
- FIG. 2 illustrates in cross section and from one side an end suction centrifugal slurry pump according to one form of the invention.
- FIG. 3 is a side view in cross section and on an enlarged scale of a front liner used in the pump of FIG. 2 (Item 80 in FIG. 2 ),
- FIGS. 4 A and 4 B depict, schematically, parts of the pump enclosed in a circle 4 in FIG. 2 , with different spacings between the parts, and
- FIG. 5 depicts performance curves of a conventional slurry pump and a slurry pump of the invention.
- the pump 50 includes a casing 52 which defines a volute 56 .
- An impeller 58 is mounted on a shaft 66 inside the volute for rotation about an axis 62 .
- the impeller 58 has a drive end 64 which is connected to the shaft 66 , which in use drives the impeller.
- the impeller 58 defines a centrally positioned impeller eye 68 , primary pump-out vanes 70 , and secondary pump-out vanes 72 on a front shroud 74 .
- An axially directed inlet structure 78 is mounted to the casing 52 .
- the structure 78 includes a tube 80 which is centred on the axis 62 .
- a radially extending flange 82 on the tube forms a front liner 84 for the pump.
- An inner surface 86 of the front liner opposes the vanes 72 .
- slurry is supplied in an axial direction through the tube 80 to a discharge outlet 88 and then into the eye 68 of the impeller.
- the discharge outlet 88 has a rounded inner surface 88 A—see FIG. 3 which shows the inlet structure 78 from one side and in cross section, on an enlarged scale.
- a section 90 of the tube 80 which protrudes to the left of the flange 82 has an outer seal surface 92 which is planar, which is parallel to the axis 62 and which extends circumferentially around the axis.
- a junction 94 between the section 90 and the flange 82 has a junction seal surface 96 between the outer seal surface 92 and the inner surface 86 of the front liner 84 which is at an acute angle 98 with respect to the axis 62 .
- the section 90 extends into the eye 68 which is enlarged, compared to a conventional, known, design, to accommodate this feature.
- the impeller 58 at the eye 68 has a circular inner seal surface 100 which is centered on the axis 62 and which is concentric (maybe rather use coaxial—meaning same axis) with the outer seal surface 92 .
- the inner seal surface 100 which is centred on the axis 62 and which is concentric with the outer seal surface 92 .
- the inner seal surface 100 opposes the outer seal surface 92 .
- An axially extending annular sealing clearance 102 is thereby formed between the inner seal surface 100 and the outer seal surface 92 of the section 90 .
- An inclined extension sealing clearance or seal gap 110 is thereby formed between the surfaces 106 and 96 .
- the recirculation gap 30 is established at an interface between the impeller 12 and the front liner 36 and extends in a radial direction.
- the axially extending annular sealing clearance 102 extends circumferentially around and is parallel to the axis 62 .
- the sealing clearance 102 is coaxial with the axis 62 .
- the axially extending annular sealing clearance 102 is followed by the extension sealing clearance 110 , between the surfaces 106 and 96 , which inhibits slurry entering through the tube 80 from readily flowing to the secondary pump-out vanes 72 on the front shroud of the impeller.
- FIG. 1 The prior art arrangement shown in FIG. 1 has a vertical labyrinth seal which extends in a radial direction relative to the pump axis.
- the sealing clearance 102 is established circumferentially around and coaxially with the axis 62 and thus provides a horizontal static labyrinth seal.
- FIG. 4 A illustrates schematically a portion of the pump 50 enclosed in a circle 4 in FIG. 2 .
- the extension sealing clearance 110 has a cross sectional dimension of X in the axial direction.
- the axial dimension of the extension sealing clearance 110 is increased to 3 ⁇ .
- the thickness of the annular sealing clearance 102 in a radial direction is the same. It has been established that the pump performance is largely unaffected as the size of the extension sealing clearance 110 varies. Also similar wear patterns are maintained.
- FIG. 5 shows performance curves of head in meters, and efficiency, versus flow rate (litres per second) of two pumps under test.
- the solid lines show the performance curves of a conventional pump.
- the dots indicate the performance curves of a pump according to the invention.
- An improved head is obtained with a pump according to the invention.
- the efficiency of a pump according to the invention is increased relative to the efficiency of a conventional pump.
- the invention offers an improvement of wear life of from 10% to 50% of the impeller and of the front liner of a centrifugal pump.
- the hydraulic performance of the pump is increased.
- the operation of the pump is not sensitive to the size of the axial front gap either as established during assembly or as may occur during usage. There is an overall improvement of wear life and a reduction in energy consumption.
Abstract
A centrifugal pump which includes a tubular structure which extends into an eye of an impeller and which directs a medium to be pumped into the eye, and wherein an axially extending annular cylindrical sealing clearance is formed between opposing surfaces of the impeller and the structure.
Description
- This invention relates to a centrifugal pump and more particularly to a seal between opposing surfaces of an impeller and an inlet liner of the pump.
- In a centrifugal pump, apart from a primary slurry flow, recirculation slurry flow takes place between a front shroud of the impeller and front secondary pump-out vanes, and an inlet of the pump. The recirculating slurry flow is abrasive and degrades the pump-out vanes and the inlet liner, resulting in component wear, a loss in pumping efficiency and an increase in energy consumption.
- The situation is illustrated in
FIG. 1 of the accompanying drawings which shows in cross section a part of a typicalcentrifugal pump 10 in which recirculation of slurry leads to component wear. - The
pump 10 includes animpeller 12, withvanes 14, which is mounted on a shaft in avolute 16 of acasing 18. Asuction inlet 20 in use directs slurry in the direction of anaxis 22 into a circular entrance area into the impeller, referred to as aneye 24 of the impeller. A clearance 30 (marked by xxx for ease of identification) is formed between asurface 32 of the impeller around theeye 24 and a spacedapart surface 34 of afront liner 36. Theclearance 30 forms a vertical or near-vertical (i.e. at about 90 degrees relative to the axis 22) so-called “labyrinth sealing arrangement” particularly on the radial innermost portion thereof, through which the slurry is recirculated. Theopposing surfaces front liner 36 relative to theimpeller 12, in an axial direction, is required. This type of adjustment can be difficult to achieve. - The invention is concerned with the aforementioned situation.
- The invention provides a centrifugal pump which includes a casing, a volute inside the casing, an impeller mounted on a shaft in the volute for rotation about an axis, the impeller including a centrally positioned eye and a plurality of vanes which extend radially outwardly from the eye, and a structure which supplies a medium to be pumped into the eye, and wherein the structure includes an outer seal surface which extends circumferentially and concentrically around the axis, which is parallel to and concentric with the axis and which extends, at least partly, into the eye, and the impeller includes an inner seal surface which extends circumferentially and concentrically around at least a part of the eye, and which is radially spaced from and which opposes the outer seal surface, whereby an axially extending, annular sealing clearance is formed between the outer seal surface and the inner seal surface.
- A second sealing clearance may extend outwardly from the axially extending annular sealing clearance at an acute angle relative to the axis.
- The axially extending annular sealing clearance may be substantially cylindrical i.e. with outer and inner surfaces which are spaced apart and which are parallel to each other and coaxial with the axis.
- The structure may supply the medium in an axial direction into the eye.
- As used herein “sealing clearance” refers to an arrangement in which a seal is formed between opposing surfaces of at least two components. Such seal does however form a gap between the opposing surfaces.
- The invention is further described by way of example with reference to the accompanying drawings in which:
-
FIG. 2 illustrates in cross section and from one side an end suction centrifugal slurry pump according to one form of the invention. -
FIG. 3 is a side view in cross section and on an enlarged scale of a front liner used in the pump ofFIG. 2 (Item 80 inFIG. 2 ), -
FIGS. 4A and 4B depict, schematically, parts of the pump enclosed in acircle 4 inFIG. 2 , with different spacings between the parts, and -
FIG. 5 depicts performance curves of a conventional slurry pump and a slurry pump of the invention. -
FIG. 2 of the accompanying drawings illustrates from one side and in cross section a part of an endsuction slurry pump 50 according to the invention. - The
pump 50 includes acasing 52 which defines avolute 56. Animpeller 58 is mounted on ashaft 66 inside the volute for rotation about anaxis 62. Theimpeller 58 has adrive end 64 which is connected to theshaft 66, which in use drives the impeller. - The
impeller 58 defines a centrally positionedimpeller eye 68, primary pump-outvanes 70, and secondary pump-outvanes 72 on afront shroud 74. - An axially directed
inlet structure 78 is mounted to thecasing 52. Thestructure 78 includes atube 80 which is centred on theaxis 62. A radially extendingflange 82 on the tube forms afront liner 84 for the pump. Aninner surface 86 of the front liner opposes thevanes 72. - In use slurry is supplied in an axial direction through the
tube 80 to adischarge outlet 88 and then into theeye 68 of the impeller. Thedischarge outlet 88 has a roundedinner surface 88A—seeFIG. 3 which shows theinlet structure 78 from one side and in cross section, on an enlarged scale. - A
section 90 of thetube 80 which protrudes to the left of theflange 82 has anouter seal surface 92 which is planar, which is parallel to theaxis 62 and which extends circumferentially around the axis. - In this embodiment a
junction 94 between thesection 90 and theflange 82 has ajunction seal surface 96 between theouter seal surface 92 and theinner surface 86 of thefront liner 84 which is at anacute angle 98 with respect to theaxis 62. - The
section 90 extends into theeye 68 which is enlarged, compared to a conventional, known, design, to accommodate this feature. Theimpeller 58 at theeye 68 has a circularinner seal surface 100 which is centered on theaxis 62 and which is concentric (maybe rather use coaxial—meaning same axis) with theouter seal surface 92. Theinner seal surface 100 which is centred on theaxis 62 and which is concentric with theouter seal surface 92. Theinner seal surface 100 opposes theouter seal surface 92. An axially extendingannular sealing clearance 102 is thereby formed between theinner seal surface 100 and theouter seal surface 92 of thesection 90. - A
sloping surface 106 which is adjacent theinner seal surface 100 and which is spaced from and parallel to thejunction seal surface 96 extends at theacute angle 98, relative to theaxis 62, to the secondary pump-outvanes 72. An inclined extension sealing clearance orseal gap 110 is thereby formed between thesurfaces - In the
FIG. 1 construction therecirculation gap 30 is established at an interface between theimpeller 12 and thefront liner 36 and extends in a radial direction. In theFIG. 2 case the axially extendingannular sealing clearance 102 extends circumferentially around and is parallel to theaxis 62. Thus thesealing clearance 102 is coaxial with theaxis 62. The axially extendingannular sealing clearance 102 is followed by theextension sealing clearance 110, between thesurfaces tube 80 from readily flowing to the secondary pump-outvanes 72 on the front shroud of the impeller. - The prior art arrangement shown in
FIG. 1 has a vertical labyrinth seal which extends in a radial direction relative to the pump axis. In contrast thesealing clearance 102 is established circumferentially around and coaxially with theaxis 62 and thus provides a horizontal static labyrinth seal. - In the pump 50 (
FIG. 2 ) adjustment of thefront liner 84 in an axial sense relative to theimpeller 58 is not called for. Thepump 50 is less sensitive to dimensional changes in the axial width of theextension sealing clearance 110. Wear effects at theimpeller 58 and on thefront liner 84 are significantly reduced due to the axially insensitive arrangement. The flow across the impeller vane passage, (opposing the vanes 72) during flow recirculation, is smoother as the pump is operated across its intended performance range. -
FIG. 4A illustrates schematically a portion of thepump 50 enclosed in acircle 4 inFIG. 2 . Theextension sealing clearance 110 has a cross sectional dimension of X in the axial direction. InFIG. 4B the axial dimension of theextension sealing clearance 110 is increased to 3×. However in each case the thickness of theannular sealing clearance 102 in a radial direction is the same. It has been established that the pump performance is largely unaffected as the size of theextension sealing clearance 110 varies. Also similar wear patterns are maintained. -
FIG. 5 shows performance curves of head in meters, and efficiency, versus flow rate (litres per second) of two pumps under test. The solid lines show the performance curves of a conventional pump. The dots indicate the performance curves of a pump according to the invention. An improved head is obtained with a pump according to the invention. Also the efficiency of a pump according to the invention is increased relative to the efficiency of a conventional pump. These benefits arose due to a redesign of the impeller primary pump-out vanes which was necessary due to the increase in the size of the impeller eye. The increased efficiency is demonstrated at higher flow rates. This is also the case with the head increase. These factors translate into better overall wear and potential energy savings. - The invention offers an improvement of wear life of from 10% to 50% of the impeller and of the front liner of a centrifugal pump. The hydraulic performance of the pump is increased. The operation of the pump is not sensitive to the size of the axial front gap either as established during assembly or as may occur during usage. There is an overall improvement of wear life and a reduction in energy consumption.
- It is possible to implement the principles of the invention in a retrofit manner i.e. to install an impeller and suction inlet structure which embody the described concepts, in a conventional pump.
Claims (3)
1-4. (canceled)
5. A centrifugal slurry pump (50) which includes a casing (52) which defines a volute (56) inside the casing (52), an impeller (58) mounted on a shaft (66) in the volute (56), for rotation about an axis (62), the impeller (58) including a centrally positioned eye (68), a front shroud (74) and a plurality of vanes (70,72) on the front shroud (74) which extend radially outwardly from the eye (68), and a structure (78) which is mounted to the casing (52) and which is configured to supply a medium to be pumped into the eye (68), characterized in that the structure (78) includes a tube (80) which is centered on the axis (62), a radially extending flange (82) on the tube (80) which forms a front liner (84) and which has an inner surface (86) which opposes the vanes (72) on the front shroud (74) and wherein a section (90) of the tube (80) which protrudes from the flange (82) has an outer seal surface (92) which extends circumferentially around the axis (62), which is parallel to the axis and which extends, at least partly, into the eye (68), and the impeller (58) includes an inner seal surface (100) which extends circumferentially around at least a part of the eye (68), and which is radially spaced from and which opposes the outer seal surface (92), whereby an axially extending annular sealing clearance (102) which is formed between the outer seal surface (92) and the inner seal surface (100), and a second sealing clearance (110) which extends outwardly from the axially extending annular sealing clearance (102), inhibit slurry, entering through the tube (80), from readily flowing to the vanes (72) on the front shroud (74).
6. A centrifugal slurry pump (50) according to claim 5 characterized in that the axially extending annular sealing clearance (102) is cylindrical with the outer surface (92) and the inner surface (100) which are spaced apart and which are parallel to each other and which are coaxial with the axis (62).
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ZA202005272 | 2020-08-25 | ||
ZA2020/05272 | 2020-08-25 | ||
PCT/ZA2021/050040 WO2022047507A1 (en) | 2020-08-25 | 2021-06-22 | Centrifugal pump |
Publications (1)
Publication Number | Publication Date |
---|---|
US20230332611A1 true US20230332611A1 (en) | 2023-10-19 |
Family
ID=76859837
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US18/042,915 Pending US20230332611A1 (en) | 2020-08-25 | 2021-06-22 | Centriugal pump |
Country Status (6)
Country | Link |
---|---|
US (1) | US20230332611A1 (en) |
AU (1) | AU2021334438A1 (en) |
CA (1) | CA3189702A1 (en) |
MX (1) | MX2023002173A (en) |
WO (1) | WO2022047507A1 (en) |
ZA (1) | ZA202301791B (en) |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA2015777C (en) * | 1990-04-30 | 1993-10-12 | Lynn P. Tessier | Centrifugal pump |
DE4444966A1 (en) * | 1994-12-16 | 1996-06-20 | Klein Schanzlin & Becker Ag | Pump housing |
-
2021
- 2021-06-22 MX MX2023002173A patent/MX2023002173A/en unknown
- 2021-06-22 US US18/042,915 patent/US20230332611A1/en active Pending
- 2021-06-22 WO PCT/ZA2021/050040 patent/WO2022047507A1/en active Application Filing
- 2021-06-22 CA CA3189702A patent/CA3189702A1/en active Pending
- 2021-06-22 AU AU2021334438A patent/AU2021334438A1/en active Pending
-
2023
- 2023-02-14 ZA ZA2023/01791A patent/ZA202301791B/en unknown
Also Published As
Publication number | Publication date |
---|---|
CA3189702A1 (en) | 2022-03-03 |
MX2023002173A (en) | 2023-03-16 |
AU2021334438A1 (en) | 2023-03-16 |
ZA202301791B (en) | 2023-09-27 |
WO2022047507A1 (en) | 2022-03-03 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
KR101036567B1 (en) | Improved pump impeller | |
US20220268293A1 (en) | Rotary Parts For A Slurry Pump | |
EP1284368A2 (en) | Diverter for reducing wear in a slurry pump | |
CN105134666A (en) | Anti-cavitation centrifugal pump | |
JPS58104400A (en) | Device for reducing abrasion of cavitation | |
CN108869379B (en) | Centrifugal pump sealing ring with axial guide vanes | |
US20230332611A1 (en) | Centriugal pump | |
KR101393054B1 (en) | Adapter for preventing cavitaion and centrifugal pump having adapter | |
CN111550433A (en) | Sealing ring with guide vanes in centrifugal pump | |
CA2839472C (en) | Improvements to pumps and components therefor | |
RU2808473C1 (en) | Centrifugal pump | |
US4097186A (en) | Multi-stage ring type centrifugal pumps with inducer means | |
US20160138607A1 (en) | Centrifugal pump casing with offset discharge | |
CN110005632A (en) | A kind of punching is welded into type centrifugal pump | |
US11236763B2 (en) | Inverted annular side gap arrangement for a centrifugal pump | |
WO2022266721A1 (en) | Centrifugal slurry pump impeller shroud with lip |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
AS | Assignment |
Owner name: BATTLEMAX (PTY) LTD., SOUTH AFRICA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MULLER, THOMAS;DE VILLIERS, CONRAD GRABE;BUITENDAG, MARTHINUS JACOBUS;REEL/FRAME:064577/0117 Effective date: 20230329 |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NON FINAL ACTION MAILED |