FSRUG Meeting, January 25-28, 2016

San Antonio, TX

Heater Drain Pump Issues

Presented by:

Mark Barber, Rotating Equipment Repair

Chris Packard, DC Cook

Subject Pump

Subject Pump

Ingersoll Rand 8 X 23 PH

1780 RPM

2 Stage

Subject Pump

The Coupling

Subject Pump

Pump History

Design Modification

• CE bearing housing changed in 2002 to incorporate sealed roller

bearing rather than babbitted journal bearing.

• This was done to minimize oil leakage.

Pump History

• TE bearing housing changed in 2002 to incorporate sealed roller

bearing rather than babbitted journal bearing with integral Kingsbury

thrust bearing.

• Done in effort to minimize oil leakage.

Pump Failures/Timeline

• A series of failures occurred:

• February, 2015: Planned 10-year maintenance performed.

• Rotor only sent out for refurbishment. Shaft replaced.

• Installation went well; turned freely on 3/26 at ambient temperatures.

• On 3/29, mechanical binding occurred during “hot alignment” checks.

• April 9, 2015: Pump disassembled. IB 2nd stage case ring bound to impeller ring

(“curl of metal”). Rotor sent to vendor.

• April 15, 2015: Vendor recommended opening up case ring to impeller running

clearances from 0.015-0.020 to 0.033-0.035 to alleviate binding issues.

• April 20, 2015: Pump assembled; rotated freely at ambient temperatures.

• A rub was noticed at a single point during “hot alignment” checks.

• April 27-28, 2015: Pump coupled and “bump checked” for rotation. Appeared to

rotate freely. On the night of 4/28, it was “aligned for its PMT tripped on a Low-

Low heater level transient.” The pump was reset. Subsequent effort to start

pump tripped motor on high amps with no flow/pressure observed.

• April 30, 2015: Entire pump removed and sent to Rotating Equipment Repair.

• Upon disassembly, it was noted:

• The shaft was made from AISI 4340 (low alloy steel).

• The case rings’ od’s were slightly pinched in their respective fit bores.

• The OB sleeve and nut had galled within its respective bushing.

• Impeller wear turn(s) had picked up galls to respective case rings.

• Shaft sleeve keyways were “end-milled.”

Disassembly Facts

Repair Plan Development

• Resultant repair plan was based on following facts:

• Due to rubbing evident more so on one end of pump, casing ring receiving

bores were suspected to be non-concentric in casing (not a singular rotor

centerline).

• Casing fits to respective stationary components were found to be out of

specification.

• As always, component materials were verified and some peculiarities were

found with the shaft. Shaft run-out necessitated its replacement.

• Impeller wear turn rubs necessitated their refurbishment.

• Bearing carrier was out of spec and required replacement.

• Shaft sleeves were replaced; keyways were milled for full key engagement.

Pump Upgrades

• A series of upgrades were implemented:

• New shaft was manufactured of martensitic SS rather than AISI 4340 as found.

• The following items were laser welded with 420 SS per ASTM B815 (450-560

BHN):

• Impeller wear turns

• Intermediate sleeves

• Shaft sleeve nuts

• New case rings manufactured from hardened 420 SS; running clearances

restored to 0.018-0.020”.

• Casing joint ground; fit bores machined concentric to one another.

• Gib blocks were manufactured for outboard end of pump casing.

The Smoking GunStarring (in alphabetical order):

• Coupling/Alignment

• Bearing Housing Design Changes

• Procedures

• Shaft Material

• Trust

• Actual coupling data states coupling can tolerate up to

0.115” radial misalignment. However, do not be fooled

into allowing excessive rim misalignment. To be sure,

install “Permalign” type laser alignment devices to

record operating temperatures vs. cold for use in

vertical rise. MINIMIZE HOT ALIGNMENT!!!

The Coupling

• Rotating Equipment Repair was brought on site to supervise the installation

and alignment of the pump.

• Soft foot checks were performed; shims were used to make corrections,

taking into account any thermal rise considerations.

• The inboard end of pump casing was put on existing dowel pins; inboard

end hold-down bolts were fastened.

• This resulted in bolt-bound condition of outboard end casing hold down

bolt holes.

Alignment

CE

DISCHARGE

SUCTION

TE

AS-FOUND ON-SITEJOB #: 20150186CASING HOLD-DOWN STUDS

ROTATING EQUIPMENT REPAIRW248 N5550 EXECUTIVE DRIVESUSSEX, WI 53089

BOLT-BOUNDCONDITION

Alignment

• INCLUDE ACTUAL DATA FROM CHRIS PACKARD!!!1

2

3

4

6 7 8

10

9

Drawing Pt. 1 2 3 4

Front Right 106.4 132.4 228.6 244.3

Front Left 102.2 132.4 191.2 205.4

Back Right 111.4 135 207.6 229.4

Back Left 103 114.4 175.6 249.8

AVE 106 129 201 232 167

Pump Support Leg Temperatures Drawing Pt. 6 7 8 9 10

Left 115.2 167.2 107.8 129 110

Right 114.8 155.6 106.2 126.8 110.6

Center

AVE 115 161 107 128 110

AVE (6-8) 128

OVERALL AVE 122

Motor Temperatures

Alignment

Thermal Rise Equation

ΔL = L * αL * ΔT

Pump

ΔT = 77°

ΔL = 18” * 5.6x10-6 * 77

ΔL = 0.0077”

Motor

ΔT = 32°

ΔL = 18” * 5.6x10-6 * 32

ΔL = 0.0032”

Therefore, set pump approximately 0.004” lower than motor.

• Alignments critical for proper pump and motor longevity.

• Thermal rise calculation

• The pump support is very well-ventilated; nearly centerline-mounted.

• Motor is well-ventilated.

Bearing Housing Design Changes

• Intent was to eliminate oil leaks and thus increase pump reliability.

• It is unclear whether MTBF has increased or decreased due to change from

babbitted journal bearings to ball bearings. The design change uses sealed

bearings, so there is a finite life expectancy of the bearings versus properly

designed and lubricated babbitted bearings.

Procedures

Pump

Number

Noun

Name RPM

Target Vertical Offset [Ref 7.2.1j]

Horizontal

Offset

Horizontal/ Vertical

Angularity

T 1-PP-22N

T 1-PP-22M

T 1-PP-22S

T 2-PP-22N

T 2-PP-22M

T 2-PP-22S

Heater

Drain 1780

WHEN Casing temp is <100°F,

THEN align Motor Shaft

0.005 to 0.009 high

WHEN Casing temp is

100°F to 250°F (Unit 1) OR

100°F to 200°F (Unit 2) Do Not perform alignment

WHEN Casing temp is

>250°F (Unit 1)

OR >200°F (Unit 2), THEN align

Motor Shaft 0.000 to 0.004 high

-0.001" to

0.001"

-0.002" to

0.002"

• Confusing procedure.

• Unless there is no alternative, NEVER PERFORM ANY HOT ALIGNMENTS!

Shaft

• Previous vendor made design change proposal to AISI 4340

• IR spec called for .12 chrome

• Coefficient of thermal expansions

• AISI 4340 13.6x10-6

• .12 chrome 5.6x10-6

• Practically this dictates that for a 250° ΔT

• AISI 4340

• 250 x 13.6x10-6 = 0.0034”

• .12 chrome

• 250 x 5.6x10-6 = 0.0014”

• Creates potential for impellers/sleeves becoming interference fit when that is

not intent of design. Face runout can then be accentuated putting the shaft

in a bow. Loose fits, as intended, allow for bore to face runout issues being

minimized.

Trust

• Just because a repair has been specified, best to “trust but verify.”

• Is pump casing machined as specified?

• To check in place, affix a precision bar, mounted in bronze bushings, to ends of casing.

• Align best possible to stuffing box bushing receiving bores.

• Using dial indicator, sweep each stationary component receiving bore to verify

they run concentrically with one another.

• Any run-out effectively reduces running clearances.

Bad Actor?

Who was the “bad actor?”

In order of influence on failure:

1. Alignment. Bolt bound condition of OB pump mounting feet

holes.

2. Procedure: HOT ALIGNMENTS

3. Trust. Verify that what you had specified work scope to be is

what you received. Scrutinize vendor design changes

carefully. They may be a good idea; they may not.

4. Shaft material. This relates to #3 above.

5. Bearing housing design changes.