Page 122 - GarlockFluidSealing2010

D-4

Performance Metrics

Controlled Density

™

Process

¦

Garlock manufacturing process ensures optimum

fller density across the gasket winding to achieve

consistent compression and superior sealability

¦

High tightness level achieved with minimal com-

pressive load, for longer-lasting seal

¦

All SW gaskets manufactured in accordance with

the guidelines set forth in the ASME B16.20 specif-

cations

ROTT Test and Results

ROTT Test

¦

Purpose:

Determine room temperature sealing ca-

pabilities, by measuring the sealability of a gasket

at incremental gasket stress values

¦

Sample used:

Two 304 SS and fexible graphite-

flled 4" Class 150 ASME B16.20 spiral wound

gaskets

¦

Procedure:

The leak rate is measured during the

loading and unloading cycles, and a tightness

curve is generated.*

Gasket

Stress Req'd

Stress Req'd Stress Req'd

Gasket Material

Constant Constant Constant

for Tightness

for Tightness for Tightness

Gb (psi)

'a'

Gs (psi)

of 100 (psi)

of 1000 (psi) of 10,000 (psi)

Garlock fexible graphite-flled

spiral wound gasket (ASME

627

0.35

6.22

3,140

7,040

11,430

B16.20)

Flexible graphite spiral wound

2,300

0.237

13

6,851

11,823

20,405

gasket

PTFE-flled spiral wound gasket

4,500

0.14

70

8,575

11,836

16,339

Foil-reinforced fexible graphite sheet

816

0.377

0.066

4,631

11,033

26,284

Garlock GRAPHONIC

®

gasket

315

0.36

1.857

1,653

3,787

8,676

"Low stress" spiral wound type

gasket, fexible graphite flled

598

0.385

0.03

3,520

8,540

14,570

Garlock Kammprofle gasket

368

0.4

0.28

2,324

5,838

14,664

Test Results

¦

When compared with other spiral wound gaskets,

the Garlock metallic gasket was able to achieve

equivalent tightness at a lower load in all tightness

parameter values.

¦

During stress cycling, the performance of the

Garlock metallic gasket gaskets was excellent,

compared with other spiral wound gaskets.

Comparison of Seating Requirements

Note: For a 5" OD gasket at 800 psig, Tp100 = 102ml

/ min. leakage,

Tp1,000 = 1.02ml

/ min. leakage, Tp10,000 = 0.01 ml

/ min. leakage.

* Gb = stress at which seal is initiated; "a" = the slope of the log/log tightness

curve; Gs = intersection of the unload curve with the vertical axis (Tp1)

Gasket

Gasket Style and Material

Factor

"M"

"Y" (psi)

Traditional spiral wound gasket—

3.00

10,000

304 SS and fexible graphite

Garlock spiral wound gasket

3.00

7,500