RE: Valve seat / seal material

From: <N.>
Date: Tue May 07 2002 - 01:40:00 EDT

Engin,

Thank you for the elaborated information on Acetal. But, I am specifically looking at this soft seat material called 'POM'. This is an elastomer. I would like to know whether this material can withstand design temperatures from -40 deg. C to 200 deg. C. Also I would like to know whether this material is explosive decompression and methanol resistant. As I have methanol injection in some of my pipelines there are chances that it may loose its material properties.

Thanks and regards,

Durga Prasad

Halliburton KBR
Singapore Operations Centre
Engineering - Mechanical / Piping Department * : n.durga.prasad@halliburton.com
* : 0065-63294149 (Office)

-----Original Message-----
From: Engin Gulgun [mailto:egulgun@zy-tech.com] Sent: May 6, 2002 9:14 PM
To: 'PipingDesign@yahoogroups.com'
Subject: RE: [PipingDesign] Valve seat / seal material

Acetal is a semicristalline polyacetal-copolymner which is used for anti-extrusion rings, guide ring bushes, scrapers, and for precision-machined parts with thight tolerances. Acetal is one of the most important engineering thermoplastics with good physical properties, low water absorption and good chemical resistance. Acetal can be used in mineral oils, in water-based fire-resistant hydraulics fluids (HFA, HFB and HFC fluids), concentrated acids and bases will attack and destroy it.

Property
  Unit
  Value
  Standard

Density g/cm³
  1.40
  DIN 53479 Ball hardnessH 358/30 N/mm²
  135
  DIN 53456 Durometer hardness Shore D
  82
  DIN 53505 Yield stress N/mm²
  62
  DIN 53455 Elongation at yield %
  8 - 10
  DIN 53455 Elongation at break %
  40
  DIN 53455 Tensile-modulus N/mm²
  2600
  DIN 53457 Izod-Impact resistance

at + 23°C

at - 30°C
kJ/m²

kJ/m²

70

40

ISO 180 ISO 180 Water absorption, 23°C, satuation %
  0.8
  DIN 53495/L2 Coefficient of sliding µ
  0.17 bis 0.43

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Minimum service temperature °C

• 50

  ---

Maximum service temperature °C
  +100

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The mentioned data are only valid for test pieces of the corresponding ISO. DIN and ASTM standards and cannot be directly related to gaskets and joints. These values are only tested on selected samples.

Engin Gulgun

Zy-Tech Global Industries
Quality Manager / Mechanical Engineer
10600 Corporate Drive
Stafford TX 77477
Phone 281 275 4347
Fax 281 565 7942

-----Original Message-----
From: N. Durga Prasad [mailto:N.Durga.Prasad@halliburton.com] Sent: Friday, May 03, 2002 8:38 PM
To: 'PipingDesign@yahoogroups.com'
Subject: [PipingDesign] Valve seat / seal material

Can anyone give me an idea (details if possible) for 'POM' soft seat material used in ball valves? I have this material listed by a vendor from Denmark. It would be of very great help if somebody can provide me with catalogue information in this regard.

Thanks in advance.

Durga Prasad

Halliburton KBR
Singapore Operations Centre
Engineering - Mechanical / Piping Department

* : n.durga.prasad@halliburton.com
*  : 0065-63294149 (Office)
*   : 0065-67637294 (residence)
       : 9379-5007 (Hand phone)



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Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ Received on Tue May 07 01:40:00 2002