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Mechanical Seal
Repairs
Gasket Cutting
Die Formed Packing
Die Formed Grafoil
Spiral Wound Gaskets
Custom Stitched Tadpole
CNC Machined PTFE
Molded PTFE
Vulcanized O-Rings |
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Valve Packing Styles
Valve Packing
Valve packing requirements
differ from pump packing in that the key to success is not sealing a rotating shaft, the key is resisting extrusion. This much more important in some valves than others since not all applications deal with high pressure. The similarity is that both pump and valve packing need to seal reliably.
Valve packings will often be used in a combination set. A good example is flexible graphite packing generally needs to have carbon end rings, to act as a wiper and an anti-extrusion device. We offer both high end and general service carbon packings (649), since not all applications require the better but more expensive pitch based carbon yarns (698).
In 2006, the American Petroleum Institute developed API 622 as a standard for testing packing and valves for effective sealing. AS&P offers API 622 packings. To aid in the comparitaive analysis of the packings the API revised 622 to be a test of packing only. The issuance of API 622 Revision 2 in 2011 was quickly followed by the development of API 624 Valve Type Testing with Graphite Packing.
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Valve packings are selected using the following permitters
:
Temperature
PH of the media being sealed
System Pressure
While size, type of motion, condition of the valve, application, pressure excursions, existing packing, and the type of valve also must be considered the first 3 on the list will narrow the choices significantly.
If you want your Valve packing to last the longest you will use quality materials. PTFE and Flexible Graphite hold up extremely well to Chemicals. Flexible Graphite Valve packings hold up best to heat. If your application has high pressure, wire inserted packing such as 627, 677, should be considered. Anti-extrusion rings of carbon packing are also a great idea.
For help just call us at 714-593-9780
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Valve Packing Sets For Gate, Globe, Plug, needle, actuated, pressure relief, back pressure, steam and other packed valves.
The API recently released the 624 standard. It requires the use of API 622-tested packing. The API 624 specification requires the valve be tested for 310 mechanical cycles with three thermal cycles from ambient temperature to 500°F (260°C) with leakage not to exceed 100 parts per million (ppm) at any point. No packing re-torque is allowed for the duration of the test. Now that API 624 has been published, other API standards have added the requirement of passing 624 to the valve standard. For example, 624 must be passed for a valve to be labeled an API 600 valve.
In critical applications it is often a good idea to live load your valves.Details on live loading can be found here.
API continues to develop standards for testing valves and packing for low-emissions requirements and is currently working to develop API 641 for testing quarter-turn valves for compliance. |
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Application
Data
Sheet
Ameri-lon
690
Ameri-Tef
620
PTFE
Stem Packing
Ameri-Graph
696
Inconel &
Flex Graphite
677
Carbon
Packing
698
Carbon
PTFE
649
Graphited
NA
616
Valve
Packing
627
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