Product category:
Valves and manifolds
News Release from: Millipore | Subject: Aseptic Diaphragm Valve
Edited by the Processingtalk Editorial
Team on 03 June 2004
Reduced lifecycle costs with PTFE
diaphragm valves
Question - What is the life expectancy of the NovAseptic Aseptic Valve PTFE Diaphragm? Answer - 3 years and still counting!
NovAseptic Aseptic Diaphragm Valve customers have for years been experiencing positive results in terms of elimination of product hold-up, slashed maintenance times, reduced lifecycle costs and shortened CIP/SIP times when comparing their experiences with other "aseptic" valves currently in use throughout the Pharmaceutical, Biotechnology and food industries Many of the world's leading Pharmaceutical Drug and Food producers are currently moving over to Novaseptic when specifying aseptic valves for critical processes due to the aforementioned advantages
This article was originally published on Processingtalk on 1 Jul 2008 at 8.00am (UK)
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However, tests to prove the life expectancy of the NovAseptic single piece PTFE diaphragm have proved totally inconclusive! Because 3 years after the tests began, the diaphragms have shown no significant sign of damage that would result in a need for replacement! The design of the NovAseptic valve body and diaphragm is totally unique.
Each is machined from a single piece of material.
The NovAseptic diaphragm longevity is due to its rigidity and sanitary sealing mechanism, which minimises the wear that is usually associated with over compression and localised stresses exerted on thinner, multi-layer type membrane diaphragms.
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The initial capital cost of this single piece diaphragm has proven to be a hurdle to some customers who traditionally use valves incorporating multi-layer flat membrane seals.
One of these users, a large multi-national Pharmaceutical manufacturer, decided to move over to NovAseptic at one of their larger plants in Europe.
Their aim was to shorten routine maintenance times and lifecycle costs related to replacement of diaphragms on their existing valves that were installed on a liquid product distribution system.
Media temperatures were between ambient and 135C and pressures between 1 and 3 bar.
These valves were experiencing extreme conditions 24 hours per day, seven days per week.
Typically, during a year, they would expect failures, resulting in replacement of approximately 10% of diaphragms, and indeed all were replaced as a matter of routine after a year's operation due to evidence of wear.
Since moving over to NovAseptic, they have not experienced a single failure in 3 years of constant operation.
Again all diaphragms are inspected for wear on an annual basis.
It goes without saying that this particular company now utilise NovAseptic valves on all new critical aseptic process applications due to the reduction in maintenance costs.
Two further studies have been undertaken on behalf of NovAseptic to prove the durability of the PTFE diaphragm.
Firstly, one of the worlds leading suppliers of autoclaves and clean steam generation equipment, set out to test the NA valves' suitability for sterilisation processes as would generally be encountered within a typical Pharmaceutical production application.
For the purpose of this test, a dry goods/porous load cycle was selected as the challenge method due to the extremes of temperature, pressure and vacuum that are typically present.
A single NovAseptic aseptic Flow Through valve was assembled within a test rig to undergo conditions of 3 bar clean steam and a vacuum of 33mbar to simulate worst case sterilisation conditions.
The valve was set to cycle continuously for 37 seconds with full steam, and 37 seconds at vacuum.
This test was continued for 8 hours per day up to a total of 894 hours, equivalent to almost 44,000 actuations.
A typical porous load sterilisation cycle would incorporate a worst case maximum of 20 actuations per cycle.
On average between 2 to 4 sterilisation cycles are performed within a typical GMP application per day.
Even assuming 365 days per year productivity, the NovAseptic diaphragm underwent test cycles equivalent to between 1.5 and 3 years operation during the study.
On completion of the tests, the valve and diaphragm assembly was subjected to, and passed, a bubble point test using compressed air at 8 bar.
The inspection of the PTFE diaphragm proved that there was no sign of physical damage or wear.
This particular manufacturer has historically specified replacement of the membrane diaphragms every 6 months as part of its preventative maintenance program.
A further study was undertaken by an Italian Food Specialties company to determine the expected life of the PTFE diaphragm.
This potential customer was considering the NovAseptic valve for process pipeline shut-off, take-off and flow-through applications.
This plant produces betacaratene, antibiotics and other food ingredients from fermentation processes.
At the time of evaluation NovAseptic were unable to provide an accurate estimate of mean time between failures (MTBF) as the exact lifecycle was unavailable for this particular application.
The company in question set out to determine the MTBF by subjecting the valve and diaphragm to saturated steam at 3.8bar (150C), the valve being set to operate at between 32-34 strokes per minute, 24 hours per day.
After 12 days of continual operation, testing was ceased and the diaphragm inspected.
Again no physical sign of visible wear or damage was discovered.
As a result the customer in question installed NovAseptic valves on their new process system and continues to reap the benefits to this day.
NovAseptic revolutionary diaphragm is used across the whole range of dead-leg free aseptic process valve applications, and sizes: (1/2" to 3").
The NA Valve range includes sample valves, tank outlet valves, WFI and clean steam take off valves, shut off valves (all available with integral SIP/CIP satellite valve option) and a wide range of dead-leg free process valve manifolds which are fast replacing the industry standard block valves which have been prominent over the past few years. Request a free brochure from Millipore ...
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