Case Study - Oil Well Water Injection Microfilter Sight Glasses

The Product/Service
High pressure sight glass for use on off shore oil well water injection membrane filter assemblies.
Global provider of upstream water treatment solutions to the oil and gas industry.
End User
Off shore oil development in Angola
The Problem
Before sea or produced water can be injected into the oil well to increase pressure and support the reservoir it has to be cleaned and micro filtered to prevent scale contamination of piping and the reservoir. The nano filtration membranes used to remove sulphates are housed in pressure vessels. Early indications of filter failure are tell tale gas bubbles in the downstream processed water. High pressure rated, robust sight glasses were required to give clear indication of filter replacement. Due to the very high volumes of water involved several hundred nanofilter membranes are utilised, each one requiring a pressure vessel and sight glass combination.
The Solution
CRPs engineering team designed a FEP (Fluorinated ethylene propylene) lined sight glass. The heavy wall FEP iner was supported within a stainless steel tube with laser cut viewing holes. The steel pipe was cold form flared using the Vanstone technique to create a one piece robust construction. The FEP was flared over the flange faces ensuring that there were no metallic wetted parts. Burst pressure tests were carried out on the sight glass, eventually the sight glass failed at an incredible 160 bar g, far surpassing the customers actual requirements. The sight glasses are lined in TeflonÒ Process G fluoropolymer. This is manufactured by DuPont using a revolutionary new technology based on Super Critical CO2 as the polymerisation reaction media. This provides increased tensile strength and elongation at higher temperature and increased stress crack resistance. This is combined with better thermal and colour stability and less creep. In particular it was selected for this product because of its enhanced optical properties, both transparency and UV transmittance, whilst retaining the same chemical properties as conventional FEP. On a standard test UV transmittance was between 10 and 20% better than standard FEP.

  TeflonÒ is a registered trademark of DuPont used under licence by CRP.

Contact Details

Corrosion Resistant Products Ltd
Todmorden Road
OL15 9EG

Phone: +44(0)1706 756400
Fax: +44(0)1706 379567