Bridge MAP analyzers use specially designed sample needles and filters for sampling headspace gas.
Bridge Sample Needle vs Generic Hypodermic Needle:
The Bridge sample needle is a cross-drilled pencil-point needle designed to provide redundant gas input ports located away from the closed needle tip. Hypodermic needles, by contrast, have a single beveled sharp point entry at the needle tip. When used to sample headspace gas, the Bridge needle pierces the overwrap and pulls in sample gas through the two cross-drilled entry ports – providing a minimum of gas restriction while maintaining low needle volume. These ports are perpendicular to the needle surface and located ¼ inch from the needle tip – providing lowered risk of needle contamination. In the case where one of the ports contacts product or liquid, gas is drawn through the other open port – resulting in no vacuum being produced at the blocked port, and reducing the incidence of needle contamination.
Hypodermic needles are provided in a variety of sizes – with some having substantially larger entry volume, and some having substantially greater gas flow restriction. All of them have sharp bevel cut front entry – which is not only dangerous to the user (needle pricks), but offer no protection from contaminate ingestion. If the needle inadvertently contacts product or liquid, it can easily ingest contamination as it has a single – forward-facing entry port – as they are designed for piercing and liquid delivery or ingestion.
Bridge Sample Needle vs Single Side Port Sample Needles:
As described above, the Bridge sample needles have two gas ports positioned about ¼ inch from the end of a relatively short needle. Other side port needles are sometimes available of a similar design, but use only one side-port and are longer. These needles produce more gas restriction, are more prone to blockage, are not cleanable, and easier to bend. They are better than the hypodermic needles above, but still not recommended for use on Bridge products.
Consequences of using Unapproved Needles & Filters as opposed to Bridge Needles & Filters:
The use of generic needles and filters versus Bridge needles and filters can result in poor and unreliable analyzer performance – frequent returns for service, and early product failure.