Accessories
Gas Sampling Bags – Valves
A choice of two valves can be ordered as standard equipment with all bags. These are either:
- Twist-type Valve with hose barb
or
-
Straight-through Connection (STC).
Standard Valves
Twist-Type (V-NPB-1-TT), Figure 1
The Twist-Type Valve (NPB) with hose barb connection can be ordered as a standard feature. Gas flow can be controlled by turning the valve which gradually opens or closes it. The jagged ridge on the hose barb secures the tubing to the stem. To allow gas to flow, the valve must be turned counter-clockwise and, similarly, clockwise to stop the flow.
Tubing should be cut 90o to its own sidewall. When attached, it should extend far enough down the barbed stem to avoid potential leakage (between the stem and base) but not so far that it prevents the stem from turning.
Straight Through Connection (STC-NPB-F-SR), Figure 2
The Straight Through Connection (STC) can be ordered as a standard feature instead of the Twist-Type valve. The Straight-Through Connection (STC) is any unobstructed gas channel connection that does not allow the user to control the flow of gas. Two STC’s may be used to allow a continuous flow of gas or liquid through the bag, if the bag is to be used as a buffer. Used in conjunction with another type of valve (inlet port), an STC may also be installed as an outlet purge-port, so as to permit a flow-through purge (cleaning) of the bag after each use. (In this case, for gas sampling, a short piece of tubing must be placed on the STC and a closing device (such as a plastic medical tubing clamp) then placed on this tubing.)
Two types of STC’s are available - either as a smooth shaft with swage-ring (shown in Figure 2) or as a tyre valve with closing stem removed (but with threaded-cap). Both are available in nickel plated brass.
The „swage-ring“ (small circle at the end of the smooth-shaft STC) facilitates the use of a „quick connect“ sample line adapter, and in particular the „Swagelok™“ line of fittings.
Of course, tyre valves can also be provided with their original closing stems installed, see ->„Optional Valves“ ->„Tyre Valves“. An optional 6" length (threaded-twist) sample line connection is also available for use with the tyre valve STC.
Optional Valves
Twist-Type Double-O-Ring (V-NPB-2/OO), Figure 3
The Twist-Type Double-O-Ring Valve operates in the same way as the Twist-Type Valve (Figure 1). However, this valve has the special added feature of a secondary O-ring installed on the valve stem, greatly reducing or eliminating gas loss at recommended inflation pressures.
Luer-Fit Valve™ (V-L/F-1), Figure 4
The Luer-Fit Valve™ is a secure, self-closing valve which cannot be opened or left open accidentally, thus preventing any loss of gas or liquid sample. It is easy to use and requires no turning or twisting of the valve stem.
The Luer-taper Quik-Mate™ Connector (shown above the Luer-Fit Valve™), standard with each Luer-Fit Valve™, is a flow-through adapter for instant (push-pull) connection of tubing to the valve. The tapered fitting between the valve stem housing and Quik-Mate™ Connector becomes tighter as pressure is exerted on the Quik-Mate. This ensures a gas-tight fit between the sample line tubing and the Luer-Fit Valve™.
Gases can be inserted or withdrawn through the use of either sample line tubing or a syringe with a Luer-taper barrel fitting. This valve can eliminate the need to work with syringe-needles, if desired. The Luer-Fit Valve™ is also compatible with our full line of sampling accessories, including the Hann-Pump™.
Please Note: Because of its tiny gas channels, the Luer-Fit Valve™ is not suitable for gases with particulate. It also has a lower flow rate than other valve connections at the same pressure. Further, one must be aware of „dead space“ which may occur when using a syringe with a needleless syringe barrel, to withdraw or inject sample gas or liquid through the valve-stem housing.
Stopcock-valve, Figure 5
from left to right, from top to bottom: STOPCK-DE/1500, STOPCK-SEP, STOPCK-ROT/L1200, STOPBASE-F)
The Stopcock-Valve is one of our most popular valves because of its many different applications. This valve allows the user to control the flow of gas with greater flexibility. It consists of two pieces - a stopcock-base and a stopcock valve assembly which connects independently to the base by means of a rotating locking nut.(Figure left to right: Closing Cap ”STOPCK-DE/1500”, Stopcock-Septum “STOPCK-SEP”, 1-way-Stopcock “STOPCK-ROT/ L1200”)
The base “STOPBASE-F” can also be used as a Straight-Through Connection (STC) simply by attaching tubing using the Quik-Mate™ Connector. The Stopcock Valve (connected to the base by a clockwise twisting motion) is also compatible with all our Luer-taper collection accessories. Tubing can also be easily fitted to the end of the Stopcock Valve using the Quik-Mate™ Connector.
An optional self-sealing Stopcock-Septum, directly connected with a clockwise twisting motion to either the stopcock base alone or to the top of the stopcock-valve assembly, permits direct syringe injection/withdrawal of sample gas or liquid without any dead space effect.
Tyre Valve (STC-CHR-S-1.12), Figure 6
The Tyre Valves are used in the same manner as one would use the valve on an automobile tyre. In Figure 6 the Chrome valve is shown. It is also available in a Nickel Plated Brass version (length 29 mm).
An optional 150 mm (6") length (threaded-twist) sample line connection (SLC-PVC/6) is also available for use with the tyre valve.
Replaceable Septum Holder (A-SEPHLD/DEL), Figure 7
When a septum is affixed to a bag with an adhesive, every penetration of it by a syringe makes another hole in the bag. This leads to continued bag deterioration and reduces its useful life. An optional replaceable septum holder allows the user to change the septum as required. Replaceable septum holders are available in the following materials: Delrin, Nickel plated brass, and Polysulfone. Stainless steel is available on special order.
Without figure:
Straight Through Connection 19 mm (0.75") ID
This STC has an inside diameter of 19 mm (0.75") and can be used when an unobstructed, low flow air or gas flow into the bag is required e.g. when collecting breathing air.
Tube Extension (STC-NPB-1/8"OD)
This STC has an outside diameter of 3.2 mm (1/8") and can be used to connect flexible tubes to the gas sampling bag.
Subject to alterations