Fluid sampling flask having cap and valve assembly
A container for collecting water samples to determine dissolved gas includes a flask-type pouch with a spout. A removable cap and valve install on the spout. The valve includes an adapter that fits with an O-ring or other seal inside the mouth of the spout. The valve includes a valve element, which can be a one-way, self-closing type of valve, that fits with an O-ring or other seal inside the end of the adapter. A cap of the container fits over the adapter and affixes to the spout to hold the valve on the spout. In use, the cap can be removed so that the valve element and adapter can be removed for filling the pouch. Otherwise, the cap can remain in place so filling can be performed through the valve element. A tamper-evident ring on the cap may be provided to ensure the integrity of the sample contained in the flask.
1. A flask for obtaining, from a source, a liquid sample having dissolved hydrocarbon gas, the flask comprising:
a pouch composed of a flexible material and being evacuated, the pouch having top and bottom ends and having an opening at the top end;
a spout sealably affixed to the opening of the pouch at the top end and defining a first fluid passage communicating with the pouch, the first fluid passage having a first inside dimension and defining a dead volume from a distal end of the spout to a proximal end of the spout toward the pouch;
a removable valve removably disposed in the first fluid passage of the spout at least to the proximal end, the removable valve defining a second fluid passage with a second inside dimension less than the first inside dimension, the removable valve with the second fluid passage reducing the dead volume between the spout and the pouch and being operable to communicate the liquid sample with the dissolved hydrocarbon gas into the pouch through the second fluid passage; and
a removable cap removably disposed on the spout and retaining at least a portion of the removable valve in the spout.
2. The flask of claim 1 , wherein the pouch comprises:
first and second sidewalls affixed along longitudinal edges; and
a bottom piece affixed to the first and second sidewalls at the bottom end of the pouch,
wherein the first and second sidewalls and the bottom piece expand outward during filling of the pouch with the liquid sample and form a base on which the flask is supportable.
3. The flask of claim 1 , wherein the removable cap comprises a tab removably affixing the cap to the spout.
4. The flask of claim 1 , wherein the removable valve comprises a first member disposed at least partially in the spout and held therein with the cap, the first member having a first external seal sealing with the spout and having a portion of the second fluid passage defined therethrough.
5. The flask of claim 4 , wherein the second fluid passage at the proximal end of the first member disposed in the spout defines a conical shape.
6. The flask of claim 4 , wherein the removable valve comprises a second member disposed at least partially in the portion of the second fluid passage of the first member and having a second external seal sealing with the portion of the second fluid passage, the second member having a self-closing valve element.
7. The flask of claim 6 , wherein the second member is affixed in the portion of the second fluid passage of the first member.
8. The flask of claim 1 , wherein the removable cap and the removable valve are removable together from the spout.
9. The flask of claim 1 , further comprising a capsule containing a bactericide and disposed in the pouch.
10. The flask of claim 1 , further comprising a filling tube affixable to the removable valve and adapted to connect to the source.
11. The flask of claim 1 , wherein the spout is usable to fill the pouch with the liquid sample when the removable cap and the removable valve are selectively removed from the spout.
12. The flask of claim 1 , wherein the flexible material of the pouch is selected to mitigate permeability and chemical interaction with the hydrocarbon gas.