DS095 (2) Gas Pressure accessory pack (3138) The pack contains a selection of tubing elements and valves which will allow the user to make gas tight connections to the Data Harvest Smart Q Gas Pressure sensors and interface with an experiment. Pack contents 1 m of 1 m coloured nylon pressure tubing 1 x straight push fit connector 1 x Tee piece push fit connector 2 x 3 way stop cocks 1 x 20 ml syringe 4 x small pipette points 4 x large pipette points 1
Application notes 3 way stop cocks Adapter nozzle Male port (under adapter) Control valves Female ports (under blanking plugs) White blanking plugs Specification: A three way stop cock with Luer Lock fittings universal to Luer twist and lock fittings and Luer push fit connectors. The blue tap handle (for the control valve) has moulded arrows which point to the ports that are open. Blanking caps are provided to seal off ports which are not in use. The adapter nozzle allows for fitting of oversized tubing to the stop cock. The stop cock is made of an acrylic based plastic and is therefore only suitable for water based solutions. Organic solvents will attack the plastics mix. The stop cock is not sterile and is only provided for non sterile laboratory work. The three way stop cock can be used to isolate an experiment from the sensor or allow the fitting of additional sensors to a tubing line or to allow connection of a syringe to an experiment. The female ports of the three way stop cock will link to the tapered connectors on the Smart Q Gas Pressure Sensors (models 3139, 3140, 3141, 3142, 3210) and will allow attachment of push fit Syringes. The male port (the one with the Luer twist shield) will accept tubing with a 3 to 3.5 mm internal diameter (for example the supplied). Nylon pressure tubing pushed into one of the female ports of the stop cock pushed over the male port of the stop cock 2
The nylon tubing is non transparent and coloured (red, blue or green). Specification: Nylon pneumatics pressure tubing with a 4 mm outside diameter and 2.5 mm internal diameter. It is resistant to distortion by pressure. The outside diameter of the pressure tubing allows it to be pushed into the clear supplied, and into the female ports of the 3 way stop cock. The tubing can therefore be used to make link connections between the 3 way stop cock and tubing or to make links between tubing. Lengths of the nylon tubing can be pushed through rubber bungs to make flexible connections with the clear ; this may be preferable to using glass capillary tubing in a bung. Luer twist fit Bung Female Luer port Bung Note: Rubber bungs can be drilled to make a hole using a 4 mm drill. Make sure the bung is securely held but not distorted before drilling. A 4 mm hole drilled in this way will accept the nylon pressure tubing to make a snug, airtight connection. 3
Small and large pipette points The pipette points are supplied for making connections to: 1. Rubber bungs Large pipette point Nylon or pushed into large pipette point to make a gas tight fit. 2. Plant material Silicon grease to fill any gaps Note how the taper allows the plant to be pushed in to fill the pipette tip 3. Plastic tubing the will push fit into the pipette point to make a good seal. Pipette point Push fit into 4
Push fit tubing connector (pneufit c) Straight through connector to link 4 mm nylon tubing with a simple push action. To make a connection 1. Cut the end of the nylon tubing square. 2. Push the tubing into the connector as far as it will go. 3. Pull back with a light pressure to lock the internal o ring onto the tubing. To release the connection 1. Push the plastic collar on the fitting back to the body of the connector. 2. Pull the tubing out of the connector. The straight through connector is useful for connect tubing to apparatus already fitted with 4 mm nylon tubing e.g. if a bung has the 4 mm nylon tubing fitted the connector can be used to make the link through to the PVC tubing that is connected to a Pressure sensor or stop cock. Straight connector Bung 5
To measure transpiration: Use a Smart Q ±10 kpa Differential Gas Pressure sensor. Silicon grease to fill any gaps Leafy shoot Pipette point Note: the taper allows the stalk to be pushed in to fill the pipette point Water The from the stop cock to the Sensor does not contain water. Pressure sensor A small piece of cotton wool (or similar) may need to be inserted into the tubing between the Sensor and port to prevent water from moving down into the Pressure Sensor. 6
Tubing connection examples 7
Using the tubing kit to attach Pressure sensors to apparatus Use a ±200 kpa Differential Gas Pressure sensor or 0 to 700 kpa Absolute Gas Pressure Sensor to record pressure changes for Boyles law investigations. To record pressure changes with small changes in temperature use a ±200 kpa Differential Pressure Sensor. You may want to close of one side of the Differential Sensor to make an Absolute Sensor, a piece of tubing with a 3 way tap is ideal as it will allow the pressure either side of the pressure transducer to be equalised before taking measurements. The tee connector is useful to connect an unhoused Temperature connector and a Pressure sensor to an apparatus. 8
Other examples of possible connections 9