HyQuest Solutions HS40C, User Manual, Page: 24 / 37

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Appendices
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Appendices
This chapter contains the following subsections:
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Appendix A Installing Polyethelene Tubing and Orifice Fittings
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Appendix B Using Pressure to Measure Water Level
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Appendix C HS40 Compact-DO (Dual Orifice)
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Appendix D Gas Chamber Orifice Assembly GC01P/SS
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Appendix E Typical Installations
9.1 Appendix A Installing Polyethelene Tubing and Orifice Fittings
General
The polythene tubing (3/8” OD) is available in 100m (SC078-06), 200m (SC078-18) and 300m (SC078-01) rolls. It is an
extremely durable material that has been used successfully in this application world wide for many years. The tubing
is flexible, easy to handle and can be cut with a knife. The standard copper orifice fitting is comprised of a moulded
polythene threaded cap, an orifice outlet and a tube fitting. The moulded cap will screw onto a standard 50mm
nominal bore galvanised pipe.
Orifice Fittings
The site and reference level for the orifice fittings should be resolved before installation proceeds. The length of
tubing from the HS40 Compact to the orifice should not exceed 200 metres. A suggested method for installation of the
orifice fitting is shown below. The site of the orifice should be positioned in still water, out of the main stream. The
area should be free of silting and aquatic growth. The mounting for the orifice fitting should consist of a section of
50mm nominal bore galvanised pipe threaded at one end and secured at the appropriate reference level. The securing
of the orifice mounting should be such that it can withstand the forces applied by the flowing stream and associated
floating debris.
Preparation of Orifice Tubing
Do not open the carton or remove the strapping. To prepare the roll of tubing for use, cut a 300mm diameter hole in
the centre of the cardboard carton, retrieve the end of the tubing from the middle of the coil, then cut the strapping
retaining the coil. This method will reduce the possibility of tangling the tubing. Prevent the ingress of dirt etc. from
entering the tubing, by taping up the ends. At no time should the open end of the tubing be permitted to contact the
soil.
Orifice Tubing
It is recommended that a trench be dug (minimum 600mm deep) between the equipment shelter and the proposed
positions of the orifice
The trenches should not have any low points in their length, they should have a continuous fall to the river.
Pull the free end of the coiled tubing to the orifice position laying the tubing in the trench as you go. Refer to diagrams
below.
Remove the protective tape from the end of the tubing, and push the tubing through the 50mm nominal bore pipe
mounting. Insert the tubing into the tube fitting on the rear of the orifice fitting, ensuring that both ferrules are in
place. Tighten the fitting nut. (Refer to the following diagram for tightening procedure). Place the orifice fitting onto
the mounting pipe and tighten. The tubing should be encased in a protective conduit (eg. Polypipe with junction oints
installed to allow access in the future.
Cut the tube at the coil end (tape both ends), ensuring that there is sufficient length to make the joint at the HS40S2
within the shelter.
Check the lay of the tubing in the trench to ensure that it is free of coils and kinks. Under no circumstances should the
tube form hollows where moisture can be trapped within the tube.
Lay the tubing into position in the equipment shelter as required.
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