The DTB5C is an air driven booster designed specifically for Oxygen service. It is well suited to both CCR and Open circuit divers. It's unique design ensures there will be no cross contamination between the air driving the booster and the Oxygen being compressed. Therefore the booster can safely be driven from a low-pressure compressor, which is likely to pass oil in the air stream in the absence of filters.

Oil lubricated 2005

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Mk1 DTB5C 2007

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Mk2 DTB5C 2009

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Mk3 DTB5C 2019

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DTB5C Design

The design of the DBT5C means it is economical on drive gas as it uses a return spring and the incoming Oxygen pressure to return the piston back to the top of the stroke, which would otherwise require drive air directed below the piston to provide the lift. With this design, air is only supplied to the top of the piston, thereby providing the desired separation between the air and the Oxygen. The air motor section is linked to the Oxygen piston via a pushrod, through a vented chamber, which provides another level of separation.

The DBT5C will boost air, oxygen, helium and argon to a maximum pressure of 270 bar. The Oxygen piston/cylinder is identical to the HP stage on the DTB10C electrically driven booster, which is rated to 350 bar and cycles at 350 strokes/min. The DTB5C will cycle at a maximum of 190 strokes/min to 250 bar. There is no need to restrict the speed of this booster and indeed it is recommended to always run it at maximum speed. The waste air ejected from the air motor is very effectively routed around the Oxygen cylinder to provide very efficient cooling. Keeping the Oxygen seals cool prolongs the service life and provides a cool transfer of gas.

Using the Booster

The DTB5C booster is normally supplied as a "Turnkey system ready to use". It takes just a few minutes to assemble. The booster is provided with a back-plate which will either screw to the wall, or Cam-band to a diving cylinder for convenience. Next, fit the 2 x 1.5m gas hoses to booster inlet/outlet. Fit your Oxygen supply cylinder adapter to the inlet hose, and the gauge block to the outlet hose and your target cylinder. All types of cylinder adapters can be supplied and will be discussed at the point of ordering. Air is used to power the booster which can either be taken from a Scuba cylinder, or a 10 bar Low pressure compressor(only one method per system with other an optional extra). The Scuba option is a 106cm air hose which fits your own SCUBA Regulator LP port and a Quick connect fitting onto the booster air drive inlet. The LP compressor option is a standard PCL air line adapter. You are now ready to start boosting. The booster has a non-return valve at the inlet and outlet so no other non-return valve is required in the system. Opening the Oxygen supply cylinder slowly is perfectly acceptable during the initial decanting Procedure so a needle valve is not required. Once the gas pressure has balanced across the Supply and the Target cylinder you then open your Scuba air cylinder valve to start cycling the booster to transfer the gas. The outlet charging block supplied includes a 63mm gauge so filling pressure can be monitored. Once the fill is complete, Isolate cylinder valves and relieve pressure at the charging block bleed screw.


Air motor section

Regular servicing of the air motor section is limited to the lubrication of the timing shuttle located in the top of the booster (using the A500-LK service lube supplied. The booster package includes a tube of the A500-LK lubricant which should suffice for approx 3 years. The booster is built with a charge of lubricant with a service expectation of 80 hours. The re-lube procedure takes no more than 5 mins. It is understood than anyone maintaining a CCR can comfortably complete a full service on the air motor section. No special tools are required. Using the A500-SK seal kit a complete change of all O-rings seals and guide rings can be undertaken with Technical support provided by Cetek Ltd if required. Out of hours Tech Support is available 7 days a week.

Oxygen compression assembly

The Oxygen cylinder is made from high-grade stainless steel, heat-treated for extra hardness. The inlet/outlet non-return valves use stainless steel seats with Ceramic valve balls, which remain spherical considerably longer than stainless steel types, so overall we have a very robust piston cylinder arrangement that is rated to 350 bar. The Oxygen seals are of a composite self-lubricating material, held under spring tension on the piston. This unique design actually expands the seals as they wear which provides a very long service life. To change the seals require two screws to be undone to detach the piston/cylinder assembly from the air motor section. The piston can then be withdrawn from the cylinder. Replacing the seal set is very simple procedure so long as Oxygen clean procedures are obeyed. A fully detailed drawing of the seal arrangement is available in the manual.The Oxygen seal kit is part no 1412C-OX.

The DTB5C system - What's in the box?

When ordering your booster system we allow for one inlet adapter referred to as your "Primary Inlet Connector", and one outlet adapter as the "Primary Outlet adapter" to form the standard package. Any connector type in use throughout the world can be supplied and selected using the drop down menu on the order form. If you require a 2nd inlet/outlet adapter then this is referred to as the "Secondary" adapter as is a charged as an optional extra. Generally, secondary adapters are simply screwed onto your Primary adapter for quick and easy use. Instances were a 2nd inlet adapter be required might be that in your Gas Filling station you draw your Oxygen supply from an Industrial supply cylinder(BOC,Air Liquide etc), but when traveling a 232 bar Din cylinder is used for the supply source. All these details are discussed at the point of placing your order with us.

The package is as follows:

1 x DTB5C gas booster

1 x Inlet adapter -typically 232bar Din, UK Bullnose, CGA540, W21.8 x 14

2 x 1.5m Stainless steel braided hose WP 276 bar

1 x Outlet connector and gauge block, bleed screw with 63mm gauge with rubber boot

1 x 1m Scuba air drive hose with QC connector to booster and 7/16" UNF male to fit the LP port on a Scuba 1st stage

1 x pack of service lubricant (3 years supply)

1 x A4 paper copy manual with full parts diagrams and numbers

DTB5C specification

Booster ratio 1:36 Describes the ratio between the size of the air Piston and the Oxygen piston

Boost ratio. Describes what pressure is achieved from the inlet pressure. Be aware that this figure is invariably the mathematical probability and not what is actually achieved in worthwhile and workable conditions. The ratio’s quoted are what the booster actually produces in a valid filling operation.

Oxygen 5:1 Helium 4:1 e.g. 50 bar inlet with Oxygen produces 5 x 50 = 250 bar.

Minimum inlet pressure 20 Bar (290 psi)

Maximum outlet pressure 270 bar (3916 psi)

Drive Air gas pressure required 6-10 bar Max (87-145 psi)

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Big Sam Helmy mixing gas for the 2019 World Record Deep Dive by Ahmed Gabr to 332m. The two DTB5C boosters were used to transfer all the Open circuit Oxygen and Helium required by the entire dive team which amounted to a considerable volume of gas.

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