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FULLY-CLOSED REBREATHERS
[Cis-Lunar MK5P]

A.P. VALVES INSPIRATION
The BUDDY Inspiration Closed Circuit from A.P.Valves is the first CE approved closed circuit breathing system:
approved to 50m with Air as the diluent gas and 100m with Heliox. The dual microprocessor oxygen-level controllers automatically maintain a constant partial pressure of oxygen giving outstanding gas duration and an optimum breathing mix at all depths.

This gives all the benefits of Nitrox without the pre-mixing and without the depth limitations.
Oxygen-rich breathing throughout the dive and the super-oxygen-rich gas mix during decompression drastically reduces decompression obligations on every dive - without pre-mixing, without carrying extra cylinders and without gas-switching. With No-stop times dramatically increased, all the benefits of perfect buoyancy control, warmer, quieter diving and with no bubbles to keep wildlife away, diving with the BUDDY Inspiration Closed Circuit is going to bring a whole new experience to Sport and Commercial diving as we know it.

With the Inspiration Closed Circuit exhaled air goes into the right hand counterlung then over the shoulder into the bottom of the scrubber unit. It then passes through a Sofnolime filter which absorbs the carbon dioxide before entering a mixing chamber where 3 individual oxygen sensors measure the partial pressure of oxygen (ppO2). The electronic controller is a voting logic system which automatically instructs the solenoid to inject oxygen into the mix to replenish the oxygen the diver has metabolised and maintain the ppO2 at the chosen Setpoint. The replenished breathing mix passes into the inhalation counterlung to repeat the cycle.

Dive duration is limited by the CNS oxygen toxicity clock and the life of the CO2 Scrubber. The oxygen exposure limit varies according to which Setpoint ppO2 is selected. The Inspiration has two default Setpoints - 0.7bar and 1.3bar - and these can be altered in Menu Mode to setpoints ranging from 0.5bar to 1.5bar. Therefore you can tailor the setpoint to suit the mission. To give some examples:- working to the NOAA Exposure Limits - at a Setpoint of 1.3bar dive duration is limited to three hours (or three and a half hours per day). However, if you wanted to increase duration you could dive, for example, on a setpoint of 1bar and increase your oxygen toxicity exposure limit to five hours.

The duration of a Sofnolime fill depends upon factors such as the individual diver's CO2 production rate, water temperature, work rate and so on. In the recent independent testing for CE certification carried out at the Ministry of Defence Research Establishment, Alverstoke, the Inspiration's scrubber duration was 3 hours in cold water (4 degrees C). The tests simulated a breathing rate of 40 litres per minute (lpm) RMV, and a CO2 production rate of 1.6 lpm.

By recirculating the exhaled gases, removing the CO2 waste product and replenishing the oxygen the Inspiration limits the gas removal from the oxygen cylinder to the same volume that we consume for metabolism. That is, between 0.5 and 3.5 litres per minute depending on the person and the work rate. Mr Average consumes approximately 1 litre of oxygen per minute and in general, women consume less. Filled to 200 bar the Inspiration's 3 litre Oxygen cylinder contains 600 litres of oxygen. Therefore, at the average consumption rate of 1 lpm, theoretically, each fill should last 600 minutes or 10 hours. In practice some gas is lost during mask clearing and extra O2 is added during ascents. Nevertheless, it is realistic to achieve at least 6 hours diving from one 3 litre cylinder of oxygen!

CIS-LUNAR MK5P
[A.P. Valves Inspiration]

Description - NOTE: Unit not currently available

The MK-5P is an electronically-controlled, mixed-gas, closed-circuit underwater breathing apparatus (CCUBA), commonly referred to as a 'rebreather'. Unlike conventional SCUBA systems, which waste enormous amounts of gas with each exhaled breath, the MK-5P recirculates the exhaled gas, removes CO₂, adds oxygen, and returns the gas back to the diver. In doing so, the MK-5P uses the available gas supply with nearly 100% efficiency.

Because of this greatly increased efficiency, a small (13.3 cf) cylinder of oxygen is sufficient to sustain a working diver for as long as 6-12 hours underwater, regardless of depth! Moreover, the triple-redundant electronic control system automatically maintains the partial pressure of oxygen (PO2) in the breathing gas at an optimal, user-selectable level, thereby extending no-decompression times (especially on multi-level dives) and minimizing decompression obligations. The near absence of bubbles (except during ascent) allows divers to approach a wide variety of marine live with much greater proximity than possible with conventional (open-circuit) SCUBA.

Designed for the professional scientist / explorer and for diving operations where exceptional reliability is required, the MK-5P will be used for extended submerged times, great depths, and diving in overhead environments where direct ascents to the surface are not possible. The system includes a redundant, onboard constant-PO2 decompression computer, which provides the user with immediate and projected decompression requirements based on real-time breathing gas composition. The system further allows for interactive changes in the breathing gas mixture during the course of a dive, in order to permit use of nitrox, heliox, trimix, pure oxygen, and alterations of the PO2-setpoint. State-of-the-art electronic feedback is provided to the diver via redundant triple displays. The system may be easily operated in manual mode using Cis-Lunar's patented front-mounted manual control console in combination with a backup oxygen partial pressure display.

The MK-5P rebreather design represents a significant improvement over existing rebreather technology and achieves a profound reliability not previously available. The MK-5P is founded upon four generations of prototype designs built by Cis-Lunar, which have been subjected to literally thousands of manned testing hours, including several major exploratory expeditions in a variety of diving environments. One unit supported a submerged diver for over twenty-four hours, non-stop! The Cis-Lunar MK-5 series rebreather and its predecesors have been used by underwater speleologists, diving scientists, underwater photographers, military divers, advanced technical divers, and will ultimately include the average sport diver.

In comparison with the past and present existing CCUBA devices, Cis-Lunar has developed substantial technological advantages. Take special note of the significant reduced operating costs and resulting quick payback for the purchase of a Cis-Lunar CCUBA system.

Specifications

Operational Comparisons of the MK-5P vs. SCUBA.

* Based on twin 120-cf SCUBA cylinders.

Features

Basic Hardware
The MK-5P is equipped with a high-quality harness system that attaches to the backplate via adjustable brackets, allowing optimal placement on divers with different physical builds.

A rugged buoyancy control device (BCD), providing a maximum lift of 60 lbs (28 kg), is included with the MK-5P.

The shell is constructed of durable high-impact ABS plastic and attaches easily to the backplate via four stainless steel snaps. It is specially molded to accommodate two standard cylinders, up to 100 cf, which can be attached with standard webbing cam-lock bands through four sets of slots (two sets for each cylinder).

Breathing Loop
The MK-5P incorporates a patented mouthpiece design with an integrated open-circuit regulator in the rebreather mouthpiece. With the quick twist of a quarter-turn valve, the diver can immediately switch from closed-circuit breathing mode to open-circuit breathing gas, without removing the mouthpiece or full-face mask.

Durable, yet flexible, the breathing hoses are both crush-proof and nearly impervious to failure. As added protection, each hose is shrouded in a ballistic sleeve, which protects them from abrasion.

Contoured, ergonomically designed over-the-shoulder split counterlungs reduce breathing effort by remaining in near hydrostatic equilibrium with the diver's lungs. Mounting brackets for the counterlungs are adjustable, allowing optimal positioning of counterlungs for divers of different physical builds.

Specially-designed water traps at the interface between the breathing hoses and the counterlungs divert water from condensation or leakage at the mouthpiece directly into the counterlungs, where it can be purged from the loop.

The modular and easily removable CO2 absorbent canister is of stainless steel construction. In the event of a complete breathing loop flood, the CO2 absorbent material remains completely dry, enabling the user to effect a full recovery of the rebreather in closed-circuit mode. The flood-tolerant nature of the canister allows Lithium Hydroxide (LiOH) to be safely used as a CO2 absorbent material for extended and cold dives of up to 14 hours long.

Gas Supply System - The basic gas supply of the MK-5P rebreather includes one 20 cf diluent cylinder and one 13.3 cf oxygen cylinder. The shell of the MK-5P is designed to accommodate the easy mounting of two additional cylinders, from 13.5 to 100 cf capacity each.

Highly reliable and dependable oxygen injection solenoid valve ensures constant PPO2 setting, no matter how hard the diver works.

An adjustable automatic diluent valve (ADV) automatically adds diluent to the breathing loop whenever the right counterlung is bottomed-out.

A multifunction gas control manifold provides easy control of gas supplies to the rebreather. Valves allow the user to switch both oxygen and diluent from the respective onboard gas supplies and offboard gas supplies (the latter attached via quick-disconnect fittings). It also allows easy manual addition of either oxygen or diluent, and includes a valve to immediately cut-off the supply of oxygen to the solenoid valve in the unlikely event that it fails in the open position.

The gas supply to the integrated open-circuit regulator is always maintained as the active diluent. The diver can access all onboard and offboard gas supplies through this mouthpiece via the gas control manifold.

Electronics - The "brains" of the MK-5P consist of an integrated triple-redundant, networked computer control system. The computers allow for users to change a wide variety of parameters during the course of the dive via a comprehensive menu system, display critical dive information to the diver such as PO2 readings of each sensor and average PO2 reading, current PO2 setpoint, active diluent, current depth, maximum depth, dive duration, decompression information, cylinder pressures, remaining CO2 absorbent time, ascent rate, water temperature, and a host of other information such as system warning messages.



The primary display screen consists of a high-contrast, back-lit liquid crystal display (LCD) with adjustable contrast control, providing dive data and menu selections to the diver in bright or dark conditions.

A Redundant Oxygen Display (or ROD) for PO2 display on the back of (but completely independent from) the LCD display shows direct analog readings of all three oxygen sensors simultaneously. This allows verification of the readings indicated on the primary display, as well as a means to monitor actual PO2 during manual control, in the event of a computer system failure.

A heads-up display (HUD) communicates to the diver via three tri-color LEDs critical information about the PO2 in the breathing loop, decompression ascent rates, and alerts the diver of waiting system messages. Brightness of the HUD LEDs is adjustable via the computer menu system.

A pair of buddy lights on the back of the MK-5P communicate the PO2 status of one diver to his or her buddy (green for O.K., flashing red for low PO2, solid red for high PO2).

An audio alarm system warns the diver of dangerously high or low PO2 levels in the breathing gas.

Independent and isolated power supplies for each of the processors, solenoid valve, and backup systems provide maximum redundancy.

MK-5P Mixed Gas Electronic CCUBA
(Closed-Circuit Underwater Breathing Apparatus)
Product Specifications

Ascend to Surface