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Piston or Diaphragm?

This question is about as old as both design.
What most divers don't realize are how different the designs actually are and under which conditions they perform best.

While piston regulators feature fail safe down-stream valves and open unobstructed, delivering unrivaled amounts of air while extremely responsive, Diaphragm first stages require far more parts to work, open against the flow (so called Up-Stream Valve) and deliver smaller amounts of air due to the restricted air flow in it's air-ways. Both designs have its strengths and weaknesses.

Unbalanced Piston

The Landrover of all Regulators.
This type of regulator is a reliable work-horse. With only two moving parts and minimum maintenance requirements is the Landrover of all regulators. Since the cost of ownership is minimal, it is found in most dive shops as rental regulator. It is also popular for it's small size and low weight with travelers and used as stage regulator in the technical diving scene. It is suitable for moderate to warm temperatures.
The valve mechanism opens with the flow, a so called "fail safe - or - down stream valve". This valve is able to open unobstructed and delivers large amounts of air on demand.
Since the design is unbalanced, the tank pressure influences the Intermediate Pressure (IP) slightly. The IP drops as the tank pressure decreases. This in general results in slightly higher breathing resistance towards the end of the dive.
The design has a open water chamber, allowing water to enter and act directly onto the piston, compensating for depth and adjusting the Intermediate Pressure accordingly.

The most popular model in this category is the Scubapro MK2 which was first introduced in 1963 and has been updated over the years. It is currently available as DIN 300bar, Yoke 200 bar and Nitrox Version to 100% O2.

Scubapro MK2 plus

Balanced Diaphragm Regulator

The Balanced Diaphragm Regulator is a popular design, working on the Upstream Valve Concept.

This type of valve opens against the flow of the air. The design is far more complex as compared to the Unbalanced Piston Design, resulting in 7 or more moving parts. A pin which runs through the center of the Orifice, reducing it's opening controls the valve. This results in a reduced airflow as compared to other regulator designs.

The advantage of the design lies in a fairly compact size. The absence of a water chamber means no water enters the first stage reducing the risk of icing. The Water pressure is transmitted through a flexible Diaphragm.

In our experience the complex internal structure of these stages attract and accumulate more dirt, dust and debris as compared to other designs resulting in significant internal corrosion if not handled properly or if poor air quality is used.

Scubapro MK11 LIGHT

Environmentally Sealed Diaphragm Regulator

The Environmentally sealed Diaphragm Regulator is a basic upgrade from the open Diaphragm Regulator Design.

It features a second diaphragm which seals the otherwise exposed spring against the environment, sealing all moving parts from the water, leaving only the external Diaphragm exposed. This also results in a lower temperature within the first stage as the water is not able to warm the stage as effective. This can result in serious internal icing of the stage if the breathing air is humid due to not properly maintained filter systems of the compressor system used filling the tanks. This fully environmental sealed design is suitable for extreme contamination, liquids other than water and Water temperatures below 4 degrees Celsius in combination with suitable air quality.

In some cases the space between the two Diaphragms is filled with oil or other liquids making the regulator incompatible with Nitrox

There is no significant performance difference between standard Diaphragm and Environmentally sealed models. Some manufacturers achieve a slightly better response to IP changes by using a thinner internal Diaphragm.

Corroded Environmentally Sealed First Stage Interior

Over-Balanced Design

The goal of the so called "Over Balancing / IP Boost / Intermediate Pressure Amplification" is to reduce the breathing effort with increasing depth. It is offered by many different manufacturers.

In Diaphragm First Stages it is in general achieved by using a larger size external Diaphragm as compared to the inner one. With increasing depth and therefore increasing ambient pressure, the Intermediate pressure is artificially increased beyond the normal compensation for the depth. The result is a reduced breathing effort at recreational depth but renders the design unsuitable for technical diving as there is no limitation to the increase with increasing depth, risking failure or free-flow of the system.

Balanced Piston Design

The Regulators with Flow-Through-Piston Design have the highest air delivery in the market due to the large piston travel and wide, unobstracted opening of the valve assembly allowing vast amounts of air to be delivered on demand. The valve works with the "fail safe" down stream principle and there are only two moving parts in the design making it extremely reliable.

The flow-through-piston out-performs diaphragm regulators especially at low tank pressures with it's wide opening valve assembly allowing sufficient air to flow to keep the Intermediate Pressure stable and retain performance even with more than 1 second stage in use.

As in the standard piston regulator, the water pressure acts directly onto the piston. In older designs oil or silicone grease was used to transmit the pressure. Current models allow water to enter the water chamber and different technologies are used to prevent icing of the regulator through insulation and non-stick materials.

Some models feature ribs to increase the surface and dissipate the cold more effectively enabling the use in cold-water conditions. In most cases LP-Hoses are connected to Swivels allowing flexible hose routing.

There is no depth limitation for this type of regulator as the water pressure increases the Intermediate Pressure linear.

Scubapro offered their first flow through piston design in 1964 with the MK1, followed by the MK5 in 1965 with Swivel LP-Connector

Scubapro MK25 Black Tech with black Titanium Nitride PVD coating

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MK11 LIGHT / C200

C200 Octopus

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The Main Phone Number of Pacifica Dive Manila has changed.

The new number is (+63 2) 8464 220

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PACIFICA DIVE just finished the implementation of a Yacht-Diving-System.

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ON SALE: EXD BACKPLATE SYSTEMS
- valid until supplies last -

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Dive Log Book, developed by DNA BLU in partnership with SCUBAPRO UWATEC, allows you to import and display dive profile data from SmartTRAK and DataTRAK files from your PC, transferring them to your iPhone. This application allows divers to transfer and carry dive data from all dives recorded using SCUBAPRO UWATEC dive computers (Aladin, Smart and Galileo series). It also lets you manually insert dives on your iPhone.

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FIND IT HERE

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If stored unattended or used as check-in luggage, its top D-Rings provide security feature by giving provision for a padlock or cable-tie. Its 2 side D-Rings provide further fastening features to ensure safe travel on the back of a kayak, motorbike or various other situations.

The Octo Dry Bag is priced from 590PHP- 890PHP depending on size. It is available at PACIFICA DIVE and many of it's retail partners.

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Just a part of our Scubapro collection.

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What we take for granted today, was 25 years ago a novelty.
The technology to combine a balanced first and second stage was marked in 1985 by Scubapro Europe with the release of the Mark X DUAL BALANCED.
This version was only sold in the european market and only if purchased in this combination, the Mark X would be marked as DUAL BALANCED to signify that both stages are balanced.

The First Stage, a balanced Mark 10 would become one of the most produced and most copied designs in the market.
The balanced MK X Second Stage laid the foundation for all Scubapro Balanced Second Stages today.
It was followed by the BA - Balance Adjustable, the G250, the S-Series and the new A Series.

We just received one of these sets in excellent conditions and it will be displayed in our retail store soon.

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How to rinse Dive Equipment - Part 1

REGULATOR

My regulator just turned 19.

Yes, 19 years ago I went into the local SCUBAPRO dealership in Germany and bought my first set of MK10 / G250.
After the first year the local technician showed me what my thorough care & rinsing had resulted into.
The filter was green of corrosion and there was corrosion inside the gauge as well. I had drowned my regulator.
The technician had to teach me  the right way to take care of the set.
Since then, the regulator has worked flawlessly and never left me without breath.

The need to rinse our dive equipment is apparent, especially when used in seawater.
If left un-rinsed, the drying saltwater becomes more and more concentrated and therefore even more aggressive. Metal parts will corrode and the drying salt leaves sharp crystals. Between moving parts these dried salt crystals grind down O-Rings and mix with lubricants.
Even hoses and other rubber parts are never spared.

But "rinsing" our equipment is not as straight forward as dumping the gear into a fresh-water bin and hoping this will do.
Actually this practice is one of the most common and at the same time potentially most harmful for the gear.

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When rinsing the regulator after a day of diving the aim is to clean the regulator of salt and dirt.
We intend to do good and not harm to the equipment.
What we want to avoid at any cost is water entering into the high pressure and intermediate pressure part of the regulator.
The installed "dust caps" - as the name suggests are often not waterproof and therefore are insufficient to fulfill this goal.

- Do not allow  water to enter the 1st stage and intermediate pressure area of the regulator from either 1st stage or 2nd stage
- Do not shake the 2nd stages in the rinse-tank as this will push the purge and open the valve mechanism, allowing water to enter the hoses.
- Do not dump or dunk the 1st stages into the rinse bins, especially if the air inlet is not 100% sealed.

So how do you rinse your regulator properly? How do you do it right?
The best way is to rinse the regulator under flowing water or to keep it pressurized when submerged (i.e. still attached to a scuba tank with the tank valve open).
When using flowing water,  rinse around the first stage tank connectors, plastic covers, swivels and water / spring chambers.
Rinse thoroughly under hose protectors, gauge covers / consoles, inflator hose mechanism.
Let water flow into the mouth-piece without pushing the purge button.
Rinse the hose swivel connectors, and any opening on the 2nd stage.

What if water has accidentally entered the set?
Remove the High-pressure  hose from the first stage to prevent the water from advancing into the gauge under pressure.
Attach the set to a scuba tank. Purge the 2nd stage and Octopus while slowly opening the tank. Repeat as necessary.
You will see the water mist spraying out. Repeat in small bursts for a while. Do not purge for prolonged period of time as the water will just freeze and not get out of the system.

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We have received over the last four weeks numerous dive computers of different brands with the unpopular "ERR" Display Reading.
Most customer complaints were "Computer eats Batteries" - or high power consumption in technical terms.

PACIFICA tests all computers for power consumption and accuracy before returning the unit back to the customer. We have our own UWATEC Pressure chamber so don't be surprised when the log shows a 150ft dive with deco stop after the service.

After removing the wrist straps and the old batteries the testing started.
The units were tested for power consumption which in rare cases can drain the batteries and needs internal fixing. Two units were identified with abnormal high consumption. None needed a PCB repair.
In both cases salt & mineral build-up on the wet contacts (see picture) were responsible for draining the power within days. The owners would have saved a lot of headache and some batteries by proper rinsing and cleaning the computer after diving.

Of the eight remaining computers one was fitted with the wrong size/type battery, explaining the malfunction.
The remaining seven units all came with the same brand of battery.
I don't really want to mention which brand it is as I think that all are fakes and not the original branded.
All were CR2450 and were supplied by the same source.

So if your computer runs out of battery much faster than acceptable it might need some attention and a brand new, genuine or branded power-source.

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Filmed by Alexander Abela and Herbert Nitsch in Okinawa during the Freediving World Championship 2010

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Since Johnson Outdoors acquired Seemann Sub in 2007 many things happened.

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If you haven't noticed them yet,
PACIFICA offers Stickers from FUN FRUITS to SERIOUS VOODOO Gas.
We also offer customized vinyl stickers up to 28" in width on various different materials like clear, white, colored, metallic and other substrates.

If you have requirements, small or large orders, please let us know...

Other related products:
Die Cut Stickers, Name Stickers, Boat Names printed or Cut, Tank Wrap stickers, Content Stickers etc...

Name it, we make it!

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