(Please refer to the diagram enclosed)
The systems with MPS static mixers enable you to prepare ternary (Trimix, Heliair) as well as binary (Heliox, Nitrox) mixtures. They are easy to install and have enormous advantages to their convenience of use. Their shape, patented all over the world, guarantees mathematically predictable mixtures (by specific computer software) with a minimum pressure loss.
The Mixer is composed of a series of mixing elements placed in series in a tubular setting. Mixing is based on the division and radial deviation of the fluid by each element. At the inlet mouth the system sucks ambient air through an antiparticle filter (F). The air is transferred to the first mixer (M1) where is located the injection of oxygen. At the outlet of the first mixer the Nitrox obtained is transferred to a second mixer (M2), where we have the injection of helium when required (He-I). The Trimix obtained is finally transferred to the compressor intake through a suitable tube (P).
Both the helium and the oxygen supply circuit are equipped with a suitable micrometric valve placed in the upper part of the mixer injection for the gas flow regulation (CV1 for oxygen e CV2 for helium). The regulation valves have to be supplied with gas at pressure of maximum 8 bars. This pressure can be regulated through the valves (DV1 and DV2) of the reduction group of the oxygen and helium cylinders.
DV1 – DV2 PRESSURE REDUCING VALVES
The system is equipped with an oxygen analyzer with 3 fuel cells and a helium sensor (optional). On the analyzer display it is possible to read both, what is indicated by Nitrox oxygen cell (S1) produced by the first mixer, and what is shown by the Trimix oxygen cell (S2), at the outlet of the second mixer. These indications allow you to visualize the values of the mixture required. In the lower part of the mixer is inserted o jacket connection (S3) that can be used to analyze the mix in the tank.
N.B. Due to the behavior of the pure gasses, it is always compulsory to analyze the mixture obtained, in order to be able to correct potential differences and then gauge the system.
Control Panel and Mixture Display (MCU)
A very efficient safety system is available on the Mixer. It is provided with two electro valves (SV1 and SV2) which are usually closed and prevent the oxygen and helium to flow into the system. The valves can be opened only by closing their circuit with the key switch K. Moreover on the Mixer there is a cable that supply a relays located inside the mixer that has to be connected in parallel to the compressor switch. This let that the oxygen valve could open only when the compressor is operating. Than this safety system, first of all prevent the use of Mixer at personnel without key, (but the compressor can operate all the ways), second, prevent the mixing system will be filled with pure gasses, thing that is dangerous related to oxygen and expansive for helium.
Moreover, if the limit in percentage is exceeded for the oxygen, the Mixer itself turns off the compressor. (Contact NO located inside the Mixer).
Another possibility is changing this safety system with a bulb that feel the decompression depression in the intake filter when the compressor is operating.
NB: All the electrical connection has to be made by qualified technicians.
SAFETY SYSTEM
In the picture below you can see the clutches for Oxygen and Helium placed on the electro valves supply by 24 v/Ac transformer inserted inside the analyzer.
The processor is also programmed to stop the Oxygen flow and turn off the plant when the percentage of Oxygen rise more than 45% to prevent damage to the compressor due to a work with a too high level of Oxygen.
If it may happen a buzzer alarm start and a red led turn on, meanwhile the Oxygen flow is closed and the compressor is turned off.
On the display you can choose if reset the system or go on mixing after lowered the Oxygen level through the Oxygen flow regulation valve CV1. ( In between the valve stay closed).
This alarm level is set for both Oxygen cell.
Moreover the display allow you a perfect visualization due to backlight.
Enclosed with this manual you will find a pattern with a flow diagram to make easier the use of the Mixer.
When the key lock is in position “OFF” (non operating) or when you want to turn it off, the following conditions must be verified:
To refill the tanks with air no further operations are required. Just verify the conditions listed for the OFF position. The compressors can be operated in the usual way.
Note: starting the compressor means that the electricity is supplied to the Mixer. But the OFF position of the K switch don’t get power to the valves SV1 and SV2, together with the clockwise closing position of the valves SV1 and SV2 prevent the flow of oxygen and helium into the mixing system.
Check the system seal and fix the potential leaks before operating the system.
NITROX TANKS REFILLING (OXYGEN BETWEEN 22% AND 40%).
To refill the tanks with Nitrox, first verify the percentage of oxygen required. Analyze the tank with the Mixer analyzer, check the tank pressure and than put these values in the Mixer’s software
NITROX RELOAD POSITION
iP Initial Pressure
iEAN Initial Oxygen %
fP Final pressure required
O2% Percentage of Oxygen to use for refill required
The values of Oxygen that is indicated on the top right of the display during the refilling operations are the values that we have to fix and hold to get the final mix required.
Note: if the results of the calculation of the percentage required is 21%, the tanks can be directly refilled with air; instead if the results is lower than 21%, it means that there is too much Oxygen in the tank, therefore, if you want to refill it, you have to bring it to a lower pressure by partially emptying it. To calculate this it is enough to reduce the value of the internal pressure set in the software up to the point we read 21% in the lower line on the display.
PREPARATION
Once the percentage of the oxygen required has been calculated, you can start the refilling operations. Operate respecting the following order:
REFILL
To refill the tanks with Trimix, first verify the percentage of oxygen and helium required. Analyse the tank with the Mixer analyser, check the tank pressure and than put these values in the Mixer’s software
TRIMIX RELOAD POSITION
iP Initial Pressure
iO2 Initial Oxygen %
iHe Initial Helium %
fP Final pressure required
fO2 Final O2 required
fHe Final Helium required
O2% Percentage of Oxygen to use for refill required
He% Percentage of Helium to use for refill required
The values of Oxygen and Helium that are indicated on the top right of the display during the refilling operations are the values that we have to fix and hold to get the final mix required.
Note: if the results of the calculation of the percentage required is 21%, the tanks can be directly refilled with air; instead if the results is lower than 21%, it means that there is too much Oxygen in the tank, therefore, if you want to refill it, you have to bring it to a lower pressure by partially emptying it. To calculate this it is enough to reduce the value of the internal pressure set in the software up to the point we read 21% in the lower line on the display.
PREPARATION
Once the percentage of the oxygen required has been calculated, you can start the refilling operations. Operate respecting the following order:
NOTICE: At the moment of installation, the technician from MPS will control the relation between loading pressure and percentage of Helium. In fact, in relation with the kind of compressor and the level of usury, the technician could verify an higher loose of Helium in relation with air. If this situation happened he can gives you some advice to get a solution.
In the model B-Mix Diving, a single mixture model is available also an environment control of Oxygen to prevent that a loss of gas could saturate the environment increasing the risks for the blender. (This is for close rooms with stock tanks).
The sensors can read a lower level or a higher level of Oxygen in the working environment (setting are low 18%, high 23%).
The fuel cell is calibrating together with the others automatically when is active the function CALIBRATE.
The Oxygen value in the environment will be visualized on the display for 10 seconds, but is operating even if not shown.
Whenever the level of Oxygen exceed the setting value the Mixer indicates the warning closing the gas supply and turning off the plant.
VISUAL OXYGEN ENVIRONMENT LEVEL (optional)
Together with the wire for the serial connection to a PC, is supplied a software that can print a label from the function ANALYSE that is the one that you use to analyze the tank after the refilling procedure.
From the print you get two stripes in which are printed: MOD, EAD, percentage of Oxygen for Nitrox, date, the brand of diving or refill station and a place for the sign of the operator or the customer.
On Trimix analysis we will have instead of MOD and END the O2%, He%, date, the brand of diving or refill station and a place for the sign of the operator or the customer.
One sticker is placed on the tank and the other on the refill station logbook.
It is possible also create a file to save a logbook on the PC.
All the Software upgrade will be available on the internet or send free of charge to all the owners of a printing software.
In the version MCU is it possible to get the Helium sensor as optional to check the mixture at the outlet of the compressor during the refilling and also to do it at the end with the possibility to print the analysis with both gases.