Today I am going to describe some equipment with difficult ethical background. Officially these are named “pressure relief systems/mattresses/seats”.
The are situations where human body has lost its mobility. Straight said: somebody has managed to break his backbone, or, a brain stroke has happened. Type 2 diabete modifies the situation even worse. The autonomy of those impaired persons is very limited, while in modern western society it is a tabboo to even speak about euthanasia (gee! The Greek language still does have words for these situations…). However, the device could not be assessed as a proper life support device, but almost that 🙂
While tabboos are kept and euthanasia disallowed, a new risk appears for patients chained to the bed – pressure ulcers, or “bedsores” or “pressure sores”. Thus the Device (TM) will be bought or rented which cures the psychological side of the situation – leaving yhe victim without the possibility to choose passive euthanasia through the sores complications. While the devices are regularly serviced, they still do not write down the number of deaths the device has witnessed.
There are some interesting applications of pumping technology (water cooling for computers, technology assisted fuel thefts etc) thus I keep an eye on available pumps. While the device was priced at 15€, I rejected it, but when the price dropped down to 7€, my curiosity took over. Considering how rare these devices are and taking into account the existance of ethical tabboos keeping people away from death related issues, I decided to document my little investigation to an extent.
The PDF describing the purpose of these products is downloadable from the manufacturer. The overall idea of the device is very simple – it is similar to the swimming mattress, but there are several air chambers and the pressure is constantly alternating between these. Basically, it is a slow motion massager.
This is how the control device looks like.
The inner part of the device is relatively complex. It seems to me that pneumatic design is an almost lost art these days.
There are two “drivers” in the device. The first one, let’s compare it with the lungs, is a vibration type pump, capable to create 30-80 mm Hg pressure (read: not too much). Somewhat similar pumps are used for aquaria.
Another “driver”, let’s compare it with the heart, is the program clock defining the mattress alternation rhytm. It takes several minutes for the distributor to make a full 360 degree rotation.
The actual programming of the device is made in hardware – it is mechanically defined by a special disk. It ensures the pressure between the two sections alternates itself, once being directed to output A and then both, and then to output B.
The motor behind the program clock is astonishly similar to the motors found in old washing machines.
The pressure of the air flow sent to the mattress, can be regulated.
The regulator is a very straightforward one – the less air escapes the regulator, the higher is the pressure. Thus, low pressures are accompanied by a characteristic snake hiss.
This is the signal board. Should the pressure drop too low (e.g. the mattress got punched through), it emits a sharp warning tone. It is possible to switch the alarm off.
On the output of the device, there are two pneumatic joints.
As described above, the mattress has two independent sections (we call them A/odd and B/even). Defined by the program clock and master program disk, the pressure could persist in ribs A, ribs B or both.
Last but not least, the mattress is built so bulletproof that chemical and psychological contamination can be washed off easily. The pillowcase can withstand up to 80 degrees Celsius when washed, could your clothes?
Vot sihukese riista on nad välismaal välja mõelnud. Ese on 15 aastat vana, kuid täiesti töökorras. Kui tead kedagi, kes seda minust rohkem vajab, anna aga teada!