Russian Oxygen Booster Pumps

The need to boost gas is an obvious one for any diver using a rebreather. For the SCC diver, carrying larger diameter cylinders filled with the correct mix when making multi-dive trips is an obvious alternative to needing to carry a load of pre-filled smaller cylinders, and for the CCR diver being able to boost 02 to 3000 PSI/ 200 BAR when getting gas from a supplier at 2200 PSI is a real advantage. Not to mention the needs of mixing and then boosting diluent gas, etc. The booster pump really is an integral part of a properly equipped rebreather divers inventory.

The Russians copied the German Draeger system of booster pump. The smaller KN-3, a manually operated pump, is a functional copy of the German "Frau Dreager". The KN-4 has the same piston system as the KN-3, but uses either an electric motor to do the pumping, or can be converted to manual-mode, in case you lose your electricity or end up needing to boost gas in Siberia. These are rugged and reliable pumps, and about a dozen have made their way to the shores of the United States. The KN-4 has been the subject of a re-work project, using 120 volt motors (the originals are 220, 3-phase), and also using synthetic piston seals to replace the leather originals. Leather works fine, and is used in the original German pumps as well, but when run at speed by an electric motor, requires near-constant lubrication with a mixture of water and glycerin. The synthetic seals run without lubrication and are a real improvement.

Starting off simple, here's the KN-3. As can be seen, it's a simple 2-cylinder booster, manually operated, with simple inlet and outlet connections. In this photo the foam-rubber protectors have not even been removed from the gauge and inlet manifold. This one was sold before it even arrived from Russia, and I dragged it out for a photo and then sent it to it's new owner without even fully unwrapping it.

A detail view of the KN-3, once again the gauge is still wrapped in it's protective paper and foam. To use this device, first bolt it down to the deck (or dock!), and hire two burley Russians to pump. Seriously, these work great and the effort is not too great for any diver in good enough physical condition to safely dive. Hey, it beats jogging!

Now, moving on the the heavy-metal: Here's a typical example of Russian craftsmanship at it's finest. This is the depot-level storage system, a lattice-work box made from whatever inferior grade wood can be found in Russia, sitting all dusty and foul on my garage floor. Notice the rusty nails and jagged edges of the sheet-metal straps that hold the whole mess together. Imagine getting a dozen of these dumped in your driveway by an surly truck-driver. Thankfully, I have a vicious dog that growled enough that the driver thought twice before getting too obnoxious about unloading these boxes.

Applying the special tool, better known as a crowbar, to the box, we find that inside that latticework is black tar-paper, just like used on the roof of a house, and inside that layer is the actual box containing the pump. The exterior paper and wood was to allow these to be stored in an open yard for years, not even needing to be stored in a warehouse. This is actually pretty typical of military packing systems. This one obviously was stored outside, as the outer box and paper was well, weathered. Guess what? The interior contents were perfectly preserved.

Here's the blue box, ready to be opened. This box is really just a lid that drops onto the heavy baseplate of the pump, and allows the pump to be protected when not in use, and allows it to be shipped with ease when taking the pump on an expedition.

Lifting up the box, we find the pump, a tool-kit, a spare-parts kit, and the books.

Here;s the pump-head. A little dusty, but in perfect condition.

Here's the motor. This is a 220 volt, 3-phase motor, so if you have 3-phase, great. Otherwise you can buy a cheap phase converter and run it off of 220 single phase (plug it into your dryer outlet), or just swap out the motor for a 120 volt one. It turns out that the motor shaft is the same as US motors, so a visit to the Granger catalog has furnished motors for a few guys who have converted them.

The piston seals are leather (unless modified, as mentioned earlier), and these lubricators drip a mixture of glycerin and water on the piston rods to keep them wet while pumping.

This is the outlet manifold, with gauge (in BAR, naturally). The manifold has two outlets, in the standard European oxygen thread. I made up adapters to 1/4 NPT to connect normal US spec hoses.

The inlet manifold has 4 inlets, so oxygen cylinders can be connected for cascading, and then for final boosting. This makes the pump into a cascade manifold as well as a booster pump, saving a load of time when boosting a large amount of gas.

Here's the tag on the pump. Here's the rough translation:

To avoid explosion follow these rules!

1. Before work wash hands with soap!

2. Lubrication of compressor should only be done with instruction!

3. Categorically use of oil is prohibited!

Probably good advice for all 02 pumps.

Here's the back of the pump. The shaft that is sticking out of the back can have a clever arm attached, and then with the connecting rod to the gearbox removed, the pump can be run manually just like the KN-3 (which has the same identical cylinders installed). For remote area operations, the motor can be removed completely, making the balance of the pump transportable.

Here is the spare parts kit, spilled out of it's envelope. Each of the little paper-wrapped envelopes contains a selection of spares.

Here is the tool-kit, enough tools to service and tear-apart the entire machine. The can is for carrying the glycerin mixture for lubrication.

Here's the manual, the Cyrillic "KH-4" transliterates to "KN-4" in the Arabic alphabet. It's funny that the Russians use Cyrillic, we use Arabic, and the Arabs use chicken-scratch for their alphabets. Go figure that out and let me know when you have it all sorted.

The "Passport" shows a date of manufacture of 1974.

The manual is in Russian (duh), but the drawings are excellent and are all you need to work on the system.

And here it is, sitting on top of it's storage box in my garage. The supply cylinders and big old Farallon scooter give it scale. This is the core of the gas-mixing system here, and is an essential part of the kit.

		Starting off simple, here's the KN-3. As can be seen, it's a simple 2-cylinder booster, manually operated, with simple inlet and outlet connections. In this photo the foam-rubber protectors have not even been removed from the gauge and inlet manifold. This one was sold before it even arrived from Russia, and I dragged it out for a photo and then sent it to it's new owner without even fully unwrapping it.
		A detail view of the KN-3, once again the gauge is still wrapped in it's protective paper and foam. To use this device, first bolt it down to the deck (or dock!), and hire two burley Russians to pump. Seriously, these work great and the effort is not too great for any diver in good enough physical condition to safely dive. Hey, it beats jogging!
		Now, moving on the the heavy-metal: Here's a typical example of Russian craftsmanship at it's finest. This is the depot-level storage system, a lattice-work box made from whatever inferior grade wood can be found in Russia, sitting all dusty and foul on my garage floor. Notice the rusty nails and jagged edges of the sheet-metal straps that hold the whole mess together. Imagine getting a dozen of these dumped in your driveway by an surly truck-driver. Thankfully, I have a vicious dog that growled enough that the driver thought twice before getting too obnoxious about unloading these boxes.
		Applying the special tool, better known as a crowbar, to the box, we find that inside that latticework is black tar-paper, just like used on the roof of a house, and inside that layer is the actual box containing the pump. The exterior paper and wood was to allow these to be stored in an open yard for years, not even needing to be stored in a warehouse. This is actually pretty typical of military packing systems. This one obviously was stored outside, as the outer box and paper was well, weathered. Guess what? The interior contents were perfectly preserved.
		Here's the blue box, ready to be opened. This box is really just a lid that drops onto the heavy baseplate of the pump, and allows the pump to be protected when not in use, and allows it to be shipped with ease when taking the pump on an expedition.
		Lifting up the box, we find the pump, a tool-kit, a spare-parts kit, and the books.
		Here;s the pump-head. A little dusty, but in perfect condition.
		Here's the motor. This is a 220 volt, 3-phase motor, so if you have 3-phase, great. Otherwise you can buy a cheap phase converter and run it off of 220 single phase (plug it into your dryer outlet), or just swap out the motor for a 120 volt one. It turns out that the motor shaft is the same as US motors, so a visit to the Granger catalog has furnished motors for a few guys who have converted them.
		The piston seals are leather (unless modified, as mentioned earlier), and these lubricators drip a mixture of glycerin and water on the piston rods to keep them wet while pumping.
		This is the outlet manifold, with gauge (in BAR, naturally). The manifold has two outlets, in the standard European oxygen thread. I made up adapters to 1/4 NPT to connect normal US spec hoses.
		The inlet manifold has 4 inlets, so oxygen cylinders can be connected for cascading, and then for final boosting. This makes the pump into a cascade manifold as well as a booster pump, saving a load of time when boosting a large amount of gas.
		Here's the tag on the pump. Here's the rough translation: To avoid explosion follow these rules! 1. Before work wash hands with soap! 2. Lubrication of compressor should only be done with instruction! 3. Categorically use of oil is prohibited! Probably good advice for all 02 pumps.
		Here's the back of the pump. The shaft that is sticking out of the back can have a clever arm attached, and then with the connecting rod to the gearbox removed, the pump can be run manually just like the KN-3 (which has the same identical cylinders installed). For remote area operations, the motor can be removed completely, making the balance of the pump transportable.
		Here is the spare parts kit, spilled out of it's envelope. Each of the little paper-wrapped envelopes contains a selection of spares.
		Here is the tool-kit, enough tools to service and tear-apart the entire machine. The can is for carrying the glycerin mixture for lubrication.
		Here's the manual, the Cyrillic "KH-4" transliterates to "KN-4" in the Arabic alphabet. It's funny that the Russians use Cyrillic, we use Arabic, and the Arabs use chicken-scratch for their alphabets. Go figure that out and let me know when you have it all sorted.
		The "Passport" shows a date of manufacture of 1974.
		The manual is in Russian (duh), but the drawings are excellent and are all you need to work on the system.
		And here it is, sitting on top of it's storage box in my garage. The supply cylinders and big old Farallon scooter give it scale. This is the core of the gas-mixing system here, and is an essential part of the kit.