Magnetic Attraction!!

Two of our main product ranges that we supply in the UK market greatly benefit from the use of powerful earth magnetic technology.


Autoclave Engineers first developed and launched their magnedrive powered laboratory stirred reactors back in 1958 leading the world in this development. This was a way of having a sealed reactor free from risk of leakage or contamination that could be accurately stirred even when run at high pressures. This was achieved using a magnet coupling between driver magnets (rotated by an motor) and an encapsulated inner magnet assembly which leads to a shaft and impeller, so as the driver magnets are rotated the impeller and shaft are also rotated. Such are the strength of the magnets used that accurate controlled stirring can be achieved even at high torque requirements and under high pressures or temperatures.

The other excellent use of magnets comes from Rubotherm. Many years ago the research team in the Thermodynamics dept at the Ruhr University in Bochum had a project requiring gravimetric analysis of samples at raised pressures. Conventional gravimetric systems have a direct connection between the precision balance and the sample - which is great for low pressure applications, but once you get above 20bar or so or start to look into things like corrosive vapours then you get a bit stuck as your balance is in the same area as the sample you wish to subject to the high pressure etc, and doing so will damage the balance, so conventional systems weren't any use.

So using a magnet/electromagnet coupling, a position sensor and a cracking control system they devised a magnetical coupling gravimetric system for measuring mass change/transfer of sample while subjected to a wide range of conditions.

This technology was eventually patented and a spin off company formed (Rubotherm). Systems have now been supplied all over the world for a variety of applications, including gas storage (e.g. hydrogen, CO2 or Methane into zeolites or MOFs), corrosion testing, biomass and coal gasification, polymer degradation and lots more. We've been up to pressures as high as 2000bar, temperatures as high as 1600degC and no problem at all dosing corrosive things over samples and measuring mass change.

The latest development allows TGA type measurements at raised pressures. Why would you want to do that? Well with some applications it allows you to imitate the real life conditions that would effect your sample and measure accurately what happens, for example HP TGA on oil, biomass or coal gasification, degradation of materials used in off shore drilling..... This hasn't been possible until now as other TGA systems only operate at atmospheric pressures.

So thanks to the attraction of the magnet our customers in the UK are able to push their research into new and exciting areas......

Plumber's tape?

If you google Teflon Tape the very first result is the wikipedia page that describes Teflon tape as

"Thread seal tape — commonly known as "Teflon tape", "PTFE tape", "tape dope", or "plumber's tape" — is a polytetrafluoroethylene (PTFE) film cut to specified widths for use in sealing pipe threads. The tape is wrapped around the exposed threads of a pipe before it is screwed into place. Since the PTFE is malleable, deformable and impermeable, it acts a little like putty under compression, being forced into small gaps between threads in order to create an air- and watertight seal when threaded into a joint. The tape is commonly used commercially in pressurized water systems, such as central heating systems, as well as in air compression equipment and thread joints with coarse threads."

And then futher on in the same chapter

"Over-use, or mis-application of thread tape may be a hazard. As the tape material is so soft, excess or overhangs may easily break off and form a foreign body contaminant that could jam a valve seat etc.

Thread sealing tape is almost entirely applied by hand, owing to the ad hoc nature of most repair work"

Teflon also has a melting point of around 327degC, but its properties degrade above 260degC according to DuPont (the manufacturers of teflon).



We get asked about this a lot, so let me explain, the Autoclave Engineers range of reactors that we supply in the UK (see our Merrow Scientific reactor page) use a Metal to Metal engineered sealing for all of their valves, fittings and tubing, so no teflon tape.

The benefits of this method include:

• Precise, repeatable and highly rated sealing
• All parts are serial numbered so you can easily swap or replace
• High temperatures and extremely high pressures are no problem
• No welding (which could potentially have weak points which could lead to failure under pressure and are permanent and not easily replaced or repaired)
• And no plumber's tape......

British project aims to use energy from coal to produce clean electricity

British project aims to use energy from coal to produce clean electricity

Very interesting article looking at a recent development in commercial coal gasification in the UK and using the syngas produced to generate energy either using the hydrogen in fuel cells or a process like the Fischer Tropsch (FT) process to turn the syngas into a synthetic petroleum substitute.

Coal and biomass gasification are things we and our suppliers at Rubotherm are actively involved in on a research scale. Using the Rubotherm MSB or HP TGA these gasification processes can be carried out at high temperatures and raised pressures to get an understanding of the process and product produced.

FT research is something Merrow Scientific are also actively involved in in the UK market with our fixed bed and slurry reactors from Autoclave Engineers. Mainly carried out in oven based environments this custom configured systems allow users to carry out exact research on a small scale to develop alternative fuel sources.

Holiday season? More like conference season!!

August is traditionally a holiday month all over the world, with many companies (particularly those in Southern Europe) traditionally closing for the entire month. However this year we're finding that August (and also September) has become the month of conferences.

Last week Merrow Scientific was present at a very well attended 42nd IUPAC congress in Glasgow.

Good to see such an active community on various topics including one close to our hearts, hydrogen storage. So our Rubotherm gravimetric sorption systems went down well. As well as several further enquiries for the new unique high pressure TGA system based around the Rubotherm MSB (magnetic suspension balance) technology - including coal and biomass gasification.

And next week it's on to the British Zeolite Association annual conference, again lots of focus on unique storage materials for such applications as hydrogen storage. Good to see lots of effort being pushed into the new fuel sector.

And then the following month it's on to the RAPS (Polymer Science) meeting and the Surface Area, Pore Size and Related Measurements meeting at Imperial College......

So a busy month ahead at conferences rather than holidays, but given the state of the weather.......