About Us & the System

TDC Hydro Ltd and its trading company TDC Services have been established for over 25yrs and are based in the Deeside area of North Wales close to the English border and Chester. With its purpose built offices and workshop right alongside the A55 (European highway E22 which is the arterial route from Ireland to mainland Europe), it is well placed to serve industry in all locations. From this position we can quickly access industrial markets whether they be local or UK wide, with Ireland just a ferry journey away. Export markets are also easily accessible as we are close to two major airports and shipping ports.

TDC was originally formed to supply general and heavy industry with high-pressure cleaning equipment, to which we added floor cleaning and sweeping equipment for factories and very high powered jetting equipment for more specialised tasks such as paper cutting. Amongst other problem items that needed cleaning effectively came road tankers, IBC’s and drums within chemical plants and the oil and petroleum industry, so when we were tasked by Zeneca Pharmaceuticals to provide an improved method of cleaning reactor vessels our experience with these proved invaluable.

The Pharma industry is one of the most regulated industries in the world and Zeneca (now AstraZeneca) was one of the most highly regarded, so success in working with them would give us credence with other companies in this field, and this has proved to be the case.

The Problems that we were faced with in terms of reactor and associated plant cleaning will be all too familiar to plant operators, put simply – reactors do not seem to have been designed with cleaning in mind!

Plant operatives showed me where the main problem areas were, in general these were heavy deposits above the ‘tide line’ and on the underside of the ‘dome’ as well as surface staining on the walls and the agitator shaft and dip tubes etc.

The conventional cleaning methods used for process equipment involve multiple solvent charges, refluxes and transfers (referred to in some industries as ‘boil-outs’). And in the case of vessels that have no heating facilities and/or no agitation, methods extend to repeated flooding with solvent.

Plant managers were talking of up to six weeks for a single vessel to be cleaned sufficiently to be put back into service, and it is generally found that numerous refluxes are required.

The theory of a reflux is that the boiling liquid will create vapours that will rise and deposit themselves onto the surfaces above the liquid level, and in turn this interaction will loosen and remove the deposits. This methodology relies on dissolving the soil - a factor that depends on wetting, solubility characteristics, temperature and agitation. In conventional process equipment cleaning with solvents, such characteristics are very variable and are sometimes extremely compromised.
 
These methods are not necessarily efficient in the use of solvent or rinse water, and are also variable in their effectiveness and repeatability.

Even with reactors that are fitted with CIP Systems experience has shown that this soil could not easily be dislodged by the low pressure water or solvent jets created by the spray balls as they are not directional.

As a result of this physical entry and manual cleaning of the equipment was often required.

TDC’s experience indicated that energy was needed to impact this soil off the surfaces and therefore the way forward was High-Pressure Water with equipment that provided directional jets, but as it was relatively new approach it had to be seen to be safe and easy to use.

By using high-pressure water to impact the soiling from the surfaces, it would mean that the product was no longer required to be soluble in the wash liquid and did not need to be immersed in it, therefore the quantities required would be greatly reduced.

The key was to position the water jet nozzles within the reactor so that they eliminated the “shadows” that occur when things like stirrer shafts get in the way.

The system developed by TDC that enables this, is to insert an Automatic Cleaning Head (our “RoboHead”) into the vessel via the manway using an adapter plate and specially designed positioning device. The head is then placed first of all to one side of the agitator, and the system run for a short period of time, the head is then repositioned to the other side of the agitator to eliminate any shadow effect.

Dependent on the design of the vessel this repositioning may need to be repeated a second time, but normally two positions and a run time of 20 minutes for each is sufficient giving a total cleaning time of 40 minutes.

The length of running time that is required (and therefore water quantity) is dependant on vessel size, the larger the vessel the longer the running time and conversely the smaller the vessel the shorter the time, this is because the jets index as they operate and the greater the distance they need to travel the longer the running time required to close the gaps. But as an illustration a 12,000 Lt vessel would take about 40 mins and as the water feed rate is usually in the order of 22 Lpm a quick calculation will show you that the quantity of water being used is less than 900Lts. This is a dramatic reduction on the quantities that the traditional method uses.

After this cleaning cycle all of the gross contamination will have been removed, visual inspection and just one solvent reflux would normally be all that is necessary, and this is repeatable and reproducable.

The successful cleaning operation is carried out in a fraction of the time taken by traditional methods which means that product changes can be accomplished quickly – no more need for long campaigns – and plants can truly be used as “Multi-Purpose Plants”.

Please note that water alone does not always provide an acceptable clean, there are certain products that require extra encouragement! This may take the form of acid in concentrate or detergents such as Steris’s CIP100 or 200, and for the application of these we have developed a chemical induction system that allows the injection of these chemicals through our RoboHead to fully coat the vessels internal surfaces without risk to the operator or the need to change nozzles or equipment, as the complete operation is carried out with the RoboHead in situ.

The resulting system of cleaning we term as “HydroDynamic Cleaning” and to date most of the leading players in the market have adopted it for their plants (see the running banner on our home page) and as proof of its success as a quick and easy method to remove gross contamination, most customers have gone on to purchase numerous sets of equipment.

The one great advantage that we have is that we can bring our equipment to site and conduct a trial to prove that it works on your reactors and associated pipework etc. (our equipment can be used to clean many other items of plant) so we have gained a great deal of experience with the numerous trials and contract cleans that we have carried out, and are therefore able to help advise on plant modifications and cleaning procedures.

The Pharma industry has of course its own peculiarities but it is similar to the gas & petroleum industries in that they too have to cope with potentially explosive atmospheres, so any equipment supplied or installed has to meet exacting standards, including the latest European Directive 99/92/EC (also known as ‘ATEX 137’ or the 'ATEX Workplace Directive’) places minimum requirements for improving the health and safety protection of workers potentially at risk from explosive atmospheres (ATEX is taken from the French "ATmosphère EXplosible").

TDC has many years of experience with this type of equipment so to ensure compliance with this Directive all of our high-pressure pump units come with full ATEX Type Certification from SIRA Certification, a leading Notified Body (Certificate No: SIRA04ATEX6228) and we believe that TDC are unique in this respect with the only fully ATEX Compliant high-pressure pump unit with all stainless steel. These units and all the compliant accessories are exclusive to TDC with most covered by design rights.

As a successful and prominent player in this marketplace TDC Hydro stands well placed to move forward inline with the every increasing regulation and requirement for compliance as a company that works regularly within the most highly regulated industries in this country and abroad, so customer satisfaction is guaranteed.