The History of Coolers as a Mechanical Seal support System
The cooling of mechanical seals and the environment that it operates in, are just as important as the mechanical seal’s design and selection. Normally, the mechanical seal with the cooler as part of the support system, is installed and inevitably the maintenance crew tend not to look at the cooler again. The mechanical seal will run until its first failure, it will be replaced and the equipment will be put back into operation. After this replacement the equipment will only run for a fraction of its previous runtime. In 95% of all failure of mechanical seals in the past, nobody bothered to look at the integrity of the coolers and/or the seal support systems. Quoted comments like, “The coolers got nothing to do with the mechanical seal and the pump”, “We think that the cooler will work for ever, and is maintenance free”, “There is just water going through the coolers, what can go wrong”, “It always worked why will it stop working”, “Your mechanical seal is not the same quality as the first one”, are everyday so called reasons for premature mechanical seal failure and so the assumed reason for failures are always, or most of the time not the cooler.
Tube & Shell Type Cooler
In the past, AESSEAL had good quality cooling water and lots of it, to use to make the water cooler operate as it was designed for. For the last 12 – 15 years the cooling water that we use, have deteriorated to a cooling medium, which mean that the water that for the coolers were designed for, specific gravity changed from 0.998 to 1,200 g/cm3, this mean that the water changed to “MUD”.
Conventional water coolers (tube and shell) did not receive the same attention in development. Where, AESSEAL on the other hand did pay attention with the development of mechanical seals and support systems. These coolers do not support the mechanical seal and environment, due to the blockage of the shell side using “MUD” as the cooling medium, this, in the end causes premature mechanical seal failure.
With the drive towards reliability improvement over the last 10 years, maintenance crew suddenly realised that blocked and non-functioning water coolers are a big contributor towards the drive to improve reliability and availability. This means that MTBF (meantime between failures), the measurement tool for reliability, is difficult to improve with such non-functioning mechanical seal support systems.
To conclude the background history, with the given of cooling medium as “MUD”, the conventional water cooler is not the way of cooling our mechanical seals anymore nor the appropriate environment we want for our mechanical seals to be reliable.
Shell side blockage with “MUD” as cooling medium
Cost of maintenance and operation
Having all these coolers installed, knowing what the effect it has on reliable mechanical seal and pump operation and with the available cooling medium, the maintenance cost to clean these coolers increases dramatically. The coolers are on a weekly schedule to be cleaned and exchange units are bought to help the maintenance crew to cope with ever growing blockage demand.
To operate these coolers require a lot of utilities such as water and electricity. Cooling down the cooling medium via the cooling tower system causes a lot of vaporization to atmosphere. These losses of steam into the atmosphere are never to be recovered and need to be bought from Rand Water to maintain the operational level of the cooling water system.
Cooling water system with Cooling Towers
Alternative Coolers
In 2009 AESSEAL started testing an air cooler which look like a heavy duty Massey- Ferguson radiator, with a CAPI ES 23. This resulted in the MTBF improvement from 6 months to an enormous 54 months. The decision was taken to upgrade the other 15 units to the same mechanical seal and cooler system. In 2012 AES COLD WELD in India build the first proto type “helical fin coil cooler”. AESSEAL needed to have a cooler developed, tested and approved by API, before the end-user will start with their MOC (management of change) process to upgrade all the other units. AESSEAL received two single ¾” helical fin coil coolers in June 2013 from India and immediately installed and tested them with very good results. In the meantime the UK team started to develop and test the Python double coil cooler with the same success. A double and single version of the Python coolers was released in November 2013.
Proto Type from India | Python double coil cooler
The Perfect Alternative
After the Python coolers became available, and the word got out to the Sasol Secunda Operations, the MOC was done and now an effective alternative cooler is available for the current tube and shell coolers.
The Python Double Cooler has its own stock commodity number with the Sasol Secunda Operations, which make the purchasing process easier. Currently 50 Python coolers were supplied to Sasol Secunda Operations, which 27 is currently in operation.
The ROI (return on investment) to install one of the Python double cooler in place of a water cooler is around 6 months.
Facts, benefits and information
The Python Cooler is a “ZERO CARBON FOOTPRINT” cooler; this in normal language means that, AESSEAL doesn’t have to chop a tree down to generate power to make it work. In other words, AESSEAL uses absolutely no utilities such as water and electricity.
The Python Cooler comes with a stand ready for retrofit installation. The complete unit with stand is all in 316 stainless steel and therefore maintenance free.
The coolers come with a complete data pack, consists of 3rd party approval, PED compliant, welding procedures, fine tube specifications, pressure test certificate, etc.
Product Reference
The following AESSEAL reference are available:
– LN-UK-COOLER-02PDF (AESSEAL Cooler Range Brochure)