T: +44(0)1625 665 999 F: +44(0)1625 665 998
2012-08-30 14:18:02
Kek-Gardner Ltd is pleased to announce the appointment of Neale Monks as Systems Sales Manager. The position has been created in response to increasing business and as part of a planned strengthening of the company’s Systems Division.
Neale is well known in the Powder Processing Industry and has many years experience from design engineering to technical sales and on site commissioning, providing him with hands on experience in the design of bespoke systems and solving powder processing requirements. Neale returns to the company after 5 years away and brings back with him a ready knowledge of Kek-Gardner Ltd.
Managing Director George Tunnicliffe said: “We are delighted that Neale is joining us to help with the next stage of our company development. His wide experience and knowledge of Kek-Gardner’s customers and markets will be a great asset as we seek to expand our Systems activities.
Neale said: “I am looking forward to making a strong contribution to a company well established in the Powder Processing Industry and to working with the committed team at Kek Gardner to focus on the needs of their customers”.
For more information on Kek-Gardner and its products call +44 (0) 1625 665999,
Email sales@kekgardner.com or visit www.kekgardner.com
2012-07-25 13:17:22
A new milestone has arrived for Kek-Gardner Ltd as it celebrates its 3rd anniversary this year and continues to go from strength to strength. Managing Director George Tunnicliffe who founded the company along with a highly experienced management team acknowledged that the progress the company has made over the last three years has been a reflection of the hard work and dedication of the staff. The majority of Kek-Gardner's growing number of employees has many years of extensive hands on experience in the Powder Processing and Handling Industry. Since its formation, the company has also added to the team by introducing an apprenticeship scheme to both enhance the skills of its employees and to give young people in the local area the opportunity to gain valuable training and experience for a long term structured career path. Kek-Gardner's key objective is to supply solutions based equipment and systems to meet the needs of the Food, Pharmaceutical and Chemical industries. It combines excellent process knowledge with the technology to deliver a complete materials handling package from Technical Sales support through to Site Acceptance Testing and handover. Managing Director George Tunnicliffe commented, “I think the milestone is cause for celebration and am delighted at our progress to date. We have reinforced relationships with our key customers and alliances and we intend to continue to focus the business and achieve growth in our target markets.” For more information on Kek-Gardner or its products call +44 (0) 1625 665 999, email sales@kekgardner.com or visit www.kekgardner.com
2012-04-17 11:03:30
Since its launch in 2004, Orchard Valley Foods (OVF) has gone from strength to strength, turning over £9.5 million in sales in 2010-11. The food ingredients specialist based in Tenbury Wells, Worcestershire supplies a wide range of food ingredients for a variety of applications including confectionary, bakery, ice cream, flavoured coatings, beverages and breakfast cereals.
They pride themselves on flexibility and attention to detail, which was exactly what Managing Director Mike Forrester needed when specifying a new mixer and sifter for the company's blending and packing operation. The equipment needed to be flexible enough to accommodate a variety of different recipes and ingredients whist maintaining OVF's exacting standards. Having dealt with Kek-Gardner in the past, he had no hesitation in contacting them again for his new equipment. As Mike comments “We are committed to meeting our customers' requirements and Kek-Gardner were happy to discuss the process and work around what we needed".
Trials at Kek-Gardner’s technology centre confirmed that the equipment would meet the requirements both in terms of flexibility, throughput and product quality. As a result a Gardner 1500 litre Plough Mixer and a Kek K650C Centrifugal Sifter were installed at Orchard Valley Foods.
The equipment is part of the blending and packing operation, which processes cake mixes, flavoured icings and sugars. Initially, the dry ingredients are transferred from a sack tip unit to the K650C sifter for policing before being dropped into the 1500 litre mixer. Block fat is added and mixed in half tonne batches before being discharged into big bags and transferred to the packing line.
The process itself is relatively simple but is the equipment's flexibility that makes it special. The mixer needs to be flexible enough to accommodate a number of different ingredients for the variety of recipes that OVF's customers demand. Bakery ingredients can have differing characteristics from fine to large, coarse or fragile particles all of which had to be accommodated in one machine. The answer is a multi-purpose mixer with variable speed drive, with easy access to the internals to allow cleaning between batches.
The blending and packing line has been in operation and running for 12 months and Mike has no regrets. The process has been running problem free, which is primarily thanks to the expertise of Kek-Gardner’s installation team. As Mike comments ‘The commissioning was excellent. The commissioning team was very professional and made sure everything ran smoothly’.
The full scope of Kek-Gardner’s products can be seen on their web site at www.kekgardner.com. Alternatively, to discuss a specific application, contact them on +44 (0) 1625 665999.
2011-08-03 14:47:12
Kek- Gardner Ltd is committed to developing its workforce and has introduced an apprenticeship scheme to both enhance the skills of its employees and to give young people in the local area the opportunity to gain valuable training and experience for a long term structured career path.
In recent months, Kek-Gardner has recruited three new apprentices who are studying at local colleges; Tom Booth is studying Engineering and joins the company as an apprentice Applications and Assembly Engineer. Nicole Bradley, already with a Business Administration NVQ joins as Purchasing Assistant and is due to start a Purchasing course in September. Rebecca Turner joins the Accounts Department and is studying for the AAT (Association for Accounting Technicians) Qualification.
Kek-Gardner's MD, George Tunnicliffe is convinced that this form of recruitment and vocational training helps both the company and the trainees alike and comments "Hiring apprentices is a tried and tested way of investing in the future of Kek-Gardner at the same time as giving our staff the practical skills and academic qualifications they will need for a successful career... The mixture of on and off the job training ensures they learn the skills that work best for our company"
For more information on Kek-Gardner or its products call +44 (0) 1625 665 999, email sales@kekgardner.com or visit www.kekgardner.com.
2011-05-18 14:15:13
Pharmaceutical manufacturers are constantly striving to meet the increased demands of today's rapidly changing healthcare environment and meet customer requirements at the same time. Almac Pharma Services are no exception. Established in 2001, Almac, is a Contract Development and Manufacturing service provider to the Pharmaceutical and Biotechnology industries with over 30 years expertise in the development and manufacture of solid, oral dose products. Innovation, quality and customer service are at the forefront of the company’s philosophy.
With market expansion throughout Europe for one of their client’s key lead sachet products, Geoff Sloan, VP Manufacturing Operations at Almac Pharma Services needed a solution to meet the five fold demand increase "We simply could not meet demand. The only option was to expand our commercial facilities".
Almac Pharma Services, with their client partner, invested £2 million adding a new dedicated 5,500ft2 facility. With an aggressive timeline, the facility was built, equipment sourced and fully validated within nine months. The new facility incorporates dispensing and blending suites to accommodate 2.5 tonne batches along with sachet filling and packaging lines for processing up to 120 million sachets per annum.
With a User Requirement Specification (URS) to detail critical requirements coupled with a strong Almac Pharma Services' existing relationship with both the Kek-Gardner team and their Irish Distributor meant that Geoff Sloan had no hesitation in approaching the company when he had an engineering requirement for the new Blending Suite. Almac Pharma Services already have Kek Sifters, Kek Cone Mills and a Gardner Blending System at the Craigavon site and were pleased with the equipments’ performance. As Geoff Sloan commented “We are committed to meeting our customer’s requirements and Kek-Gardner were happy to discuss the process. Together we developed the right solution to meet the specifications and the project deadline”.
Almac Pharma Services concluded that the process would be more efficient and cost effective if a large blender was used to meet the increased production capacity whilst ensuring the accuracy of the finished drug product. Trials at Kek-Gardner’s technology centre confirmed that the equipment would meet the stringent cGMP standards as detailed in the URS both in terms of throughput and product quality. As a result a blending suite comprising a Gardner 4200 litre working capacity Double Cone Blender, a Gardner 700 litre working capacity Y Cone Blender and a Kek K650CV inline Vacuum Centrifugal Sifter, tied together by lean phase pneumatic conveying was installed at Almac Pharma Services.
The process begins with a premix of salts and the active pharmaceutical bulk material, which is initially sifted in the K650CV Sifter and transferred to the 700 litre working capacity Y Cone Blender for preliminary blending. The pre mixed material is then conveyed to the 4200 litre Double cone Blender where it is blended along with the rest of the active pharmaceutical bulk material. The material is then discharged into a Matcon bin and transferred to the Mediseal LA 500 / P1600 packing line for processing into finished sachets.
GARDNER Blenders are part of a comprehensive range of mixing equipment supplied by Kek-Gardner, which also includes Plough and Ribbon Mixers. In addition, Kek-Gardner also supplies the full range of Size Reduction Mills, Air Classifier Mills and Centrifugal Sifters.
Kek-Gardner’s intimate knowledge of the pharmaceutical industry enables them to produce bespoke equipment to meet the demands of the major pharmaceutical companies and their regulatory authorities and are prepared to work with each customer to offer a process solution to any application requirement.
The full scope of Kek-Gardner’s products can be seen on their web site at www.kekgardner.com. Alternatively, to discuss a specific application, contact them on +44 (0) 1625 665999.
Almac Pharma Services is an FDA approved global outsourcing partner with over 30 years' experience in the development and manufacture of solid oral dose products. Their capabilities include: formulation and analytical development, clinical and commercial-scale drug manufacture, primary and secondary packaging and labelling, EU import testing, QP release and global supply chain management to end-users.
2011-03-09 16:49:58
The installation of a Kek Universal Milling Package has made such a difference to a leading UK food manufacturer that the payback period will be less than two years.
The company needed a replacement for an existing mild steel installation that was over 20 years old and wholly inefficient. Leaks in the process created problems of both dust and waste, which meant they were losing an estimated 4 – 6kg of product per day. The Health & Safety issues also needed to be addressed, as the process was noisy, dusty and had manual handling issues. They wanted to upgrade the system to a modern, clean and efficient process.
They already had a Kek mill and sifter as part of the original system, so were familiar with Kek-Gardner’s products. After viewing the website and subsequent conversations with process engineers, the Production Supervisor was confident that Kek-Gardner had the right capabilities. “They have a good reputation and understood the process and what we needed to achieve. We also had a short lead time that they were able to meet”.
During the process, the raw product is conveyed into a collection hopper, which feeds the 4H Kek Universal Mill at the heart of the milling system and is conveyed to an intermediate storage hopper. The material is dropped into a Double Cone Blender to complete a blending cycle and is then conveyed to storage bins. Salt is an integral ingredient and, due to its corrosive nature, all materials are manufactured in stainless steel.
The Kek mill produces a finer powder than the previous mill. As a result, the required blend consistency can be achieved in a much shorter time, which has reduced blending times considerably.
The dust-tight installation is cleaner, more efficient, creates less noise and there is now 100% recovery of product.
The company’s Production Supervisor is delighted with the results that the new mill has generated; “Previously, we only managed one blend in an eight hour shift. Now we get three blends per shift, with no mess and no waste…we couldn’t be happier”.
Kek Universal Mills are part of a comprehensive range of milling equipment supplied by Kek-Gardner, which also includes Kibbler mills, Cone mills and PPS Air Classifier Mills. In addition, Kek-Gardner also supplies the full range of Mixers, Blenders and Centrifugal Sifters.
2012-07-24 10:45:53
Kek-Gardner Ltd will exhibit at POWTECH 2013, Nurnberg, Germany 23rd - 25th April 2013
2010-10-06 14:52:29
Case Study 1: The multi product contained mill system
The requirement for this mill system was to provide a contained size reduction process, flexible enough to handle multiple pharmaceutical products yet mobile enough to be re-sited within several clean locations. The key to meeting these challenges was to design for the most arduous material, and then build in variability within the process settings to accommodate the lesser demands. Of course, all this had to be packaged into a design which could allow quick and simple re-positioning of the whole unit.
Given the ergonomic complexity of the system within a glovebox, a full-scale mock up was built and demonstrated to the end user prior to the manufacturing stage. Not only did this ensure a workable design, it served to familiarize the operators with the system at an early stage. The result was a nitrogen inerted impact mill system within a glovebox with the following processing criteria:
Case Study 2: Rapid response Air Classifier Mill system
Experiencing a spike in demand and recognizing the high value for powder paints in smaller capacities, a leading manufacturer in the Powder Paint and coatings industry needed a new small batch production system which could accommodate quick product change over requirements. Following the manufacturers specified criteria, an integral compact designed Air Classifier Mill was proposed to fit within the specified footprint and meet throughput capacities while efficiently producing powder paints.
2010-10-06 10:34:50
You may recognise The New McCowans (Scotland) Ltd’s flagship brands of Wham bars and Highland Toffee and if you’ve ever purchased own brand sweets from any UK supermarket, the chances are that you’ve bought a New McCowans product. With a history dating back 160 years as one of Scotland’s leading independent manufacturers of traditional sweets and confectionery, New McCowans (Scotland) Ltd know a thing or two about sweeties and are passionate about the quality of their products. When New McCowans needed a new sugar mill for their manufacturing plant in Stenhousemuir, near Falkirk, they had no hesitation in approaching Kek-Gardner. A KEK Universal mill had been running problem free at their Edinburgh site for 20 years with only one bearing change needed during all that time so they were confident about Kek-Gardner’s capabilities and expertise in the field of sugar milling. On site production space is at a premium and this was a major consideration for Engineering Manager, Ian Love, when he needed to boost the production of sugar for one of their boiled sweet lines. The space restriction was a key requirement in defining the mill’s layout and specification to ensure a trouble free installation. Traditional milling system designs have a filtered air intake at the material feed point. Air acts as the 'carrier' for the product through the mill and as a result has to be filtered out of the system at the milled product collection point. The filter required to separate milled product from the air can be very costly and the size of the filter unit can cause significant problems where space is at a premium. The explosion risk associated with finely divided powders entrained in an air stream was an additional complication. Faced with these challenges, Kek-Gardner proposed a 10 bar rated 3H KEK Universal Mill, based on a closed loop re-circulation system. Once closed up, and ready to run, no additional air is introduced into the loop and therefore there's no requirement to remove it after milling. The air carrying the product is continually re-circulated back to the mill inlet. Using this approach at New McCowans (Scotland) Ltd made it possible to eliminate the need for bulky and expensive air filtration and explosion venting - offering a cost effective, quiet running mill at the same time. Mr Love was pleased by the way that Kek-Gardner had tailored their proposal to cope with his requirements. They gave him the confidence that they could do the job and demonstrated their ability to meet the process specification through trials in their Technology Centre in Macclesfield. The mill has been running for almost six months, 24 hours a day, five days a week and Mr Love is delighted with its performance both in terms of production volume and efficiency. “There were three reasons I’m glad I went with Kek-Gardner” he says, “Firstly, I like to buy British. Secondly, the price was competitive compared with another supplier we looked at and thirdly, Kek-Gardner’s technical expertise and support was on hand throughout the job…they know what they’re doing!”
2010-10-06 10:36:17
Most powders, to a greater or lesser degree, have the potential to ignite during processing and this risk must be accommodated to ensure the safety of operatives and their surroundings. Kek-Gardner Cantilever design Centrifugal sifters are type certified as ATEX compliant to Zone 20 internally i.e. where there is a continuous presence of combustible dust. In simple terms, all cantilevered sifters in the range are designed and manufactured to be inherently safe, thus, effectively eliminating the risk of ignition inside the sifter. Not only does this give peace of mind to the user, it avoids the alternative costly measures such as vented, inerted or 10 bar PSR designs. The Cantilever design Kek Centrifugal Sifter is arguably the best in the industry. It provides users with higher standards of hygiene and ease of operation and can be used on a variety of applications including classifying, policing and de-dusting.
2010-10-06 10:36:50
Kek-Gardner Ltd is proud of its comprehensive range of KEK cantilevered centrifugal sifters from the Laboratory sifter for lab work and R & D purposes to the K800C, capable of throughputs of up to 40 tonnes per hour. Now, as a result of growing demand for a higher throughput cantilevered design sifter, the Model K1100C is launched. The K1100C is the largest cantilevered model sifter in the KEK range, capable of throughputs of up to 70 tonnes per hour The Cantilever design Kek Centrifugal Sifter is arguably the best in the industry. It provides users with higher standards of hygiene and ease of operation and can be used on a variety of applications including classifying, policing and de-dusting. This extension to the range offers customers high capacity sieving with the added benefits offered by the cantilevered design i.e. reduced downtime for cleaning and maintenance. The first K1100C units have already been ordered and will be despatched later this month. The new model is also available for inline and pressured applications.
2010-07-13 10:31:19
It has been the demands of Kek-Gardner’s customers in the Pharmaceutical Industry that have been a major driving force behind the development of Kek-Gardner’s range of size reduction mills, centrifugal sifters and mixing equipment. They have an impressive track record of supplying processing equipment to major Blue Chip companies including Pfizer, Takeda, Abbott Laboratories and are a preferred supplier to GSK.
Kek-Gardner’s intimate knowledge of the pharmaceutical industry gives them the expertise and capability to meets the demands of the major pharmaceutical companies and their regulatory authorities. This may be a standard, stand-alone unit machine for an uncomplicated application or a custom built system for individual process applications. Kek-Gardner can supply the complete package from design and manufacture to installation and commissioning of the complete system, including the associated pneumatic (or other) conveying systems, support structures and controls.
Applications
Kek-Gardner works with each customer to offer a process solution to any application requirement e.g. Kek-Gardner are among the pioneers in low temperature size reduction systems where processing temperature is kept low enough to prevent softening or degradation of the feedstock using liquid nitrogen.
Materials that have the potential to ignite during processing must be accommodated in the equipment design. As well as the traditional vented systems, Kek-Gardner specialise in Inerted and 10 bar PSR designs.
With the ever-increasing toxicity levels of active ingredients, the need to protect operators from hazardous materials becomes more critical. At Kek-Gardner, equipment is designed to provide the highest levels of primary containment and protection within our core equipment e.g. Glove boxes are used in high containment applications and also offer CIP capabilities and other features such as remote drive through glove box with motor in non-isolated (grey) area.
2010-10-06 10:35:47
2010-06-09 11:09:41
With the trend towards pharmaceutical products of higher toxicity requiring greater standards of containment, the protection of mill systems against the consequences of a powder explosion are of ever greater importance. The selection of explosion protection method is often made at a late stage in the mill system design when many other parameters have already been fixed, however the method of protecting the system from an explosion can be highly interactive with other process requirements. In order to achieve an optimum overall design for the system it is therefore necessary to have a good understanding of the relative merits of the various methods of explosion protection and to consider these at in early stage in the design process. The purpose of this paper is to examine practical, cost effective solutions to a variety of mill applications where the need is to provide total protection against the risk of a powder explosion whilst maintaining effective operational control over product emissions.
Why Containment? The surge in demand for containment in the pharmaceutical industry, and indeed in other industries, is a direct reflection of the increased potency of modern drugs and the demands of ever more stringent legislation. This has challenged the pharmaceutical companies and, in turn, their equipment manufacturers to meet the criteria. Here we consider the implications for manufacturers of size reduction equipment where impact, air flow, temperature, high speed rotating components, bearings and seals are all design considerations in addition to the hazards of the product being processed. What are the issues? As pharmaceutical compounds become more potent, acceptable Operator Exposure Levels (OEL’s) are reduced. The trend towards finer Particle Size Distributions (PSD's) makes effective containment more difficult. Finer PSD’s also make products more of an explosion risk. In addition, legislation is getting tougher - the ATEX regulations came into effect on 1st July 2003 in the European Union. Despite all this, there are still the commercial pressures to ensure that equipment costs are kept under control whilst meeting these higher standards. Factors Influencing the Containment Solution The key factors influencing the containment solution for any process includes; the toxicity and associated OEL level’s of the materials to be handled, their PSD's both before and after processing, the pressure at which the process takes place, any change in product characteristics after processing and the explosion risk characteristics of the product. Milling systems pose all of these problems and particularly at the system end points i.e. the material in-feed and discharge points and also at the mill’s air/gas intake & exhaust vent. Handling Potentially Explosive Products The provision of explosion protection for a milling operation can significantly add to the costs, size & complexity of the system. Poor selection of explosion protection method will waste money and compromise the system’s operational efficiency. It is important to have a good understanding of the relative merits of explosion protection methods in relation to the process requirements. The four recognised methods of dealing with the explosion risk in a milling system are: Venting, Suppression, Inerting and Containment. Venting is clearly not an option when dealing with potent, toxic or otherwise hazardous products. The last thing you want to do is to spread such materials far and wide aided and abetted by an explosive force! Although the principle of suppression does not compromise the containment requirements of a system, it is not widely used in the pharmaceutical industry. This is due mainly to the amount of clean up required in the system after a suppressant discharge and because it involves the introduction of materials that may be detrimental to the product which may have a considerably high value. Inerting Systems
Inerting systems use an inert gas such as nitrogen or argon to reduce the oxygen level to below the limit that will support combustion. Their main advantages are that they do completely eliminate the possibility of an explosion, the system can be sited anywhere and they are ideal for low Minimum Ignition Energy (MIE) materials. Disadvantages include increased system cost, ongoing cost of the inerting gas and the need to protect operatives against hazards such as asphyxiation or “cryo burns” if the gas is generated from liquid. Safe venting of the inert gas must also be catered for which may be problematic dependant upon site layout etc.
Containment Systems
Containment systems are constructed to contain the maximum pressure rise during an explosion. Such systems can be sited anywhere, they do not compromise the containment OEL's in the event of an explosion and there are negligible maintenance requirements. On the other hand, there is the higher initial cost of manufacture and explosions can take place which may not be suited for use with sensitive, low MIE materials
Are there alternative designs?
At Kek-Gardner we have asked ourselves, "Can we utilise the ‘best bits’ from the standard traditional methods? Can we produce compact mill designs to aid containment issues – e.g. Use gloveboxes? Does this need to incur additional expense?”
One solution is the Closed Loop Milling System. 
Closed loop systems can be based upon the containment principle. They are much more compact and cheaper than traditional containment designs. The mill process gas is re-circulated around the system which eliminates the need for filters, slam shut valves, etc. These systems offer easier cleaning with less chance of cross contamination.
Closed loop Mill systems have many advantages but they may still not be suitable if the product has a low MIE and is prone to dust explosions.
We need to consider a system to cater for this class of materials hence the development of the Inert/Closed Loop Hybrid System. This offers many of the advantages of the Closed Loop method, (compactness, clean-ability, etc.) with the additional advantages that the inert processing atmosphere enables its use with even the most sensitive materials. They do require the use of filtration, but because you are only venting ‘top up’ volumes of gas, these can be small “throw away” units. Also they do not require construction to withstand pressure shock containment.
Gloveboxes
For the ultimate in containment, milling systems can be enclosed in "gloveboxes". Closed Loop & Inerted Closed Loop systems are ideally suited for use within Gloveboxes.
Their compact design requires a smaller enclosure with fewer penetrations through the walls. Where required, the gas flow through the enclosure can be chilled to limit the temperature rise of the mill. Our experience confirms that system mock-ups benefiting from operator input at an early stage of the design process allow confirmation of the ergonomics. This saves potential costly rework of equipment and manufacturing delays.
Key Factors
2010-10-06 10:37:43
Kek Gardner has the answer : Closed-Loop Fine Grinding Mill
The initial decisions that are made when defining a mill system design are determined by the actual milling application. Primarily, the characteristics of the material to be milled i.e. product hardness and the required milled particle size determines the specification of the grinding media as well as the relative need for explosion protection. The throughput rate required affects the size of the mill that will most suitable. Having established the need to mill and determined the general mill type that is required, cost and space considerations are the next stage in defining a fine grinding mill’s specification, especially when aiming to boost production with limited space available. This often conflicts with the obligation to protect the mill system against the consequences of a powder explosion, particularly in the pharmaceutical industry where products of higher toxicity require the highest standards of containment. In a traditional, normally aspirated mill system, the provision of explosion protection can significantly add to the cost, size, clean-ability and complexity of the system.
The Problem
Traditional milling system designs have a filtered air intake at the material feed point. Air acts as the 'carrier' for the product through the mill and as a result has to be filtered out of the system at the milled product collection point. Given that, for example, a standard KEK Universal Mill is capable of generating an airflow of 530m3 /hr, it is easy to appreciate the size of the typical filter unit required to separate milled product from the air. This can be very costly and cause significant problems where space is tight. The explosion risk associated with finely divided powders entrained in an air stream is an additional complication. It is not always acceptable for product resulting from an explosion to be
vented to atmosphere.
This paper discusses the four recognised methods of dealing with the explosion risk in a milling system and their inherent problems and possible solutions:
Venting:
Use of a rupture disc/panel to relieve explosion pressure. Venting is a cheap, reliable and low tech. operation and requires very little maintenance. Typically, vented systems are used in conjunction with large filter installations for the safe venting of pressure in the event of an explosion. This may be problematic dependant upon site layout and obviously, as this method vents product to atmosphere, it is not an option when dealing with potent, toxic or otherwise hazardous products.
Suppression:
Detection & suppression of an explosion before it can cause damage. This method of protection allows the system to be sited anywhere and does not compromise containment in the event of an explosion. However, a suppressed system does require periodic checking & maintenance and may require extensive system cleaning after operation which can be costly as well has holding up production. Probably the most significant point is that it does not actually prevent an explosion from taking place and may not be suited for use with sensitive, low M.I.E materials.
Inerting:
Use of an inert gas such as nitrogen or argon to reduce the oxygen level in the mill to below the limit that will support combustion. This method allows the system to be sited anywhere and remains the only practical solution to eliminate the possibility of an explosion. As such, it is particularly suitable for the milling of low M.I.E materials. However, this system does have high initial cost and the ongoing expense of supplying the inerting agent. Adequate protection against hazards of asphyxiation & “cryo burns” must also be implemented as well as provision for venting of added gas.
Containment:
Designed to contain the maximum pressure rise during an explosion. The milling system is built to withstand a 10 bar over-pressure situation without any venting to atmosphere. However, this setup requires a large and costly up rated filter and the question of where to site it which may be a problem if available space is limited. Contained systems involve a higher initial cost of manufacture and of course, they do not prevent an explosion from taking place. This may not be suitable for use with sensitive, low M.I.E materials.
Conventional Containment System with filters etc
Solution
To solve the problems of cost, complexity and sheer size associated with the options detailed above, Kek-Gardner has developed a highly innovative Closed-Loop design for its range of KEK Fine Grinding Mills.
Comparison between Vented, Containment with filtration and Closed Loop mill systems, shown in the same scale
Closed loop systems can be based upon the containment principle. However, they are much more compact and less expensive than traditional containment designs.The mill process gas is re-circulated around the system, which eliminates the need for filters, slam shut valves, etc. These systems offer easier cleaning with less chance of cross contamination. Rather than inducing airflow into the milling chamber, this new design incorporates a recycle loop around the mill system. Once closed up, and ready to run, no additional air is introduced into the loop and therefore there is no requirement to remove it after milling. The air carrying the product is continually re-circulated back to the mill inlet. This results in a much smaller mill system which is much cleaner and negates the need for dust filtration. Due to the compact nature of the closed loop system, it is particularly suited to a 10 bar explosion containment approach offering a compact, quiet running mill which can be sited anywhere. During relatively short batch runs, it is possible to provide a closed loop system which operates without any temperature rise problems. Kek-Gardner point out that, where longer runs are required, a chiller can be added to the system to maintain an ambient milling temperature.
For the ultimate in containment of toxic materials, milling systems can be enclosed in "gloveboxes". Closed Loop & Inerted Closed Loop systems are ideally suited for use within Gloveboxes. Their compact design requires a smaller enclosure with fewer penetrations through the walls. Where required, the gas flow through the enclosure can be chilled to limit the temperature rise of the mill.
Summary
Explosion protection and / or filtration are often a pre-requisite during the specification of a fine grinding mill system. The Closed Loop design offers a more compact and less expensive alternative to traditional methods. Benefits to the Closed Loop Milling process are typically:
• Minimal moisture induced into the mill, leaving a drier product
• Much simpler explosion hazard protection through inertion or containment
• Compact design so ideal if space is a consideration
• Easy clean with less risk of contamination
• Less complex therefore less expensive design
Kek-Gardner Ltd offers a range of Powder Processing Equipment including PPS Air Classifier Mills, KEK Universal Mills, Cone Mills and Kibbler Pre-breakers and Gardner Mixers.
For information on a demonstration of the Closed Loop System at our Test Centre:
Call: +44 (0) 1625 412000
Email: sales@kek-gardner.com
Visit: www.kekgardner.com
2010-10-06 10:46:55
It has been said that anything can be mixed in a bucket with a wooden spoon, but this simple expedient may be considered impractical for more than a bucket full of product. So if not a bucket and paddle, then what? There are several different types of mixing machinery on the market and it is quite possible that more than one type of machine will be capable of handling a given application.
The challenge is to find the machine that is best suited to you, your process and your budget.
Although the dictionary definitions of mixers and blenders are one and the same, the tradition established among the majority of mixer manufacturers is to define a mixer as one which mixes by virtue of a moving mixing element (agitator) within a static vessel and a blender as one that mixes (or blends) by virtue of a tumbling action of the vessel itself. The different types of mixers and blenders on the market include low speed and high speed horizontal mixers with interrupted spiral, paddle, or plough type agitators, vertical mixers, as well as double cone, drum, tumble and 'Y' type blenders, to name but a few. In addition, some horizontal mixers and blenders may also be used as continuous mixing machines. The selection of the type of the machine best suited to your process will in part be guided by the characteristics and requirements of the material to be mixed and for instance, whether it has high or low particle strength.
Plough and Ribbon Agitators
So what type of machine is the best for you? Very simply it’s the one that achieves the desired product quality at a cost that falls within your budget for the purchase of the machine and it’s subsequent operational cost.
