Ninth paper

SUBJECT: THE ECONOMICS OF AUTOMATED PLANT PROCESSING AND BOTTLING B Y R. E. B A I L E Y

Dairy Manager, United Co-operative Dairies Ltd.. Hyde, Cheshire

I propose to discuss the economics of automated plant against a background of experience with a certain processing and bottling dairy. In present day terms, this particular dairy is of medium size with a throughput of 45,000-55,000 gal milklday. Almost the whole of the supplies are ex-farm and apart from 4,000 gal delivered daily in cans, it is all bulk collected milk. For a period each year beginning in the flush, up to 10,000 gal/day are cooled for despatch elsewhere, and in the autumn a relatively small amount of accommodation milk is bought in. Of the daily intake, about 15,000 gal go to the production of sterilized milk and about 35,000 gal are pasteurized, mainly for the pint bottle trade. As some of this milk is homogenized the pipe line systems make provision for both types of milk to be handled simultaneously. Raw milk storage capacity consists of three 10,000 gal silo tanks and two 5,000 gal storage tanks.

The first moves towards any kind of automation were made about 10 years ago with cleaning-in- place systems using key pieces. This was an ad- vance on manual methods but at the same time it had its limitations. However, our satisfaction with this plant was sufficient to give us confidence to install a fully automated milk flow and cleaning system. This takes in all raw milk pipe lines, milk storage and finished milk tanks, and the pasteurized milk pipe lines. This installation has been in use for the past 2 years.

There is a separate automated system for dis- charging and washing bulk collection tankers and the cleaning of raw milk pipe lines. This is housed in a purpose built collection tanker reception bay which can handle 30 or more tanker loads/day and is capable of further expansion. Tankers drive into one of four bays where the milk is discharged and the tanker cleaned on a pre-determined pro- gramme. This unit was completed in 1966. The building cost E20,OOO and the equipment, i.e. pumps, pipework, CIP set, detergent tanks, etc. a further &14,000. Amortization costs and overheads are about &3,00O/year. The operational saving in man-power is 2 men but with 365-day coverage this becomes 3 men. There is therefore a definite saving and there is the added bonus that with an automated system the job is carried out smoothly,

more hygienically and with a greater degree of reliability. Four tankers can be handled simul- taneously, with 2 discharging milk and 2 cleaning. The total turn round time, allowing for sampling, testing, discharge and cleaning is under 1 h. It may be considered that there is little more than a break- even cost situation. Nevertheless the overheads on this plant are likely to be much more stable than the labour costs, so that as time goes on the saving will increase rather than diminish. Before we installed this plant one of the fears lurking in the back of our minds was that the cost of elec- trical maintenance might be very high but so far we have not found this to be so. Regular maintenance is carried out by the resident electrical staff.

The advantages of automated milk flow and cleaning are well known. Briefly, these are :

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Processes of work are more expeditiously achieved with a smaller labour force. Cleaning is more consistent and reliable and again subject to more efficient control. Here I may mention that at the end of a long day an effective cleaning programme is as easily achieved as at the beginning of the day, but with manual cleaning this is less likely when operatives are tired and may be in a hurry to get away. It allows bottling and other plant to be worked the full day as staff are not required to be drawn off this work for cleaning duties. With an in-place system there is an obvious reduction in damage to pipework, valves and floors which inevitably occurs from time to time when daily dismantling is necessary. With manual cleaning there are some sections which cannot be conveniently cleaned whilst the rest of the plant is running. Operatives cleaning pipework may be in the way of other operatives, but with an in-place system as soon as a section has finished its work, cleaning can unobtrusively proceed. . -

vi. For certain large installations with silo tanks and long runs of pipework, an automated sys- tem is essential. It is neither hygienic nor is it effective to clean large silo tanks manually.

The issue for management is at what point in the

Journal of the Society of Dairy Technology, Vol. 25, No. I, January, 1972 31

scale of a dairy’s operations is it beneficial to adopt an automated system. This can only be determined by weighing the benefits against the cost and these will vary with the size of the dairy, its lay-out, length of pipeline, the variety and sequence of operations and the length of its working day. In seeking quotations for systems it is sometimes pos- sible to save money without detriment to the effi- ciency of the dairy by altering the sequence of some operations. For example a certain storage tank is always cleaned at a particular point in the day. Could it be done at some other time without re- ducing efficiency? A thoughtful reappraisal of all the circumstances of the day’s work may result in a re-scheduling of some work and allow a less com- plicated system to be installed. Some flexibility in the use of plant and the sequence of its use is necessary, e.g. the washing, emptying and filling of storage tanks, but to carry this too far may add considerably to capital costs. Careful consideration of all the cleaning operations carried out in the course of a day’s work can keep the number of simultaneous cleaning operations to a minimum of say one or two, whereas just to install a system to do exactly in the same time sequence what was done with a manual cleaning system will, in all probability, prove more expensive than is really necessary.

In discussing with the manufacturers one phase of the system, it was found that a second raw milk discharge point was only used about 30 times a year. Although infrequently used, it was valuable when it was required but it was not thought worth- while to bring it within the automated system. By leaving it out E1,OOO was saved. Another example of an even greater saving came when we did not include the whole circuit of the hot milk pipes running from the sterilized milk pre-treatment plant to the hot milk fillers. There are two such lines and all that is necessary to clean them is to connect manually the two lines with a piece of flexible hose. The pre-heater and homogenizers then link in to form one continuous cleaning circuit and the hot milk balance bowl becomes the detergent tank. As the blend of detergent required for this cleaning operation is different from that used in the other cleaning circuits, separate provision for this would have had to be incorporated in any automatic sys- tem. It was simpler to leave this outside the system which obviously reduced the cost substantially.

Each additional automatic operation with 6 or 8 valves at El00 each plus pipework and electronics for the circuit substantially increases the cost of the installation. However, if the job is a regular daily one then the capital expenditure to automate this is likely to prove worth-while.

The main automatic system controls the milk flow and cleaning to and from 5 storage tanks and the processing section, the pipe lines from the finished milk tanks to 3 bottling lines including

that for pasteurized milk drawn off for bulk or going to cartons. It makes provision for handling both pasteurized and pasteurized homogenized milk. The system has 16 cleaning circuits with 180 Zephyr valves and 8 Flo-splitters. The cost in- cluding installation was E62,000, of which E56,OOO was for the supply and installation of pipework, valves and programme equipment. The remaining E6,OOO was for services, electrical wiring and build- ing alterations. This gives depreciation over 10 years with interest and other charges of about &9,00O/year. We estimate that we save at least 200 h labour/week. Much of this would be over- time at premium rates. Again, we are just breaking even, but we have a more efficient and smoother job with automatic plant and with the mounting cost of labour the advantage of automation will increase more and more with every passing year.

In another dairy of similar size with a 13-circuit system at about the same cost, the management said that they believed their labour saving was con- siderably more than 4 men. Some comparisons are difficult to make because until recently we did not have such large storage tanks. How these could be cleaned by hand and how much time it would take to do this effectively is difficult to determine.

One interesting refinement in this particular plant is that every pump in the cleaning circuit is moni- tored so that at the end of the day there is a com- plete record of the time of operation of each pump and hence a check that every circuit programme has been followed through.

If I am asked bluntly whether an automated plant will give enormous economies, which will allow capital cost to be recouped in less than the normal depreciation period, the answer, in my limited experience, is ‘No’, but there are some economies and if the question is posed in terms of cost effectiveness, then automation gives consider- able advantages. No self-respecting dairy can really contemplate its equipment being cleaned by operators physically standing in tanks to scrub them. With large installations it is not safe and certainly not effective. We must offer conditions of employment comparable to those elsewhere in industry. Automated plant has its place in this but in planning its installation a management should consider carefully the way the work is organized, why each operation is performed and why it occurs in a particular sequence. If this is done then the manufacturers can devise an automation system which is tailor-made for that dairy so that the maximum benefit is obtained at the lowest cost.

In this paper I have kept to a consideration of the automation of milk flow and cleaning opera- tions. Here a dairy can achieve a high degree of automation. No doubt as the years go by the area of automation will be extended and contribute to greater efficiency and more congenial working conditions.

32 Journal of the Society of Dairy Technology, VoZ. 25, No. I , January, 1972

Boilers are another example of automated plant used at dairies. Bottling lines are, as yet, highly mechanized rather than automated although there is a degree of automation in some crate marshalling and de-marshalling systems. Here there is scope for considerable labour-saving with relatively small expense so that the capital outlay may be recouped in two or three years - but this is another story.

DISCUSSION Mr. R. M. Stuart: I am pleased to have the opportunity of opening this discussion on Mr. Bailey’s paper and I feel that you will all agree that he has covered his subject in a comprehensive manner in the limited time available to him.

However, the economics of automation will vary from one dairy to another and will depend on the type and size of the unit and also how the unit is operated.

Mr. Bailey did not discuss detergent savings by recla- mation or savings on water by reclamation of final rinse water for re-use on pre-rinses. Perhaps he could enlighten us as to whether or not his system makes these savings.

My company decided to install an automatic product routing and CIP system 3) years ago. Having made the decision, we like Mr. Bailey were worried about mech- anical and electrical aspects of the system, believing at that time that we would get into all sorts of difficulties that could have disastrous results on the product or im- pair efficiency. However these fears fortunately did not materialize. It must be admitted that in the initiat stages we did have our difficulties. These were quickly rectified and we have maintained a high degree of efficiency over the three-year period.

In the early stages we found that, although the system was fully safeguarded and the use of Flo-splitters elimi- nated the possibility of product contamination from the CIP system, of course the system was not idiot-proof and if we had attempted to safeguard against all eventualities, the cost would have been astronomical. Certain safe- guards were, nevertheless, required to ensure against any alterations to the cleaning programme by the operator. To achieve this we decided to record the cleaning opera- tions by installing a recording system in the Manager’s office. This system records the circuit selected and moni- tors the complete operation of each cleaning cycle.

Although, like Mr. Bailey, we have experienced very little trouble with the system and our engineers handle the additional work without increase in staff, we felt it would be advisable that the manufacturer’s engineers should be called in to examine certain parts of the system from time to time. We felt that it was up to the manufac- turer to ensure that this specialist service and advice was readily available. We have now entered into a service agreement with them which covers the complete inspec- tion of the system on a twelve month basis. As our engi- neers work with the manufacturer’s engineers, our own staff are gaining knowledge and competence.

Mr. Bailey indicated that he estimates a saving of at least 200 h/week at premium rates and that at this figure he is at break-even point. We feel that our savings are considerably greater than his and our estimate is in the region of 300 h/week at premium rates. The capital cost of our system was similar to Mr. Bailey’s, and it is capable of handling 20 circuits. It should be remembered that a great proportion of the capital spent would have been required had we not installed automation. As we use silos, we would have had to install a bulk CIP set for this operation in any event. If we had used a key-piece sys- tem, we would have required the same amount of pipe- work and the same number of pumps, etc. In short, to assess accurately the economics of automation, I feel we should have to take the cost of the essential equipment

away from the total cost and use this figure to evaluate savings. I wonder whether Mr. Bailey would like to com- ment on this point.

An interesting difference between our two systems is that in Mr. Bailey’s system he used 180 Zephyr valves and only 8 Flo-splitters, whereas in our system we have 62 Zephyr valves and 19 Flo-splitters. Does he rely on Zephyr valves to isolate product lines and tanks from CIP and if so, has he experienced any trouble using this method?

In conclusion, may I say it is my belief that if we hope to achieve consistently high standards and maximum pro- duction with minimum staff and attract the personnel we require into the industry, automation is essential.

Mr. R. E. Bailey: I agree with Mr. Stuart that if a dairy has silo tanks then it is necessary to have some kind of automated cleaning system.

On the point about Zephyr valves I do not know why the manufacturers have recommended a large number of Zephyr valves rather than Flo-splitters. We had a number of teething troubles with the system in the first month or six weeks of use but we have had very little trouble since that time. One particular Flo-splitter gave us difficulties over a period but this was eventually overcome.

We have had no dificulties with extraneous water. As a matter of routine we monitor milk samples three or four times a day. There is no difficulty in doing this as we also check on the Hortvet each compartment of all bulk collection consignments.

I have referred to detergent savings. We do have a water recovery system. The addition of this cuts water consumption within the system to one third. To give an actual figure for tanker cleaning, 400 gallons of water goes down the drain with each circulation. The cost of washing a tanker is lop of which 6p is for water and 4p for detergent.

We last took down our tanker milk line in August of 1970, although we examine a section of it each week. We have not had to clean this with acid since the summer.

This brings me to the point made by Mr. Stuart con- cerning daily monitoring of the circuits. This is impor- tant because if cleaning is skimped by an operative who shortens the set cleaning programme, it is likely that thereafter there will be a build up of scale which will re- quire acid to remove it. It is important that once a clean- ing programme is found to be satisfactory it is adhered to each time the circuit is cleaned.

On detergent costs it is difficult to give a figure as each day we transfer the detergent which has been used, to clean the two pasteurizing plants to the CIP system.

For the bulk collection tankers we were using a bottle washing detergent but we have now changed to a spec- ially formulated one costing approximately 4p per tanker circulation.

The President: I would like to comment on the schemes which Mr. Bailey has been describing. Although the high capital cost puts a lot of people off, I wonder how much of this cost would have to be invested in the equipment even if it were used manually without automatic control systems. I think we might find that it is a high proportion and therefore we unfairly load the costs of such schemes against automation.

Mr. A. I(. Lloyd: I would like to emphasize that the differences between the number of valves employed and the savings achieved by the plants with which Mr. Bailey and Mr. Stuart are associated, show that each plant has to be treated separately and that one meets different circumstances and finds different savings when automa- tion is applied to different plants.

One of the reasons why less Flo-splitters were used on

Journal of the Society of Dairy Technology, VoZ. 25, No. 1, January, 1972 33

the plant described by Mr. Bailey was that this plant was engineered in phases and there was not the same require- ment for such devices. The Flo-splitter is used to separate physically one circuit from another and consists of a pair of mechanized U-bends. The mechanism is more compli- cated than the Zephyr valve and of necessity requires better maintenance effort and this has to be offset against a saving in the number of valves required.

Although both speakers have mentioned that the main- tenance cost of their automated systems has not been great, I think it should be pointed out that a high level of skill is required. The maintenance man has to adopt an intelligent approach to the solving of faults, otherwise he might turn a simple fault into a major problem.

Having estimated the cost of an automation system and shown that it is economically worth-while, there is another aspect to be considered. There will always be a minimum number of people required to run a plant, below which one cannot go. It is vital that these people are usefully employed, so that if an emergency occurs, they are fully alive and ready to take action instead of being off the plant or half asleep. It is for this reason that one will never have a completely automatic plant and it

is necessary to have manual operation of those actions which are only carried out at infrequent intervals.

Mr. B. S. Thompson: I would like to ask what would be the cost of the effluent disposal from tanker cleaning, as in many cases this cost approaches the total tanker clean- ing cost quoted?

Has there been an increase in water consumption since introducing the automation of cleaning at your dairy?

Mr. R. E. Bailey: The cost of effluent discharge in our case is approximately 2p/1,000 gal. There has been a slight decrease in water consumption but simultaneously other plant has been introduced so that an exact com- parison between use before the installation of the system and after is not possible.

The cost of automation (excluding the section dealing with milk reception) was &62,000. Of this sum &28,000 was for automation of the silo tanks.

In answer to the President I would think that about one third of the cost of an automated scheme consists of items which are basic such as milk lines and pumps and would be required by a dairy without automation.

MANUFACTURE B Y M. T. H A R L E Y

Crumb Factories Manager, Confectionery Group, Cadbury Ltd.

At first thought the advantages of employing auto- mated plant seem obvious enough and this paper will show that on balance the principle of employ- ing such plant is right, but there are many con- siderations which go into arriving at the economic level for any one unit. Costings for capital expendi- ture are relatively easily obtained but the revenue expenditure will need a great deal more thought than is at first apparent.

Much has already been said about automated dairy plant. Since we have little extra to offer on this subject the following paper will deal with the economics of the whole plant, the advantages and problems alike. Before dealing with the subject in more detail it may help the reader to understand the problems which faced our company before embarking on a new scheme employing a high degree of automated plant.

The production of milk chocolate crumb is a well-established process. In this company’s case, the production was spread over 3 factories in the United Kingdom. It was becoming increasingly obvious that these factories would lose their milk to the retail market and therefore the need was to develop a 4th factory, receiving and concentrating milk followed by an automated crumb production unit. The maximum daily ex-farm intake involved was approximately 130,000 gal fresh milk, bulk and churn.

The original factories employed about 500 workers. Some of the plant was half a century old whilst the remainder was about 25 years old, all consisting of isolated items of plant linked into a batch process system. Maintenance was becoming more expensive as plant became obsolete and total output was also increasing as the national demand for the finished product accelerated. At first glance, the mechanizing of the process seemed quite feas- ible and schemes were prepared to enable trials to start. Certain isolated aspects needed special atten- tion but each was approached with a view to making a complete chain of events.

Following some 10 years of trials, analysis and refining, sufficient information was available for a fully automated plant to be built on a production scale. One can see that even in a period of 10 years, obsolescence was by no means impossible. Indeed it became necessary at one stage to cry halt to development and start to build with equipment that was currently available.

This was intended to be the end of all the previ- ous 10 years’ problems; however it was only the beginning of our experience in operating plant 168 h/week.

In our case the dairy function was not the main consideration. Since the dairy merely received milk, it was a relatively simple and cheap proposition to automate. The important consideration was to

34 Journal of the Society of Dairy Technology, Vol. 25, No. I , January, 1972