The Home Separator Dairy

New Zealand Journal of Agriculture, Volume 59, Issue 6, 15 December 1939, Page 496

The Home Separator Dairy

Correct Use of Separator a Vital Point in Dairy Farm Practice

Contributed by the DAIRY DIVISION

THERE are' two small points in connection with the delivery of milk arid ’ cream to a • manufacturing dairy with ' which all dairy farmers should be familiar.. Regulation 11, for instance, requires that no cream, skimmed; or partly-skimmed milk shall be added to the milk delivered to a factory. Clause (1), Regulation 22, requires delivery of milk to a cheese factory at or prior to 9 a.m. each morning; .. ■.■'■• - ; ' The reason for the second will; be obvious, but in view of the fact that milk is generally paid for on a butterfat basis, the reason for the first may .not be understood. Where casein is being made, the addition of cream will obviously upset the equity of the payment for' the former, and in the case of a cheese factory paying on yield, the ratio of casein to fat will be upset by /the addition of skim milk or cream. As these articles up to the present have dealt with dairies supplying milk, we now pass on to those in which the milk is separated and cream only is delivered. Points already dealt with apply equally to this class of dairy,

but 7 the separator adds further responsibilities to those already mentioned. First : Step The separation of milk on the farm is the first step in, the manufacturing process. Experience'.has shown, that milk which is drawn under clean conditions, either by hand or machine, and run through a separator as milking is proceeding produces better cream than does milk which ,is delivered once daily and . requires ' re-heating before separation, provided always that the ■ cream is given, proper . attention after it is separated, and is delivered daily. Further, if proper care is taken with the separation, the fat losses in the skim milk should 7 be lower, as the milk is at . that , stage at the best temperature for separation. ■' It is doubtful, however, whether under the varying conditions obtaining on dairy farms this actually happens in practice. A . loss of 2 per cent, of the fat credited is not unusual in creamery practice, so that it is probable that in farm practice the average is not less than 2 per cent, based'

on the fat lost in the skim milk only. If this is correct, the supplier of cream is therefore paid for at least 2|- per cent, less fat than if he delivered the whole milk. Care of Separator The care of the separator is consequently a vital point in dairy farm practice under home separation conditions. If the size of the separator is such that the milking and separating proceeds simultaneously, the temperature of the milk and regularity of the feed to . the separator will be automatic during the flush months, and' an even speed of the bowl will ensure the highest efficiency in separation. This efficiency will not be so high during the slack months of the year, when separating cannot be started until there is an accumulation of milk in the vat and the temperature is . not maintained. The same position will also arise if the separator is too large, as efficiency in separation depends on even feed to the separator, even speed of the bowl, and even temperature. If the speed of the bowl is too high, the feed not sufficient, or the milk cold, the test of the cream will rise and the weight of cream will fall. These will cause loss of fat through the accumulation of thick cream in the discs, covers, etc.,, and the third will reduce, the skimming efficiency by . increasing the viscosity of the milk. Low speed and over-feeding ; will cause the test to drop, will increase the weight of cream, and will reduce the

skimming efficiency. In the case of either an increase or a decrease in the test it may -be found that if the test is multiplied by the. weight of cream and divided by 100 the pounds of butterfat will be the same as it was before the alteration. Variations Apart from the separator, the test of the cream will vary in . sympathy with any rise or fall in the test of the milk, whether due to weather conditions, seasonal changes, change of feed, and : many other causes. A separator is designed to deliver at the cream spout a certain percentage of the weight of milk which passes through it. If it happens to be 101 b of cream from lOOlbs. of 3.6 per cent, milk, the test of the cream will be approximately 36 per cent. If 1001 b. of 4 per cent, . milk is put through the. same separator -it will deliver approximately 101 b. of 40 per cent, cream, providing the cream regulating screw has not been altered in the meanwhile. If the cream regulating screw is fitted on the cream v outlet and you wish to raise the test of your cream, screw it in. To reduce the test, screw it out. If it is on the skim milk outlet, screw it out to raise the test and in to reduce it. If the feed tank is too high, altering the cream screw may not affect the test, because the amount of milk passing through the bowl is in excess of its skimming capacity. In this case, reduce the height of the tank stand or raise the separator. Set the screw to deliver cream testing about 40 per cent. Nothing is gained by skimming too thin, and there is a definite loss by skimming too thick. ;.y . If the separator is not running well, the Farm Dairy Instructor will be able to help you to avoid the loss which is sustained every time you use it. All that is wrong in most cases is that some small part wants renewing. It may be quite unnecessary to buy a new machine, and the Farm Dairy Instructor will be able to advise you on this point. ' Cleaning Important 1 It should not be necessary to state that a separator should be dismantled every time it is used, and thoroughly washed and scalded immediately separating is finished. A separator which has not.been washed since the time it was last used does not skim efficiently, and, if too small for the size of the herd, may even require wash-

ing after half the herd has been milked. If left unwashed after the evening’s milking/ the deposit in the bowl will become detached and cause a 'bad flavour in the cream, so that there may be two causes of loss as the result of this neglectloss of fat . 'and a lower grade of cream. • <■/ The washing is a simple process, as each part. can be reached with suitable brushes, and washing soda and warm water is all that is needed to remove the milk and prepare the whole of the parts for scalding. If a copper is used for boiling the necessary water, they can then be dipped into it, and in a few moments they will be dry. They should then be hung up in the sun, but protected from

rain, and should not be re-assembled until- wanted for use. A separator treated in this way will have a much longer life than one that is neglected, and will do more efficient work while in use. ■ V : > . ’ • • v When separating is finished a small quantity of skim milk should be run through the bowl to remove the cream. This skim milk should be caught, under the. skim milk spout before separating, is finished. A case of second-grade cream has been traced to skim milk which was taken for this purpose from an unclean milk barrel. Do Not Use Water Water, and especially . hot water, should never be used, as it may remove

some of the deposit from the bowl, and too much of any liquid will cause a drop in the test of the cream. Careless handling of skim milk causes a most offensive smell in a separator room, and this smell is frequently absorbed by the cream. For this reason, skim milk pumps must be. fitted with detachable tinned brass suction pipes. As already stated, the cream should be thoroughly cooled as it leaves the separator, as this will check the growth of . any germs which it may contain, and will also reduce any feed flavours which are present. Each skimming should be kept in a separate vessel at least until just before dispatch to the creamery. Even in the best-kept dairy it is a wise precaution to remove it from the separator room to a shelter at some distance from the shed where it ? is '. not exposed to the sun’s rays and is protected from the entry of insects and vermin of all kinds. If a cold spring is available the can should be placed in it. A sun-proof ( cream stand must be provided at the roadside if the cream is to be collected by a cream lorry. Should- this 'stand encroach on the

road, the county council or other , local authority should be approached for permission to erect' it. Otherwise, the owner of the stand can be held responsible for any accident which may be caused by it. Up to this point the owner of the cream is responsible for the care which is required by the various regulations, but *as soon as the carrier, takes delivery he or his employer is respon-

sible until the cream reaches the creamery. . CORRECTION. The opening sentence in the article “Cleaning of Dairy Equipment” in last month’s “Journal” began with the words: “The annual procedure to be followed in cleaning . a milking machine.” The sentence should have read: “The general procedure. . . .”