MILKING MACHINE MANAGEMENT VOLUME 1 2 FOREWORD Milking Machine Management, Volume 1, to a healthy and highly productive herd. is the sixth in a series of management Veepro Holland is indebted to those who manuals published by Veepro Holland and contributed to this manual, particularly the first of two volumes on milking machines. Ing. Wim Rossing of the Institute of Agricul- The cooling and storage of milk, and testing tural Engineering (IMAG-DLO) of of the milking machine will be described in Wageningen and Ing. Kees de Koning of Volume 2. Through these manuals Veepro the National Reference Centre for Live- Holland aims to provide you with useful stock Production (IKC) of the Ministry of management information. Dairy cattle Agriculture, Nature Management and worldwide have to be managed well to Fisheries at Lelystad for their constructive utilise their genetic potential to full extent. criticism. No single booklet can cover every subject We would like to thank the IPC-Livestock/ as diverse and complex as dairying. Dairy Training Centre 'Friesland' at Oenkerk Nor will probably everyone associated with for their valuable assistance in the prepara- dairying agree on all points covered in one tion of this manual. publication. But we of Veepro Holland Many thanks also to those associations and believe the combination of this manual publishers who permitted us to use various and other publications on the subject may data and illustrations. broaden your knowledge about milking machines and will subsequently contribute VEEPRO HOLLAND Publisher / Editor : VEEPRO HOLLAND Information centre for Dutch cattle P.O.Box 454 6800 AL ARNHEM HOLLAND / Tlx: 45541 NRS NL / Phone: ** 31 85 861133 / Fax: ** 31 85 861452 Design & Realization : D vision Copyright © VEEPRO HOLLAND. Publication from this manual is permitted only after approval of VEEPRO HOLLAND and on condition of statement of the source 3 INTRODUCTION The milking machine is probably the most milking machine or parlour, they all work important piece of farm equipment at a according to the same way principle. dairy farm. Each day of the year begins and ends with milking. It should be kept in We will now have a closer look at the milking machine and the way it functions. The testing and mainte- nance of milking equipment and the cooling and storage of milk will be described in Volume 2 of Milk- ing Machine Manage- ment. The cleaning, disinfection, and maintenance of milking equipment is described in the Proper Milking Management manual. The milking equipment is probably the most important piece of farm equipment mind that the milking machine has got to THE CONSTRUCTION AND FUNCTION OF milk cows twice a day, no matter what THE MILKING MACHINE happens. For this reason, proper under- standing of the milking machine and The milking machine consists of the follow- regular maintenance is of utmost impor- ing key components: tance. • the vacuum pump In handmilking the pressure is increased by • the vacuum pipeline squeezing the fingers around the teat so • the interceptor, vacuum tank or moisture the teat sphincter will open. The approach trap in machine milking is different; instead of • the vacuum regulator or controller increasing the pressure within the teat, one • the vacuum gauge lowers the pressure outside the teat canal, • the vacuum and drain taps which causes the teat sphincter to open, • the pulsators while a pulsating vacuum between the • the milk pipeline teatcup and the liner forces the liner to • the cluster assembly and/or buckets • the recorder jars and milkmeters open and close, thus stimulating blood • the sanitary trap circulation. • the receiver unit The major changes over the years related • the milk pump and milk filter to plumbing and ironwork of the milking machine, made the transition from a The basic lay-outs of the main types of bucket milking system to a milking parlour milking machines are shown in figure 1 possible. But no matter the design of the (see page 4). 4 Figure 1 The basic lay-outs of the main types of milking machines.(Source: Machine Milking and Lactation) regulator vacuum tap vacuum gauge Bucket air pipeline machine interceptor vacuum tube pulsator long pulse tube teatcups long air claw bucket milk tube vacuum pump vacuum gauge pulsator airline pulsator milk pipeline Milking pipeline long long machine sanitary milk pulse trap tube tube receiver air milk pump pulsator airline milking vacuum line milk transfer line Recorder pulsator machine recorder jar air = air = milk = air & milk The vacuum pump minute. The capacity of the vacuum pump The function of the vacuum pump is to is expressed in litres of free air per minute rapidly extract air continuously from the and should be larger than the sum of the milking machine system. An air/vacuum reserve capacity, the combined "air pipeline connects the vacuum pump to all consumption" of the milking units and the parts of the system where vacuum is pulsators, and other ancillary equipment to required and is together with the vacuum maintain vacuum at a certain level. pump regarded as the lungs of the milking The required size of the vacuum pump will machine system. Most milking machines depend on: operate at a set vacuum level between •the type of the installation (either buckets 40-50 kPa. This is sufficient to extract milk out of the teats. Under normal weather condi- tions the atmospheric pressure is about 100 Table 1 Conversion table for units of pressure kPa (1 bar) or 29.53" Hg or 75 cm Hg. kPa inches Hg cm Hg See table 1 for conversions. vacuum vacuum vacuum The capacity of the vacuum pump is the 41 12 31 volume of air (at atmospheric pressure) 44 13 33 displaced under working conditions and at 47 14 35 a known number of pump revolutions per 50 15 37 5 or milk pipeline with jars or milkmeters) The number of milking units influence the •the number of milking units required size of the vacuum pump •the ancillary equipment •the number of milkers •the cleaning system •the geographic altitude When installing a milking machine, the minimum standards have to be closely observed, such as those of the International Standards Organisation (ISO). The current ISO standards are under revision. Table 2 gives some examples for the desired vacuum pump capacity. Table 2 Recommended minimum free air capacity of the vacuum pump in litres per minute and number of units at sea level. (Source: IKC). Number of Bucket Milk pipeline milking units type installation installation (circulation cleaning) 2 250 l./min. 330 l./min. 3 300 4 350 425 tees is recommended and the installation 5 400 of knee-pieces should be avoided under 6 530 675 all circumstances, owing to their high air 8 1000 resistance. If the vacuum pipe is part of the 12 1400 cleaning circuit, it should be made of 16 1700 stainless steel, glass or PVC. 20 2000 The pipes should be properly supported to Atmospheric pressures and distances prevent sagging, which is often seen in above sea level will change the output of many older machine milking installations. the vacuum pump. Table 3 shows the Make sure that the vacuum pipeline can correcting factor for true capacity. withstand an internal pressure of up to 200 kPa at all prevailing temperatures. The internal pipeline diameter should be Table 3 Elevation correction factors for cal- such that a drop in vacuum in the pipes culation of the correct size of vacuum does not exceed 2 kPa. See table 4 for pumps. standards for vacuum pipeline diameter. Elevation in Multiplier factor Normal metres above for needed atmospheric sea level pump capacity pressure in kPa Table 4 Standards for the minimum vacuum pipeline internal diameter in relation < 300 1.00 100 to the quantity of air extracted per 300 - 700 1.07 95 minute at a constant air flow for 700 -1200 1.16 90 pipelengths shorter than 30 metres. 1200 -1700 1.28 85 (Source: IKC). 1700 -2200 1.45 80 Airflow Internal Section surface litres/minute diameter area in cm² The vacuum pipeline < 200 25 mm (1") 5.0 The air pipes connect the vacuum pump 200 - 600 38 mm (1.5") 11.3 to the various milking units and are usually 600 - 1000 50 mm (2") 20.4 made of galvanised steel or PVC. 1000 - 1700 63 mm (2.5") 31.2 The lowest possible number of elbows and > 1700 76 mm (3") 45.3 6 The interceptor The milking parlour is the heart of the dairy farm An interceptor vessel or moisture trap is fitted close to the vacuum pump to collect moisture and dirt, preventing it from enter- ing the vacuum pump in order to avoid damage. It should be fitted in a position where it is easily accessible for cleaning. It is recommended to provide it with a float valve which closes off the vacuum when liquids (milk or water) within the interceptor rises too high, and a self-sealing flap valve on the outlet which automatically opens when the pump is switched off. In accord- ance with the milking system in use, the interceptor should have a minimum capac- ity of at least 15 litres but preferably more. The vacuum regulator The vacuum regulator is the brain of the entire machine milking system and should automatically maintain a steady, desired vacuum level. The regulator may be operated by either a spring, weight or diaphragm. The regulator is pre-set at the desired vacuum level, so when the vacuum in the plant increases above the pre-set level, atmospheric air is admitted into the system until the required vacuum is reached. If the vacuum drops during milk- ing, the vacuum regulator might not function properly, the pump capacity To facilitate reading, the diameter of the might not be large enough, the pump is gauge should be at least 75 mm.