1 August 1997

Use your screwdriver to save time and money

Preventative parlour maintenance can save producers valuable time and money. Andrew Pearce reports

A STITCH in time saves nine, goes the saying, and few places around the farm bear that out better than the milking parlour. Its a complicated place, with much potential earning value hanging on it. And its needed at least twice a day, 365 days a year.

Yet dairy farmers are not always the keenest on maintenance. Despite parlour complexity a lot of simple stuff can be done to keep everything ticking over, the cows healthy and milk quality high, all without calling in a service engineer. Preventative care takes nothing more technological than a screwdriver, with Grier Coventry, service and installation manager for Gascoigne Melotte, suggesting that DIY should stop when things need serious dismantling.

The checks suggested here apply to most modern set-ups. A good cowman makes as a matter of routine, along with keeping an ear cocked for changes in pulsation, and an eye open for air bubbles where none should be – both are clear pointers to trouble. But even with reasonable vigilance things can be missed, and neglecting any of these simple points can trigger an unnecessary specialist call-out.

Although there is a natural priority of care (animal health, milk quality and equipment reliability, in that order), its easiest to look at maintenance by time interval. So items below are grouped this way.

Daily checks

&#8226 Two points must be looked at every time. System vacuum is one – depending on plant and milk line height, this should generally be 44kPa in low-line parlours and 50kPa in high-line ones.And the sanitary trap must be milk-free. Liquid here points to trouble with the milk receiver, as float switch or milk pump failure. The sanitary trap is the first lineof vacuum pump defence,with expensive damage a possi-bility if milk gets through it.

&#8226 Air bleeds are vital in vacuum systems, as milk wont flow or rinse water wont rinse unless air has a way in behind it. Theres a tiny bleed hole in every cluster. Flies exploring for milk can be sucked in and bung it up, with the result that liquid wont clear before vacuum shuts off. Prick holes clean.

lLike the clusters, individual milk meters have their own bleed hole. If blocked, milk or rinse water stays put.

&#8226 Have a look in the milk receiver after rinsing. Some have a steel door, others are clear. Water should empty through a receiver drain, but wont if the latter blocks with straw or chaff sucked off the teats or through a fallen cluster. Keeping the drain clear stops water or sanitiser mix going to the bulk tank on start-up.

&#8226 An obvious one, this, but no vacuum pump oil means no vacuum pump. Watch for flow when the unit is running. With oil recycling systems (as above) drain water and sludge from the tap then top up. Its vital to use only vacuum pump oil – stuff for compressors or engines will separate out, then gum up oil ways and pump vanes. With oil separator systems, drain used oil and sludge from the receiver and throw it away.

&#8226 Another simple one. In automatic wash systems, check theres enough chemical. Some, like Gascoignes Aquastar, work out how much is left after every rinse and flash a warning when the supply is running low. Wash water temperature should be as recommended by the plant maker and chemical supplier.

&#8226 Straw or chaff in the cluster wash jetter outlets is bad news for hygiene. When the wash system is running, rock each shell and listen for clear, equal hissing.

Weekly checks

&#8226 Splits round the liner edge hurt the vacuum and are uncomfortable for the cow. Internal holes are harder to find, but liquid leaked from the liner will turn up in the pulse tubes. While youre at it, bend each tube and look for ozone cracking; legislated reductions in rubber carbon content are eroding material durability. Tougher, more expensive silicone replacements last longer.

Monthly checks

&#8226 Main vacuum lines to the parlour branch out of the distribution tank. Open the flap valves, peer in and clear out any sludge.

&#8226 The interceptor is the last-ditch defence for the vacuum pump against liquid entry. Clear any sludge and check that the ball valve is in place and working.

&#8226 Re-tension vacuum pump drive belts as needed, following makers recommendation on tightness. When paired belts are getting past it, replace both – a single new one will wear quickly as it will do most of the work.

Three-monthly checks

&#8226 The vacuum regulator compares actual system vacuum with the required level pre-set on the unit, then bleeds in air to equalise them. Clean its filter(s) with a bristle brush or replace. Moving into the parlour, pulsators may draw air from a manifold system or individually. Manifolds have a single dry element filter which needs to be brushed clean – monthly in dusty parlours. On non-manifold set-ups, each pulsator has its own small filter under the unit cover. Brush clean and put back, or replace.

Liners should be checked weekly; splits in the edge reduce vacuum and are uncomfortable for the cow.

Producers should clear any sludge from the interceptor every month, says Grier Coventry, and check that the ball valve is in place and working.

Clean vacuum regulator filters with a bristle brush or replace every three months.

Planned maintenance

Although do-it-yourself checks are the best way to head off silly breakdowns, long-term plant reliability is rooted in specialist maintenance. These days, suppliers of new equipment are required by law to detail what needs to be done and when, and this schedule can provide the basis for a maintenance contract.

Along with other major parlour equipment suppliers, Gascoigne Melotte suggests users consider such contracts. Usually carried out by dealers rather than the makers themselves, visits are commonly every six months or annually with cost depending on parlour size, complexity and location. Your local parlour equipment supplier has details.