Sani-Mega spray heads cut cost of tank cleaning

Alfa Laval's Toftejorg tank-cleaning systems are used in the process industries and brewery, food and pharmaceutical sectors.

Not only do they bring tanks to specified hygiene levels, but they improve process performance and cut water, energy and chemical consumption.

In the food industry, rotary spray cleaners remove burnt-food residues and biofilm and clean tanks equipped with agitators or baffles.

In the pharmaceutical and personal-care markets, Toftejorg products meet the hygienic standards of the FDA, EHEDG and other approval authorities and are suitable for a range of viscous, foaming and thixotropic products.

Alfa Laval's Sani-Mega rotary spray heads are ideal for CIP (cleaning in place) of silos and other dairy storage vessels.

Installations in Europe and the UK have produced savings of 50 per cent or more in pre-rinse flow rates when used to clean raw-milk silos: sufficient to pay back the initial capital investment in 12 months or less.

These savings are based on dairies with a typical throughput of several million litres of milk every week and that had previously used cleaning methods such as high pressure, high speed, fixed or rotary spray balls.

One of the most common arrangements of spray balls involves two fixed spray balls in the top dish of the tank with a third located near the bottom-mounted agitators.

This kind of installation operates at high speeds (250rpm) under applied water pressure and deluges the interior of the silo with water.

If a dairy performs 25CIP operations every week on raw-milk silos and uses approximately 16,000 litres of fresh water for each operation, its total water consumption is close to 400,000 litres per week.

This could add up to an annual water effluent charge of GBP50,000 or more, depending on the location and the local environmental regulations.

In stark contrast with the deluging action of the high-speed spray balls, the Sani-Mega is a gear-driven unit that operates at low speeds (5rpm) and cleans through impingement and high levels of turbulence.

It scrubs the silo's sides with fan-shaped jets that cascade down the walls to produce a vortex action once they reach the silo bottom and outlet.

An internal turbine and gear system enables the cleaning process to be accurately controlled.

The option of a feedback system enables the whole process to be recorded and repeated indefinitely.

While a typical spray-ball would use 5,500 litres an hour of fresh water for each CIP cycle, the Sani-Mega rotary spray head slashes the required volume to around 2700lph.

It also does the same with energy costs.

For optimum CIP efficiency, the silo walls must be heated to 70C.

The Sani-Mega's fan-shaped spray transfers heat to the internal skin more rapidly.

Consequently, even though water usage is reduced by 50 per cent, the silo attains optimum temperature as quickly as with a spray ball and frequently even quicker.

On average, payback for replacing spray balls with Toftejorg spray heads works out at 10-12 months, depending on the number of silos involved and the local environmental legislation governing white-water disposal.

Llandyrnog Creamery, a hard-cheese producer, discovered for itself the benefits of efficient tank cleaning.

It replaced static spray balls in its six raw-milk storage silos with Alfa Laval Toftejorg Sani-Mega rotary spray heads.

This increased the efficiency of its raw-milk tank-cleaning operations by 35 per cent while reducing water usage by 30 per cent.

Llandyrnog processes one-million litres of milk every day, to make 20,000 tonnes of Cheddar, Double Gloucester and Red Leicester a year.

Raw milk is stored in six 160,000-litre capacity silos that are cleaned on a daily basis.

The creamery's CIP (cleaning in place) routine involves a pre-rinse using water recovered from the final rinse, a hot wash with a one per cent caustic solution, an intermediate rinse with fresh water and a sterilant phase followed by the final rinse using fresh water.

Water is drawn from the creamery's own bore holes and an average of 400,000 litres is used every day.

The CIP regime was originally devised for fixed spray balls installed at the same time as the raw-milk silos in 1974.

The fixed spray balls used large volumes of water in a process that was both water and energy intensive; in addition shadowing occurred in areas where the water lacked sufficient force to dislodge accumulated product.

The large volumes of water involved also put a strain on the CIP system's pump and the process had to be frequently stopped to scavenge the tanks.

As part of a GBP3m improvement programme, the creamery trialled a single Toftejorg Sani Mega rotary head; the results were so positive it rapidly installed the same equipment in the remaining five silos.

Llandyrnog Creamery quickly reached optimum cleaning efficiency.

Since installation of the Sani Megas, sufficient savings have been made in energy, time and water usage to pay back the original investment.

Cleaning times have been cut from 43 to 28 minutes per silo.

The standards of cleanliness have also been improved.

Total viable count (TVC) and other standard test procedures demonstrate higher levels of hygiene and the elimination of shadow areas.

Alfa Laval has developed a software programme called TRAX that simulates actual tank conditions and the performance of the machine in terms of detergent distribution and wetting intensity.

Consequently, the optimum configuration can be determined before the equipment is installed.

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