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Sugar Roller Mill Jack: Hydraulic Sealing Case Study in the Philippines


Chesterton Asia Pacific case study APAC0002 – Chesterton products – Chesterton EPS Hydraulic Sealing




Thanks to a special seal-lip geometry, Chesterton’s entire operating range of hydraulic seals are designed to provide zero leakage. The sturdy static lip stabilizes the seal to prevent rolling, while the negative-rake design eases the installation process for a hassle-free experience.

Products featured in the case study:

Chesterton 22K

Chesterton 18K

Background: The Sugar Industry


Sugar Roller Mills are used to extract the juice from sugarcane for the production of sugar. A roller mill is usually made of three rollers; a top roller, feed roller and discharge roller.

As you will notice, there is a hydraulic jack/ram cylinder attached on the top roller which presses the load down on the sugar cane while the cane is extruded through the feed and discharge rollers.

The performance of the hydraulic jack is critical for the juice extraction rate and quantity. If the hydraulic jack is leaking, it causes inefficient pressing and thus leads to inefficient juice extraction.

This can also lead to production delays while the cylinders are repaired.

One Sugar Milling Machine is composed of several roller systems (see bottom left photo), critical for the sugar extraction. Hence several cylinders are used.

PiescoHydraulics’ sales representative on-site work at a local sugar milling plant at Bukidnon, Philippines.

Example structure of roller press used for sugar extraction/ milling.(http://www.spec-cast.co.za/sugar.html)









Visualization of one whole sugar mill roller series. (Monteiro, et.al. (2012). An Integrated View of Sweet. Agricultura Tropica et Subtropica. 45. 12-19. 10.2478/v10295-012-0002-y. Accessed through Research Gate)

Actual Sugar Mill Jack upon arrival at PiescoShop.



In 2007, the hydraulic jacks of the 4th and last roller of a tandem B mill roller showed leakages three times during each milling season (each milling season is half-year long). With each leak, the operator has three options/scenarios: to leave the jack leaking, still in operation, until the next scheduled preventive maintenance which means hydraulic oil gets into the production process; to by-pass or turn off the jack until the next scheduled preventive maintenance which reduces the throughput of cane and therefore reduces the machine capacity; or to stop production and have the seal replaced. Seal replacement takes 12 hours to complete, which causes a considerable loss of production.

Root Cause

The existing seal is made of a locally produced urethane. As can be seen from the photo on the left, the urethane seal drastically shrinks and has completely lost its elasticity. A large part of the ram is made from bronze which results in a lateral load that causes additional wear. With the seal deteriorated and the ram heavily scratched, the cylinder leaks within a short period of time.


Replace the cylinder seal with a more appropriate and efficient material that does not shrink. Introduce bearing bands on the remaining length of the ram to prevent its metal-to-metal wear with the barrel. Make the hydraulic jack perform longer without leaking to minimize shutdown.

Shrunk piston seal and severely scratched/ worn-out bronze surface of ram.

Severely scratched barrel as a result of metal-to-metal contact with the ram.



Piesco hydraulics and Industrial Corporation presented the perfect solution, replacing the defective seal with Chesterton® AWC800 22K Piston Seal, combined with  Chesterton® 18K GFN bearing bands.

Chesterton® AWC800 is a diamine-cured thermoset polyurethane.

The innovative Chesterton sealing material is shrink-resistant, abrasion-resistant, wear-resistant, extrusion-resistant, non-absorbent, and operates with low-friction thanks to its molybdenum disulphide lubrication properties.

The Chesterton® 18K GFN bearing bands/MWR Coil TB prevents side loading and metal-to-metal abrasion on the adjacent metal surfaces on the remaining length of the ram.

The offered Chesterton solution prevents frequent leakages and extends the service life-time.

Reconditioned Barrel of the Hydraulic Jack.

Repair of Hydraulic Jack Ram.

Chesterton®AWC 800 22K Piston Seal and 18K GNF/MWR Coil TB Bearing Bands on the Jack Ram.





Client Reported

Upon introduction of the AWC800 thermoset polymer seal in place of the local urethane seal, shrinking has now been totally prevented. Metal-to-metal wear between the ram and barrel is also restricted due to the introduction of wear bands. Instead of shutting down 3 times per milling season, the cylinder lasts for five seasons without leaking.

  • 4th mill – (1st repair) – lasted from 2007 – 2012, that’s equivalent to 5 milling seasons
  • 4th mill – (2nd repair) – lasted from 2012 – present (cylinder isn’t leaking yet, reconditioning is done only for preventive maintenance), that’s 7 milling seasons and still counting.
  • 1st mill and 2nd mill – (1st repair) – lasted from 2008 – 2017 (cylinder isn’t leaking yet, reconditioning is done only for preventive maintenance), that’s 9 milling seasons
  • 3rd mill – (1st repair) – lasted from 2011 – 2016 (the main reason of reconditioning is not the quality of seal but the mechanical problem on the equipment that affects the rest of the parts of the equipment).
  • 3rd mill – (2nd repair) – lasted from 2016 – present, that’s 4 milling seasons and still counting.
  • 1st and 2nd mill – (2nd repair) – lasted from 2017 – present, that’s 2 milling seasons and still counting.


(1) Resealing Cost Savings

Under their old design, resealing costs per mill jack is Php. 16,000, multiplied by 2 (one roller: 2 cylinder), then multiplied by 3 (3 shutdowns), this would incur a total of Php. 96,000 cost/milling season.

The upgraded design provided by Piesco Hydraulics during 2007 cost Php. 280,000 however it lasted (without leaking) for 5 full milling seasons. Even then, the seals were replaced for preventive maintenance only (cylinder did not leak).

5 milling season seal cost (original design)  = Php. 480,000
5 milling season seal cost (upgraded design) = Php. 280,000
Total Seal Cost Savings for 5 years (5 milling seasons) = Php. 200,000*
* savings from prevention of hydraulic oil loss, prevention of production loss from downtime, and savings from efficient extraction not yet included

(2) Savings from Prevention of Production Loss

Scenario A) Assuming that the operator chose to by-pass one of the roller systems, this will result in a lower percentage of juice extracted compared to a roller system with all the rollers operating. In this case, the average extraction loss% is 4.25%.

One ton of sugar cane = 85 kg of sugar produced; Sugar price = Php. 900.00 for 50 kg.
Milling speed = 200 tons of sugar cane/hour makes approx. 17,000 kg of sugar per hour.
4.25% of 17,000 kg = 722.5 kg per hour loss.
722.5 kg at Php. 900 / 50 kg = Php. 13,005 per hour loss.
12 hours per day, 150 days per standard milling season = Php. 23,409,000 production loss per season.

Scenario B) Assuming that the operator chose to stop production and have the seal repaired.  The replacement takes 24 hours to undertake. Breakdown occurs three times per milling season. Therefore 72 hours of lost production per season.

One ton of sugar cane = 85 kg of sugar produced; Sugar price = Php. 900.00 for 50 kg.
Milling speed = 200 tons of sugar cane/hour makes approx. 17,000 kg of sugar per hour.
72 hours x 17,000 kg = 1,224,000 kg lost production per milling season = Php. 22,032,000

(3) Hydraulic Oil Cost Savings

Under Scenario A), the operator continues to allow hydraulic oil to leak until the next scheduled service, the resultant wastage amounts to several drums worth of lost oil and therefore prove very expensive. It was calculated that the loss of oil rate was around 2.5 ltr per hour of operation. As previously stated, the milling season is approx. 1,800 hours. Oil leaking rate = 20 liters / 8 hours = 2.5 liters / hour x 1800 hrs = 4,500 liters.

  • One hydraulic oil 210 ltr drum cost = Php. 15,000
  • Therefore, total savings per milling season is Php. 321,428 (Php. 15,000 x 4,500/ 210)
  • This does not take into account the additional process required to remove the leaked oil from the juice process

(4) Savings from Effective Extraction

Under Scenario A) or B), the inefficient performance of mill jack/cylinders results in poor extraction. This is because insufficient press loading from the leaking mill jack would not force the required and expected amount of juice to be extracted per sugarcane batch.

The very first repair done by Piesco Hydraulics was on the Mill Jack Cylinders (2 units) of the 4th roller of Tandem B. The 4th roller is critical as it does the final and finishing juice extraction operation.

Piesco Hydraulics improved the performance of 4th roller mill jacks which then resulted in efficient extraction. Because the improvement was recognized as substantial, they also assigned the repair of the remaining 1st, 2nd and 3rd roller to Piesco Hydraulics on the following years.

(5) Efficient extraction = Dry bagasse to feed the boiler

The efficient extraction of the juice from the sugar cane will leave behind dry bagasse.

Dry bagasse can be used as fuel to heat the boiler. If the bagasse is too wet (the juice is not entirely extracted), there are two possible actions:

  • subjecting the wet bagasse to a separate dewatering process, or
  • directly using the wet bagasse to heat the boiler and add bunker fuel for effective combustion.

The installation of another dewatering station and the use of more fuel for bunkers entail additional costs for the plant. For this reason, the bagasse must be already sufficiently dry as it passes through the last roller mill. Piesco has been able to improve the performance of its roller mills, and the resulting bagasse is already sufficiently dry as fuel. Therefore no further dewatering costs or fuel for bunkers are required.

Repair of other rollers

Given the remarkable improvement and cost-saving using Chesterton thermoset polyurethane seals distributed and installed by Piesco Hydraulics Philippines, the customer decided to handover the complete set of roller mills for future upgrades and on-going repair.

About Us


Chesterton® is a world leader in helping process industry companies and manufacturers improve the reliability and efficiency of their rotating, stationary, and fluid power equipment platforms. We are known across a wide range of industries for our award-winning pump and valve sealing solutions, applications expertise, equipment maintenance and wear-prevention products, and knowledgeable hands-on local service​.

Mentioned in the case study:

Maker of Quality & Upgraded Hydraulic and Pneumatic Cylinders.

® Registered trademark owned by A.W. Chesterton Company
Case Number APAC0002 – Issued 08/20

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