100-plus seals in tile making machines
Hydraulic systems used in tile making equipment require seals that are strong and wear-resistant to be able to handle pressure and temperature. Trelleborg Sealing Solutions supplies 100-plus seals for each ceramic press manufactured by Foshan Henglitai Machinery.
Ceramic tiles have been produced in the city of Foshan in Guangdong Province, China, for thousands of years, but the process has inevitably undergone huge changes since those first handmade examples.
Today’s tiles are mass-produced by machines that can measure up to 33 ft high/10 m high and 13 ft / 4 m wide, exerting a force of thousands of tons. Pistons and hydraulics systems lay at the heart of this equipment, and Trelleborg Sealing Solutions provides the seals that ensure their smooth, efficient operation for hours on end, all year round.
Seals are critical components in tile making equipment
“Our seals are critical components for these machines,” says Elton He, Application Engineer with Trelleborg Sealing Solutions in southern China. “We supply all the seals used in the cylinders, and since these provide the power used to press the tiles, they are of crucial importance to the functioning of these machines.”
Tiles are produced by pressing a powder consisting mainly of clay and feldspar into a mold using a piston. Then, another piston pushes the tiles out of the mold and away for drying, glazing and firing in a kiln.
Image shows a ceremic press from HLT
Today, Trelleborg Sealing Solutions provides the seals for a large proportion of the ceramic presses built in China and supplies all of China’s main ceramic press manufacturers. The largest of these is Foshan Henglitai Machinery (HLT), which was established in 1957 and produced China’s first hydraulic ceramic press in 1988. The company currently has the largest market share and exports to numerous countries.
Continuously withstanding very tough operating conditions
HLT’s biggest ceramic press exerts a maximum pressing force of 72,000 kN and contains between 100 and 150 Trelleborg Sealing Solutions seals, ranging in size from just 2 inches/ 50 mm to 5 feet 3 inches/ 1.6 m. These include many high-performance Turcon® based PTFE seals – engineered thermoplastic compounds that offer very low friction to reduce power loss and minimize wear over a long life. Orkot® wear rings are also used, which are composite bearing materials that incorporate advanced polymer technologies.
High-tech materials such as these are crucial for the demanding conditions under which they must perform. “Most of the cylinders move at a rate of about ten or 15 cycles per minute and the machines normally operate about 20 hours a day,” says Elton He. “They might only be shut down at the end of the year to perform maintenance, so these are very tough operating conditions.”
Image is a 3D cut out of a cylinder from a HLT ceramic press showing one of the sealing configurations.
Strong seals for high pressures
There are 100-plus seals from Trelleborg Sealing Solutions in each of Chinese ceramic manufacturer Foshan Henglitai Machinery’s ceramic presses. These can be divided into four basic types:
- Piston seals, such as those installed on the groove of the pistons that press the actual tiles
- Turcon® seals, such as patented Glyd Ring® T, Stepseal® 2K and Excluder®
- Orkot® and Turcite® Wear Rings
- Large-diameter O-Rings, which function as static seals on all the cylinders and flanges in the ceramic press
The seals have to be durable – sealing in the mineral oil-based hydraulic oil – as well as strong, wear-resistant and capable of handling pressures up to 35 MPa / 5,075 psi and withstanding temperatures in the range of 60°C to 80°C / 140°F to 176°F.
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