The Difference Between Orkot® TLMM and TXMM

The hydro and marine industries rely on equipment, replacement parts, and materials that hold up to the enormous forces applied during the job. Orkot® products, made of a remarkable composite polymer, are extremely durable and provide these desirable qualities:

• Low level of friction production
• High tolerance to edge loading
• Outstanding wear resistance
• Tolerates freeze fitting without fear of shattering
• High tolerance to misalignment
• Negligible swelling in water makes for dimensional stability

Orkot® has two grades available for hydro applications: TLMM and TXMM. They are similar but with slight differences, potentially making one more appropriate for your project than the other. Read on to learn more about the specific qualities inherent in Orkot® TLMM and TXMM.

Orkot® TLMM vs. TXMM Properties

During the Orkot® manufacturing process, Orkot® TLMM incorporates solid lubricants in its reinforced, advanced polymer material. Orkot® TXMM begins the same as Orkot® TLMM in production but adds a specialized layer of PTFE that is several millimeters thick.

Polytetrafluoroethylene (PTFE) is a versatile, high-performance fluoropolymer. The layer of PTFE in the Orkot® TXMM offers a diminished friction rate and allows for running in dry applications as well as wet.

Sometimes referred to as synthetic polymer alloy, Orkot® TXMM’s advanced medium weave polymer material concentrates PTFE in the sliding areas, which maintains high compressive strength. It is tolerant of wear and maintains its 0.05% low friction properties for the duration of the bearing’s service life. The Orkot® TLMM friction rate of 0.13% is very low but not as low as materials reinforced with the PTFE layer.

Orkot® TLMM backs up the PTFE layer to make the TXMM bearing material homogeneous without a layer of metal backing it. The lack of metal backing makes Orkot® TXMM especially effective when running conditions are dry, having proven proficient in eliminating stick and slip problems.

Orkot® TLMM vs. TXMM Application

When determining which grade of Orkot® to use, keep in mind these typical uses:

• Orkot® TXMM is typically the product of choice when dry operating applications exist.
• Orkot® TLMM is generally the best product for use with fully submerged water applications.

Extensive testing has shown Orkot® TXMM’s wear resistance properties are slightly superior to Orkot® TLMM. Testing on Orkot® TXMM bearings included velocities down to 5 meters/16 feet per minute, pressures of 6 bar/87 psi, and water flows down to 2 liters/4 pints per minute. The bearing operated for 2,000 hours on an LG4 Bronze sleeve with seawater containing silica flour (250 ppm) and 200mm/8-inch bearing. The results per 1,000 hours show overall wear on the bearing at 0.027mm/0.001 inch.

Both Orkot® TLMM and the Orkot® TXMM are suitable for use in bushings, wear pads, and thrust washers. It is common among project scopes to request “Orkot® or equivalent.” The explanation for this is simple — Orkot® set the standard, which is recognized across the industry.

Orkot® TXMM material has undergone extensive testing by Powertech labs and was one of the first to earn approval from Powertech. It has also been approved for use in Hydro applications by the US Army Corps of Engineers. 

When selecting the best product for your needs, compare the application properties with the service requirements of the project you’re considering. 

Orkot® Hydropower Project

The Carillon Power Station is a “run-of-river” power plant on the Ottawa River. With fourteen generating units supplying power for 150,000 households and a total capacity of 753MW, it is the most powerful hydroelectric station on the river. 

All of Carillon’s fourteen 54-MW turbine generator units are getting refurbished in a project that will take 16 years to complete. The first phase will refurbish six units with new speed governors, generators, and turbines. It was 1960 when the original units were commissioned, which included the "Standard Bronze" greased bearing materials used extensively at the time.

For the refurbishment, CRC Distribution supplied Orkot® greaseless bearings for all six turbines, along with two complete sets of spares. For the “Trial Fit Test,” Orkot® bushings were freeze fitted into dummy housings and proved that Orkot® installed clearances would be as specified.

Orkot® for Hydro and Marine Industries

Mission-critical industries like hydro and marine require top-quality supplies and materials to maintain their vital roles in the world’s power supply and global economies. Two of the most advanced grades of reinforced polymer materials available are Orkot® TLMM and TXMM, which offer unparalleled performance and reliability that reduce downtime and maintenance. Especially for hydropower applications where greased bronze bearings are typical of older facilities, Orkot® significantly outperforms greased bronze. See the comparison during a two year study where both materials were placed on a 300MW turbine at Dinorwig Power Station.

Is Orkot® a good fit for your next project? Contact CRC Distribution to speak with one of our Orkot® experts who can provide more information and a free quote.