Low Lubricity

UNCD Components


UNCD® Powers Through Low-Lubricity Conditions:

One of the most common high wear applications for mechanical seals is pumping media with low-lubricity characteristics such as: hot water, light hydrocarbons, fluids with entrained gases. UNCD coated faces perform substantially better than conventional alternatives.

Test Results – Hot Water

UNCD faces exhibited almost no wear after 100 hours of severe service. In the same conditions, SiC faces exhibited extreme wear (well over 4,000 microinches of grooving) and seal leakage after 50-75 hours of operation. (250oF/121oC water at 100psig; ANSI pump; Multi-spring pusher seals).

Test Results – Entrained Gas

Diamond combinations ran an average of 67oF/37oC cooler than SiC/SiC pairings and exhibited substantially lower wear.

ATTRIBUTE SiC vs SiC SiC vs UNCD WC vs UNCD UNCD vs UNCD
Test Duration 1.5 hrs 100 hrs 100 hrs 100 hrs
Seal Face Wear 906 μin 342 μin 30 μin None
Avg. Temperature 140oF (60oC) 70oF (21.1oC) 69oF (20.6oC) 81oF (27.2oC)
Theoretical Wear Life 1.5 hrs 4.2 years 47.6 years Infinite

UNCD Performs During Pump Start-Up and Intermittent Dry Running

ADT has specifically designed UNCD to perform in intermittent dry running conditions. While absolute run times depend on a given set of conditions, the data shown on the right replicates typical severe conditions. UNCD tested in customer trials showed up to 20 times longer MTBF

Test Results – Dry Running

In dry running cycle testing UNCD running against a SiC counterface continues to successfully seal after having been exposed to 35 dry running cycles of 5 minutes each. SiC running against a SiC counterface fails consistently after the first 90 seconds of dry running.

North American Rail relies on UNCD

Objective: Major diesel engine supplier needed a solution for critical water pump seal failures.

Application: Locomotives can start un-attended without water. “Dry-Running” at start-up destroyed conventional seals within minutes – stranding units and leading to substantial operational issues.

Results: UNCD coated seals were installed and annual seal failures were reduced from 50 to 0; Operational and maintenance savings are estimated at more than $30M annually; 7,000+ engines in service without a dry-run failure