Rating Particle Filters

The international standard method for rating lube and hydraulic filters is the Multi-Pass Test [95]. As illustrated in Fig. 18.29, a slurry of silica particles is continuously fed into the test circuit. As particles flow into the filter under test, some are captured, and the remainder continues to recirculate. Throughout the

Table 18.5 Summary of recommended contamination control practices for wind turbines

Area

Description

Design

Materials

Component and subsystem cleanliness

Roll-off cleanliness

Transportation

On-site storage Prevent contaminant ingression Rapid contaminant removal Off-line contaminant removal

Drain oil from gears directly back into the sump, bypassing bearing packages. This allows filters to remove gear wear debris upstream of bearings. Use dynamic seals with minimal breathing Avoid brittle materials that can shed hard particles. Avoid copper containing alloys contacting lubricants Remove manufacturing swarf, grinding/polishing compounds, machine chips, airborne dirt. Avoids early damage leading to premature failures. See ISO 10949 Systems and replacement parts should be shipped in cleaner condition than operating systems Ship in sealed packaging to prevent ingression of airborne dust and water from rain and splashing Seal and store systems and replacement parts in protected enclosures Install regenerable breather dryers and/or pressured dry air blankets

Install 5 im full-flow (inline) particle filters

Install water removing cartridges offline; use dry air blanket systems as needed. If 5 im full-flow filters not available, supplement with 3 im offline filters

Fig. 18.28 Flowchart of a contamination control system

Fig. 18.28 Flowchart of a contamination control system

Fig. 18.29 Schematic of the multi-pass test for rating filter efficiency. A fine powder of contaminant, ISO medium test dust, is continuously fed into the system. Upstream and downstream particle counts taken during the test are used to calculated the beta value (bX(C)), as described in the text

Regenerabte Breather Dryer with 3 Micron Filter

Dry Air

System

Objectives: ISO 14/12/1(1 125 pp m ma\

Fig. 18.30 Detailed diagram of recommended filtration cycle for ingression prevention and removal. Main lubricant circuit on left, with 5 im (bs(C) C 1,000) installed. Side-loop (offline) circuit shown with optional 3 im (b3(C) C 1,000) particle filter and water absorbing cartridge. Also shown is optional dry air system for removing water from gear oil [96]

Regenerabte Breather Dryer with 3 Micron Filter

Dry Air

System

Objectives: ISO 14/12/1(1 125 pp m ma\

Fig. 18.30 Detailed diagram of recommended filtration cycle for ingression prevention and removal. Main lubricant circuit on left, with 5 im (bs(C) C 1,000) installed. Side-loop (offline) circuit shown with optional 3 im (b3(C) C 1,000) particle filter and water absorbing cartridge. Also shown is optional dry air system for removing water from gear oil [96]

test, the number of upstream and downstream particles is measured with electronic automatic particle counters. Filter efficiency for particle size X (in microns) is reported as the ratio of upstream to downstream counts recorded during the test. This measure of filter efficiency is termed the 'beta ratio', bX(c):

bX(c) = (Upstream Counts >X^m)^(Downstream Counts >X^m) (18.24)

Modern filter ratings are bX(c) C 200 and bX(c) C 1000. As an example, for a filter rated at b5(c) = 1,000, 1 out of every 1,000 particles equal to or greater than 5 im passed through the filter during the test, while the other 999 particles were captured by the filter.

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

Get My Free Ebook


Post a comment