Field Engineering Bulletin Bulletin No. 40.20.58 SundGard Desiccant Breathers EFFECTIVE DATE: NOVEMBER 2014 REV: ORIG AFFECTED MODELS: LMX-31X, 33X, 34X PAGE 1 OF 8 Note: Not applicable for ATEX zone 1 or 2 units until further notice Gearbox Breather Basics The purpose of the breather is to allow for intake and exhaust stroking of the internal gearbox atmosphere with the outside environment. As the internal gearbox temperature increases, the pressure increases, which produces an exhaust stroke of air through the breather and into the outside environment. As the internal gearbox temperature decreases, a slight vacuum is created, which produces an intake stroke of air from the outside environment through the breather and into the gearbox. The intake stroke must be adequately filtered to scrub the incoming air of moisture and particulate matter to protect the internal gearbox lubricant from contamination and to prevent part corrosion. Contamination and Corrosion Environments with a high percentage of humidity, frequent temperature changes, or local wash down activities will increase air moisture content. Without adequate moisture scrubbing ability, the gearbox internal lubricant will become infused with water. Corrosion from rust formation and damage from reduced oil viscosity will occur. Environments with particulate matter, debris, or dirt will contaminate the air. Without adequate particle scrubbing ability, the gearbox internal lubricant will become dirtier, which diminishes oil filtration capability and accelerates the generation of new contaminants, leading to oxidation. Product Improvement In an effort to provide the best possible internal gearbox air quality, two new and different desiccant breathers have been made available. The desiccant design incorporates moisture absorbing silica-gel media and particulate filtering polyester elements. Additionally, check valves located at the base of the breather allow air exchange only when necessary (during a pressure/temperature change) to extend the life of the breather.
Bulletin No. 40.20.58 Page 2 of 8 New Sundyne Breathers P/N 25-007: Standard equipment breather to be implemented on new and exchange 31X/33X/34X gearboxes. Replaces breather P/N 25-003. For applications requiring a steel constructed breather, the 25-003 will remain a purchasable part. The 25-007 has been specifically engineered to provide a robust connection to the Sundyne gearbox. Unlike conventional aftermarket desiccant breathers, the 25-007 features a steel adapter fitting that threads into the base of the breather. The design allows the adapter fitting to engage the internal section of the breather for added connection strength. Industrial applications require reliable and strong auxiliary components; the 25-007 offers a distinct strength advantage over breathers that utilize a plastic connection fitting. O-RING Carbon Steel, Zinc plated adapter fitting for rust protection Fluorocarbon o-ring material
Bulletin No. 40.20.58 Page 3 of 8 The 25-007 has one intake and one exhaust check valve located at the base of the breather. The check valves allow the breather to be sealed-off from the environment when no air exchange is necessary. The additional protection keeps debris, particulate matter, and humidity from reducing the life of the desiccant media. The check valves reside in a chamber located within the interior of the outside shell near the fitting attachment point. CHECK VALVE HOUSING AREA - CHAMBER EXHAUST CHECK VALVE INTAKE CHECK VALVE HOUSING AREA OPENING(S) The 25-007 breather is shipped with three protective dust/debris covers that will need to be removed before installation: 1 3 REMOVE 2
Bulletin No. 40.20.58 Page 4 of 8 P/N 25-008: Upgrade breather for heavy duty applications requiring increased desiccant media life expectancy, greater exterior shell strength, and larger internal filter elements to protect against oil misting to the atmosphere. Fits 31X/33X/34X with additional fitting P/N 19-1500. BREATHER ATTACHMENT 1-1/2 x 16 UN MALE THREAD FLUOROCARBON O-RING 19-1500 GEARBOX ATTACHMENT 3/4 NPT MALE THREAD Carbon Steel, Zinc plated material for rust protection Fluorocarbon o-ring material
Bulletin No. 40.20.58 Page 5 of 8 The 25-008 has two intake and two exhaust check valves located flush at the base of the breather near the fitting attachment point. INTAKE CHECK VALVE EXHAUST CHECK VALVE EXHAUST CHECK VALVE INTAKE CHECK VALVE The check valves utilize orange-red diaphragm assemblies as shown above. The diaphragms should not be mistaken for shipping plugs. The diaphragms are a working part of the breather and should not be removed. The 25-008 breather is shipped with one protective dust/debris cover that will need to be removed before installation: REMOVE 1
Bulletin No. 40.20.58 Page 6 of 8 The 19-1500 adapter is shipped with two protective dust/debris covers that will need to be removed before installation: 1 REMOVE 2 Desiccant Media The silica-gel media changes color as it absorbs moisture: Orange color = new or 100% moisture absorption capacity (full life) Light orange to white color = working as intended with remaining moisture absorbing ability (replacement breather should be stocked / inventoried) White color = completely used or 0% moisture absorption capacity (no life, replace) The orange colored media slowly changes to white over a time period unique to the local environment and conditions. High humidity environments will produce faster media color change (shorter breather life due to more moisture) than dry humidity environments. The breather is disposable and should be replaced when the media is mostly white in color. The following pictures illustrates the media color difference: Continued.
Bulletin No. 40.20.58 Page 7 of 8 DARK ORANGE COLORED MEDIA WHITE COLORED MEDIA NEW 100% ABSORPTION ABILITY COMPLETELY USED 0% ABSORPTION ABILITY REPLACE Specifications PART NUMBER 25-007 25-008 DESCRIPTION Standard Desiccant Upgrade Desiccant MODEL APPLICATION 31X, 33X, 34X 31X, 33X, 34X UNIT HEIGHT 5.31-inches (135 mm) 6.51-inches (165.4 mm) UNIT DIAMETER 2.52-inches (64 mm) 5.1-inches (129.5 mm) AMOUNT OF DESICCANT.28-pounds (125.1 grams) 1.75-pounds (793.8 grams) MAX ABSORBTION CAPACITY 1.68 fl-oz. (49.6 ml) 10.65 fl-oz. (315 ml) MAX FLOW RATE 1.45 cfm @ 1-psid 16 cfm @ 1-psid HYDROPHILIC AGENT Silica-gel Silica-gel BODY MATERIAL Polycarbonate Polycarbonate CHECK VALVE OPENING.12-psid.12-psid PARTICLE FILTRATION 3µ / Beta ratio = B3 200 3µ / Beta ratio = B3 200 ATTACHMENT FITTING Included, ¾-NPT connection Not included, requires P/N 19-1500
Bulletin No. 40.20.58 Page 8 of 8 Performance Lab tests were performed on a dedicated test rig designed to measure the amount of humidity scrubbing ability of each desiccant breather model. Subject to 100% humidity at 70 F ambient temperature, the breathers were able to reduce the humidity by 80 to 85%, proving that the desiccant design absorbs moisture. PLENUM BOX CONTAINING BREATHER AND 100% HUMIDITY (SATURATED AIR) GEARBOX INTERNAL ATMOSPHERE HUMIDITY % TEST LAB LOCAL ENVIRONMENT HUMIDITY % The difference between the test lab and the internal gearbox humidity percentage illustrates the effective amount of humidity allowed to enter the gearbox. Installation Note As an aftermarket item, each breather ships with protective plastic plugs. Breather P/N 25-007 has three plugs that need to be removed before installation. Breather P/N 25-008 has one plug and attachment fitting P/N 19-1500 has two plugs to remove before installation.