Category: Sample Filters
Product Code: Filters for Diesel Engine Analyzers
Totally inorganic filter cartridge is inert and contains no extractables
Temperature capability to 450°F (232°C)
Filter housing designed for convenient external heating
The Problem:
Diesel engine exhaust has a much higher concentration of suspended solid particles and nonvolatile liquid droplets.
Diesel engine exhaust has a high dew point and mustbe kept hot to prevent liquid condensation which would affect the accuracy of the analysis. To avoid contamination of sample lines with dirt and oil, most diesel engine analysis systems are designed with the primary filter close to the inlet of the sample system. The filter is externally heated to prevent liquid condensation when the system is started up, but during prolonged operation, the filter often is subjected to engine exhaust gas temperatures, which normally range from 350°F to 450°F (176°C to 232°C) and occasionally get as high as 600°F (315°C).
The Solution:
Model 38 filters, designed specifically for diesel engine exhaust, are all-stainless steel housings with silicone seals (maximum temperature 600°F/315°C). The 1/4” NPT inlet and outlet ports are located at one end of the cylindrical body, and the bayonet closure for changing the filter cartridge is located at the opposite end. To maintain constant temperature, the body may be wrapped in heating tape or enclosed in an oven. The novel closure design permits an operator wearing gloves to replace a filter element rapidly, without disturbing the heating provisions or gas flow connections. The filter housing may be oriented horizontally, vertically, or at any other convenient attitude.
The standard size Model 38/25 housing has a 10-inch (25 cm) long body. Where the installation requires a smaller size housing, the Model 38/12 with 5 1/2 inch (14 cm) long body is available.
The Grade DH21 filter cartridge, composed of borosilicate glass microfibers and inorganic binder, is inert to all components in the gas and stable to 900°F (482°C). The retention efficiency is 93% of 0.1 micron particles and 100% of 2 micron and larger particles. With flow direction through the filter tube inside-to-outside, the internal prefilter in the Grade DH21 cartridge provides satisfactory life in a relatively dirty environment. Since the dirt is trapped on the inside of the cartridge, the external surface of the cartridge and the filter housing remain free of contaminants.