This post is also available in: Japanese
*This article was released in “Technical Journal No.79 published in June, 2015”
3.4 Sniffer units
The “HELIOT 900 series” has two types of sniffer units as shown below (Figure 6).
Unit A: Probe type with a capillary tube installed at the tip
Unit B: A booster pump unit with a small built-in pump installed onto the main unit’s test port along with a micro separator
The following points were taken into account when these sniffer units were developed.
Every leak test site is different. In order to design a durable sniffer unit, many potential problems need to be considered. For example, measures against clogging of capillary tubes due to foreign matter taken in from near the DUTs and malfunctioning of the equipment due to foreign matter that has gotten into the components of the main units (turbo molecular pumps and seals of various test valves) as well as physical damage to the sniffer
probes caused by mishandling.
For the “HELIOT 900’s” sniffer probes, sintered metal elements are used at the beginning of the capillary tubes, which are key components for taking in the test gas, in order to protect the capillar y tubes by physically eliminating the risk of foreign matter larger than the inner diameter of the capillary tubes from being taken in. Also, the elements are fixed to the inside of the probes, which reduces the risk of the elements coming off.
In addition, the material of the handles has been changed from plastic to metal, so the probes are better able to endure falls during leak tests.
The capillary tubes are installed at the tips of probes, which means they are as close to the sampling targets as possible, which improves the response by 10 to 20％ compared to the existing models (Unit A).
In addition, the ultimate pressure of the booster pumps used for Unit B is lower and the flow characteristics are superior compared to the existing models.
The weights of the sniffer probes and hoses have been reduced, so they are easier to handle. Once the booster pump units are connected to the main units’ connectors, they will automatically start operating and the main units will start up in leak test mode with the booster pump units recognized.
3.5 Cases and mobile carts
The standard design of the Components Division was adopted and the weight of the W1 type was reduced by 10 kg compared to the existing models. Users used to have to prepare vent por t joints, but now they are provided on the connector panels. The air-cooling fans have filters to prevent fine dust and dirt from getting inside. In addition, the ability to cool the inside has been enhanced to ensure that the units operate at maximum performance and remain reliable in Southeast Asia and other areas where the temperature is rather high.
The mobile carts have large casters, spaces that users can step on to raise the front wheels when going over steps between floors of different heights, foot brakes, and panel covers without projections or depressions, all of which make it easy to move the detectors. The carts also have spaces for storing the tablets before moving the detectors.