- Ideal for lab environments
- Smaller than G-Cal devices
- More accurate than G-Cal devices
- Require a temperature-controlled environment
- Inexpensive calibration solution
Dynacal perm tubes and wafer permeation devices are small, inert capsules containing a pure chemical compound in a two phase equilibrium between its gas phase and its liquid or solid phase. At a constant temperature, the device emits the compound through its permeable portion at a constant rate.
Perm tubes and wafer devices are typically inserted into a carrier flow to generate test atmospheres for calibrating gas analyzer systems, testing hazardous gas alarms, or conducting long-term studies of effects on materials or biological systems – in short, any situation requiring a stable concentration of a specific trace chemical.
This is just a sample of what we offer. If you need something not on this list, contact Metronics.
| Chemical name | CAS |
|---|---|
| Acetaldehyde | 75-07-0 |
| Acetone | 67-64-1 |
| Ammonia | 7664-41-7 |
| Benzene | 71-43-2 |
| Carbon Disulfide | 75-15-0 |
| Carbonyl Sulfide | 463-58-1 |
| Chlorine | 7782-50-5 |
| Decane | 124-18-5 |
| Dichloromethane | 75-09-2 |
| Dimethyl Disulfide | 624-92-0 |
| Dimethyl Sulfide | 75-18-3 |
| Ethyl Mercaptan | 75-08-1 |
| Ethylene Oxide | 75-21-8 |
| Formaldehyde (para) | 30525-89-4 |
| Hydrogen Sulfide | 7783-06-4 |
| Hydrochloric acid(20.2%) | 7647-01-0 |
| Hydrogen Chloride | 7647-01-0 |
| Hydrogen Cyanide | 74-90-8 |
| Mercury | 7439-97-6 |
| Methyl Mercaptan | 74-93-1 |
| Nitrogen Dioxide | 10102-44-0 |
| n-Pentane | 109-66-0 |
| Sulfur Dioxide | 7446-09-5 |
| Toluene | 108-88-3 |
| Water | 7732-18-5 |
Perm tube
The perm tube, a sealed permeable cylinder containing the desired permeant reference material, is the most widely used of the various permeation devices. Release of the chemical occurs by permeation through the walls of the PTFE tube for the entire length between the impermeable plugs. A wide range of rates can be achieved by varying the length and thickness of the tube, with typical rates ranging from 5 ng/min to 50,000 ng/min.
Extended life perm tube
Our unique extended life (XLT) perm tube is essentially a perm tube coupled to an impermeable stainless steel reservoir. This design offers a range of permeation rates corresponding to a standard perm tube, but has a significantly enhanced lifetime – by a factor of 3 for a 5 cm (active length) device or a factor of 12 for a 1 cm device.
Wafer device
Wafer devices have only a small permeable window, or wafer, so permeation rates are typically lower than rates for perm tubes. Since permeation occurs only through the polymeric wafer, the permeation rate is controlled by varying the wafer material, the thickness of the wafer, and the diameter of the permeation opening. Gases whose high vapor pressure at normal permeation temperatures prevent their containment in a tubular device can be contained in a wafer device. Wafer devices are available in different styles to allow use in calibrators made by various manufacturers.
