|
SAES Getters DF Tablets offer a package that allows easy mounting of the getter in a lamp. The configuration maximizes the exposed surface of the getter material. The presence of the metal tab allows easy mounting and welding of the getter into the lamp jacket. The extremely high dimensional reliability makes the DF ideal for use in high-speed automatic feeding systems. The volume of the getter assures a large sorption capacity; at the same time porosity of the getter body allows high sorption speed due to the increased value of the actual active surface.
 |
 |
|
Code |
Description |
Exposed Active Surface (mm2) |
Nominal Alloy Content (mg) |
Nominal Dimensions |
Standard Packing (pieces/can) |
|
|
|
|
|
A |
B |
h |
|
|
5F0015 |
St101/DF/25 |
25 |
50 |
8 |
5.6 |
1 |
12000 |
|
5F0020 |
St101/DF/50 |
50 |
75 |
10 |
7.1 |
1 |
7000 |
|
5F0512 |
St101-198/DF/25 |
25 |
60 |
8 |
5.6 |
1 |
12000 |
|
5F0513 |
St101-198/DF/50 |
50 |
90 |
10 |
7.1 |
1 |
7000 |
|
5F0509 |
St198/DF/25 |
25 |
70 |
8 |
5.6 |
1 |
12000 |
|
5F0508 |
St198/DF/50 |
50 |
105 |
10 |
7.1 |
1 |
7000 |
|
5F1300 |
St787/DF/25 |
25 |
70 |
8 |
5.6 |
1 |
12000 |
|
5F1301 |
St787/DF/50 |
50 |
105 |
10 |
7.1 |
1 |
7000 |
Mounting
The getter must be mounted in the jacket of a lamp in a position where, during the lamp operation, reaches a temperature within the recommended range for the specific alloy. It is common to mount the getter close to one of the ends of the arc tube. The getter starts adsorbing impurities after short time after the lamp switch on.
The DF getters can be used in lamps with jacket under vacuum, under nitrogen and under inert gas.
Operational temperature for DF Tablets:
|
St101 |
St101-198 |
St198 |
St787 |
|
350-400°C |
300-350°C |
300-350°C |
300-350°C |
If the jacket of the lamp is under vacuum or noble gases, the upper limit of the temperature range can be increased of about 50°C.
Activation
Activation parameters of the four alloys are shown below. A specific activation step is possible after the exhaust only in case of lamps with jackets under vacuum. This may be useful if it is necessary to improve the vacuum level in the jacket before the lamp switch on.
Activation for DF Tablets:
|
St101 |
St101-198 |
St198 |
St787 |
|
900°C for 30 seconds |
|
|
700°C for 20-30 sec. |
|
800°C for 5 minutes |
800°C for 3-5 minutes |
500°C for 10 minutes |
500°C for 10 minutes |
|
750°C for 25-30 min. |
|
|
350°C for two hours |
The Alloys
St101
St101 is SAES Getters’ Zr-Al alloy that is used in high temperature applications and if it is necessary that the getter does not operate during the manufacturing process.
St198
St198, SAES Getters’ Zr-Fe alloy that was made into DF tablets to offer a getter for lamps with lower activation and working temperatures than St101. Its hydrogen sorption is not as efficient as that of St101.
St101-198
St101-198 is a 1:1 mixture of the two alloys which attempts to capture the best qualities of each alloy—the low activation temperature of St198 and the high hydrogen sorption of St101.
St787
SAES Getters’ newest alloy for HID lamps, St787 is a Zr-Co-Rare Earth alloy that activates at low temperature. St787 has several advantages over the other alloys. St787 has much greater hydrogen sorption than all the other alloys, and sorbs CO about as well as St101.
Thus, St787 offers the best performance combination for activation and working temperatures and hydrogen sorption capacity.
|