Hydrothermal Cell User Guide
Contents
Components list
Component | Image |
---|---|
2.5 mm OD Fused Quartz Capillary | |
PTFE Ferrule | |
Blue Nut | |
Threaded Aluminium Block | |
Heat Transfer Block | |
Spacer Block | |
End Block | |
Alignment Jig | |
Front Plate | |
Hydrothermal Cell Top of cell (left) Bottom of cell (right) |
Sealing the capillary
Step | Description | Image |
---|---|---|
1 | Fill the capillary to the required level (generally between 1/4 < 1/3 < 1/2 full) using a syringe and needle. | |
2 | Place the ferrule over the open end of the capillary. | |
3 | Insert the capillary into the threaded aluminium block such that the flat end of the ferrule sits on the back face of the threaded hole. | |
4 | Place the threaded nut over the sealed end of the capillary and give it approximately 1/8 of a turn (so that the thread just starts to interlock and the nut is in contact with the ferrule, but you are not deforming the ferrule). | |
5 | Insert the sealed end of the capillary into the heat transfer block such that the largest end of the block is in contact with the blue nut. | |
6 | Take the alignment jig and make sure that the grub screws are undone enough so as not to obstruct the blocks. | |
7 | Insert the capillary assembly into the alignment jig such that the threaded block is on the side with the largest gap between the grub screws. The face with two chamfered edges should be facing down for both the threaded block and the heat transfer block. | |
8 | Whilst applying downward pressure onto the blocks to ensure that they are in contact with the base of the alignment jig, tighten the grub screw until they start to bite on the aluminium blocks. Over-tightening may result in the formation of burs that will obstruct the capillary assembly from slotting into the cell easily. If this occurs then sand down the blocks on a flat surface. | |
9 | You can now tighten the blue nut to compress the ferrule and seal the capillary. (The PTFE ferrules can be compressed more than you would initially think. Don't be afraid to tighten the nut. Listen carefully as you tighten to hear if the capillary cracks. | |
10 | Once Fully tightened you can undo the grub screws on the alignment jig to release the capillary assembly. |
Loading the cell (offline)
Step | Description | Image |
---|---|---|
1 | Position the cell so as it stands flat on the feet at the back of the cell. You may need to move the latch on the electrical connector so that it is out of the way. (NB the bottom of the cell is the end with the PEEK block, electrical connector and aluminium base-plate attached. | |
2 | Check that the 0.5 mm k type thermocouple is inserted through the PEEK grommet in the back of the cell. And is secured in place by washers on the back of the cell. | |
3 | Undo the alignment screws for the sample position so that there is plenty of room in the track to insert the aluminium blocks. | |
4 | Insert a spacer block at the bottom of the slot in the cell (chamfers facing down) | |
5 | Next insert the end block such that the drilled out dimple is facing towards the top of the cell. The end block should sit flush with the spacer block positioned in the previous step. (chamfers facing down) | |
6 | Position the 1 mm thermocouple through the top of the cell such that it lies along the corner of the slot in the cell. This should be inserted until the end of the thermocouple is in line with the centre of the threaded aluminium block when the capillary assembly is in place. | |
7 | Insert the capillary assembly (chamfers facing down) such that the flame sealed end of the capillary sits within the dimple of the end block. The heat transfer block should be flush with the blue nut and the bottom end should sit just above the hole in the back of the cell. The capillary should depress the 0.5 mm thermocouple such that the end of the thermocouple is in contact with the capillary and not in contact with the heat transfer block. The 1 mm thermocouple should be pinched in the corner of the slot between the cell body and the chamfer on the aluminium blocks. | |
8 | Insert another spacer block (optional and not necessarily possible) | |
9 | Whilst maintaining downward pressure on the aluminium blocks, tighten the alignment screw to hold everything in place. Don't over tighten the alignment screws as this causes unnecessary stress on the capillary and can cause the aluminium blocks to buckle upwards. | |
10 | Place the front plate onto the cell so that the apertures line up with the cut-outs in the cell and secure in place. | |
11 | Check the heat transfer block hasn't slipped out of place and that the thermocouple is still in contact with the capillary. |
Mounting the cell
- put on the beamline
Controller Power Supply Unit
Step | Description | Image |
---|---|---|
1 | Ensure the Ethernet port on the unit is connected to a valid Ethernet port in the hutch. Plug the unit in to the appropriate power supply for the required output power. Generally this will be mains voltage for the hydrothermal cell. | |
2 | Switch the unit on with the green on/off switch in the middle of the front panel. If the power supply is good then the orange light above and the green switch itself will illuminate. | |
3 | The controllers will do a self test on startup. Clear any expected Sensor break errors. If you are not expecting such errors then check the thermocouple are plugged in and operational. | |
4 | Connect the cell to the power unit via. the white Han A connector. | |
5 | When ready to start heating press the "Start Heating" button. This should engage the relays (you will hear a click) and the button should illuminate. | |
6 | When cooling the cell and before unplugging the cell (white Han A connector) it is good practice to disengage the relays. Press the "Start Heating" button to do this. | |
7 | Remember to plug in the cell, re-engage the relays and plug in the thermocouples before heating the cell again. |
EPICS interface
There are two options for how to run the controllers in EPICS. Either change the target setpoint (SP) on the fly or set up a program and run it remotely. EPICS PVs can be set from GDA (see staff page for more details).
Direct Control Through EPICS
Step | Description | Image |
---|---|---|
1 | On the beamline synoptic, click the JSAM button (4th component from the right) | |
2 | There are two Eurotherm 3504 controllers listed in the bottom right corner of the sample stage. "Eurotherm 3504 -1" and "Eurotherm 3504-2" correspond to the left and right hand controllers in the power supply unit, respectively. | |
3 | Each controller can control two loops. At this point the hydrothermal cell only uses one heating loop. Ensure that the button in the top right hand corner for the heating loop (generally loop 1) is switched to "ON". Set the Setpoint to a value around room temperature. Press enter for the change to be accepted and check if the green value to the right gets updated. If not then there may be a problem with communication to the device. Ensure the controller is switched on and that the button in the top right corner reads "ON". Check that the Ethernet port is functional. Select an appropriate Ramprate. (The GUI reads C/s as units but this is actually °C min-1) Change the Manual mode option from "Manual" to "Automatic". This will allow the controller to modify the output power to maintain the setpoint. The Output can be left at 0 when in automatic mode. If in manual mode then the output power can be changed manually. This is sometimes useful for cooling the cell, but remember to change the mode back to automatic before heating the cell again. The green value to the right will update as the controller increases/decreases the power output. The Temp value is the read-back from the control thermocouple (1 mm K-type in the top of the cell) The PID values can be modified and tailored to the experiment. The Temp value on Loop 2 is generally set up to be the read-back from the 0.5 mm K-type thermocouple in contact with the sample. | |
4 | Do final checks to ensure that the relays on the controller power supply unit are engaged and that the cell is plugged in. The fan should be turned off so as not to actively cool the cell. | |
5 | Start a data collection. Once you have enough data points at ambient temperature change the Setpoint to the required temperature. Do not exceed the temperature previously agreed with the beamline staff for the PID values being used. If the cell doesn't start to heat check the following;
|
Start Program Remotely
Open the temperature control panel as described in the previous section.
Step | Description | Image |
---|---|---|
1 | Open the temperature control panel as described in the previous section. | |
2 | Click the Programmer button in the bottom left corner. | |
3 | Enter the program number that you want to run | |
4 | Click "Run" to start the program and "Reset" to stop it. |
Unloading the cell (offline)
- Lie the cell flat on its back.
- undo the nuts holder the front-plate in place.
- Slacken off the alignment screws.
- remove the capillary assembly.
- Undo the blue nut and remove the capillary from the threaded block. (the ferrule can be very tightly attached to the nut at this point so try to rotate the ferrule to break the seal (you may need pliers or grips).
- Dispose of the capillary with ferrule attached in the sharps bin
Pre-scan Checklist
Before closing up
- Blue "Start Heating" button on.
- Green lights on relays in back of power unit on.
- No sensor break errors and temperature readback giving realistic values.
- Power supply connected to cell
When Heating
- mode = automatic
- setpoint changed
- communication to controller on
When cooling
- setpoint low
- mode = manual
- output = 0