Quick Jobo question

[2F/2F]

Hello,

How deep is the water bath in a Jobo processor?

Thanks in advance.

 

[jeroldharter]

There are two levels to the bath. The upper level where the drum goes is adjustable, depending on whether you use the expert drums (deeper) or the regular drums (shallower). All told it is maybe 1.5 inches max, typically about 1 inch.

 

[2F/2F]

Sorry for being too general, and thank you for the information.

I am talking about the upper bath with an Expert Drum. I am wondering how much of the drum is in water during the processing.

 

[bdial]

It really depends on how much water you put in the bath, the maximum would be about 2 inches of the drum's diameter.

 

[MikeSeb]

You didn't say which processor. In my ATL 1000/1500 the bath is maybe 4 inches deep; less than half the tank's diameter is immersed.

Off the top of my head--I can measure more precisely if needed.

 

[Oren Grad]

I am talking about the upper bath with an Expert Drum. I am wondering how much of the drum is in water during the processing.

The water level in the upper tray where the drum sits is adjustable, by changing the orientation of a widget that partially covers the outflow port.

In general, the idea is to have the water level just high enough so that the slots in the Expert drums pick up the tempered water and circulate it inside the drum, without putting more drag on the drum than is needed. Used optimally, very little of the drum is actually submerged.

EDIT: I should have added, the big paper drums like the 3062 and 3063 don't have slots. But even those, my recollection is that I have them submerged maybe half an inch or so when I run them. Again, not much at all.

 

[edtbjon]

It's important that the drum doesn't float on top of the water. It's just there to keep the temperature at the correct level. With the Expert drums the water does introduce quite a lot of extra drag, so especially if you are developing close to the actual room temperature (i.e. B/W), it's better to use less, like ½" or so. (While there is a lot of worry about the different series of motors, given proper care any of these motors should cope with amateur use for more or less a lifetime. But I recon it's good practice not to stress the motor unless you have to, like when you really do need to use a full litre of developer.)

MikeSeb, as 2F/2F uses Expert drums, it isn't an ATL 1X00, where the water level is controlled by the processor. (I recon it's the same for all the ATL machines.)

//Björn

 

[AgX]

This is the original Jobo Text:

How high do I set the water level in my JOBO rotary processor?

The water bath level is an important factor in getting the best results in JOBO rotary processing. Adjust the water level to about 1 cm [1.5cm in their German text] over the bottom edge of the tank or drum in use. This provides enough immersion to keep it at the correct processing temperature and is low enough to prevent the drum from floating. If the water level is too high, the end of the drum away from the motor will float and all the chemicals will stay at the low end, leaving part of the material either unprocessed or poorly processed. If you are using a lift, then the floating drum will put unnecessary strain on the rotation motor as the cog lid on the tank and the transfer gear on the lift are out of alignment and causing friction.

To adjust your water level, simply add or remove water from the water bath on DuoLab, CPE-2 or CPE-2 Plus processors. On the CPA-2, CPP-2 and AutoLab processors, adjust the water level control dial or sliding door to raise or lower the water level until it is correct. (The ATL-1000 is pre-set for the correct water level since only one series of tanks fits onto it.)
Remember too, you must adjust the supporting rollers to their correct position to help keep the tank or drum level. The tank or drum should always be resting on the rollers to maintain a level position. To check if the drum is floating, push down on it directly over the rollers. If you feel the drum move down, it was floating and the water level needs adjustment. If there is no movement, it was properly resting on the rollers.