drastic temperature differences between technotrans and water pans

[Albert Noel]

any ideas as to what would cause a large difference in temperature between the technotrans unit and the water pans in the press? also, a large difference in temperature between waterpans at each unit?

the technotrans itself is set for 10.5c and should therefore be about 11.5c when it enters the press. i'm seeing temps at around 16c at one pan and even odder, is two units over, the lowest temp in the pan is as high a temp as 19c .

as far as i know, theres no issues with insulation and i'm sure the chiller is working properly.

how is it possible that theres a 9-10 degree difference between the tank and the pans?

 

[Slagneb]

The further the water has to travel can cause it to be warmer at the pans. Also some lines may pass pumps or motors that give off warmth or may keep the lines constantly warm?

Hope this may help.

 

[Albert Noel]

The further the water has to travel can cause it to be warmer at the pans. Also some lines may pass pumps or motors that give off warmth or may keep the lines constantly warm?

Hope this may help.

well, i know how the whole thing works. the reason it's so strange to me, is that pans that are closer to the chiller are warmer than the pans that are farther away.

i know it has the possibility of being close to somehting thats giving off alot of heat, but being insulated and still loosing 10 degrees seems a little extreme to me.

 

[Deleted member 16349]

well, i know how the whole thing works. the reason it's so strange to me, is that pans that are closer to the chiller are warmer than the pans that are farther away.

i know it has the possibility of being close to somehting thats giving off alot of heat, but being insulated and still loosing 10 degrees seems a little extreme to me.

Albert, I am assuming that these temperature differences are being measured when the press is running or very shortly after it stops. There is a lot of heat build up in rollers. Actually when you are running and if you measure the temperature of the rubber roller surface with an infrared thermometer, the temperature will not be so hot but when you stop, the temperature will rise. There is a heat build up in rubber due to the continual flexing. The surface of the roller gets cooled by the fountain solution being cooler and also due to its evaporation. But when the press stops, the heat build up in the roller shows up as an increase in the surface temperature of the rubber, since there is nothing to cool it at that time.

A lot of the energy to run a press is used for the continual flexing of the rubber on the rollers and that all goes to heat.

If the pans are at a different temperature after the press has stopped for a long time, then that is a different situation and I have no idea about that.

 

[Albert Noel]

the temps were measured with a laser thermomiter at each pan while at rest (the press was just done running 40,000 sheets about 35mins before the measurement was taken.


i just assumed they should be a little more consistant and closer together.

 

[Deleted member 16349]

the temps were measured with a laser thermomiter at each pan while at rest (the press was just done running 40,000 sheets about 35mins before the measurement was taken.


i just assumed they should be a little more consistant and closer together.

I would expect that the temperatures of the pans would become closer and colder the longer the press sits idle.

This brings up an interesting point. With this situation it means that when starting up the press, after it has been stopped for a while, the initial temperature conditions will be colder and then the press will get a bit warmer after running. I am guessing this will have some affect on the density stability. That would be avoided with positive ink feed, since it is independent also of temperature changes in the roller train.

 

[madjock]

Have you tried increasing the flow to and from the water pans?

 

[Albert Noel]

i haven't done that yet as it's been the same for the last 8 or 9 years and it hasnt been an issue. i suppose i can try that.

 

[Pressmanscooter]

I've tried to measure my pan temp with an infrared thermometer and found it to be far less than accurate. Try verifying these temperatures with an actual bimetal or digital thermometer. Your pre-press department might have a thermometer from an old processor or something.

 

[Albert Noel]

we were talking about this when the other guy was doing the measuring. i might try this, i was thinking at the time that the thermomiter was actually reading the pan temp not the water temp, but my opinion was quickly hushed .

I've tried to measure my pan temp with an infrared thermometer and found it to be far less than accurate. Try verifying these temperatures with an actual bimetal or digital thermometer. Your pre-press department might have a thermometer from an old processor or something.

 

[Pressmanscooter]

Infrared temp guns are great tools but there not very useful when measuring liquids, at least shallow fluids in stainless steel pans.

 

[Paultheprinter]

temp issues

temp issues

hi there,

just visited the website and found your question, sorry if i repeat any of the previous answers but i run a sm 74-5 and have checked the temp on a few speedmasters both 74 and 102. To see such a large difference is obviously a concern to you as it would be to most printers, on my technotrans unit the temp is taken from the return from the heat exchanger unit and not from the main fount bowl in the unit, this can cause a difference of 1 to 2 degrees c, from there on my speedmaster the fount is distributed into three pipes units one and two, unit three and last four and five. If i read the temp with a ecs/tds/ph temp meter the bowl reads 10 degrees the units read from 11 to 13 degrees all this with the temp reading 9 degrees at the unit, so there is a large ammount of error naturally. As for the flow this could cause the issues but on my unit the flow is controlled from a dial which should be set at 0.7 bar but i see no major temp difference with the flow at 0.4 to 1.1 bar. I think the issue is as previousley stated with the ir thermometer to measure liquids, when i use my ir i measure the chrome metering roller insted and see how this compares to the rest of the units. Hope this helps

Paul

 

[Albert Noel]

i tried increasing the flow rate both too and from the pans, with no real difference noted.
i'm starting to think that maybe the coolent in the chiller is just toast and neds to be replaced. 8 years of 24/5 use must take it's toll.

i'm going to pick up a better thermometer this weekend to reemeasure.

 

[Paultheprinter]

hi again,

if your gas in the technotrans wasnt chilling very efficiently you would probaly over heat the condensor and cause it to trip, thats what happens on mine

paul

 

[printr640]

What would be optimal water temp. I'm running at 55 degrees, measured in water tanks.

 

[potus]

i tried increasing the flow rate both too and from the pans, with no real difference noted.
i'm starting to think that maybe the coolent in the chiller is just toast and neds to be replaced. 8 years of 24/5 use must take it's toll.

i'm going to pick up a better thermometer this weekend to reemeasure.

if the technotrans maintains its set temp while on long print run don't worry about the refridgerent.
i'm surprised you've seen no diff' when increasing the flows, i'd have this down as suspect number one, so long as hoses are well insulated, reserve judgement until you get a new temp' gauge.