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Re: Dp cooling
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?Hello Vladimir, I am all right! Hope you too! Well the things goes well here. Few weeks ago I just installed a new DP in my system. This is a VHS-4 from Varian. I was expecting better pumping speed, because the VHS-4 is capable up to 1200 L/sec. But some way that was not so enomorus change. The manufacturer advice for the inlet water temperature 15-20 celsius and for the outlet maximum 49 celsius at 0.15 gpm flow. So my DP is cooler than this. One more interesting phenomenon was, I used Santovac 5 in this DP, but that was no difference between the performance when the Apiezon AP201 was in the pump.With the AP oil the pumping speed was better! Actually I checked at the bottom the boiler temperature. Using Santovac 5 that was 215 celsius, using AP201 that was 170 celsius. The latter is good for that fluid, but the 215 celsius is too low for the Santovac 5. I dismantled the DP and I recognised the uppermost top jet was dry no oil on the inner surface, and the second from the top was same. So I guess the pump was not enough hot. Later I red that the VHS-4 was designed for silicon oils. So I decided to buy DC704 or equvivalent oil, and put a regulation valve in the feeder water line and a flow meter in the return water line. and just adjust the flow and than check the outlet temperature of the water not let hotter than 35 celsius or so. For my IBAD application and DP the DC702 and DC704 oil is better than the Santovac 5.DC705 was also not suggested? for this pump. Thanks a lot! Best Rergards! Attila ---In VacuumX@..., <chutko@...> wrote: Hi Attila, How are you? Hope everything is OK at your end. I didn't work with DP last 20 years, however I remember that overcooled water is also not good for DP because it leads to lower pumping speed and higher ultimate pressure. In case of too cool water you need to increase the heater power. Manufacturers usually recommend optimal inlet and outlet water temperature values. For instance, Leybold recommends inlet water temperature no more than 25C and outlet water temperature 30C, but they do not say anything about minimal values (but those values are different for different pumps and brands). As far as I remember, we always installed the control water valve and controlled water flow to get an optimal temperature by lowest ultimate vacuum and fast pumping speed. Do not forget, the cooling water must flow from the top input flange or baffle to the bottom output? flange. Best regards, Vladimir On 11/22/2013 1:39 PM, schneyolo@... wrote: Hello, |