BDU-series beam dumps are designed to absorb incident CO2 laser radiation in a hollow conical
section of the dump block. Water cooling is provided to remove the absorbed heat. Two standard
models are made, and these are designed to fit to ‘25’ and ‘38’ series beam delivery equipment.
Available models : BDU25, BDU38
Dimensions : See Figure 69.01 and Table 69.02
Construction : Aluminium HE30
Finish : Black anodised
Max power : ~ 3kW for BDU25, ~ 5kW for BDU38
Fittings : See Table 69.02 for thread fittings on free-rotating connector ring.
Water cooling must be supplied for dumped power levels in excess of about a few ten’s of watts. The
rate of water supply required is related to the allowed temperature increase which may be specified
by the user. Suppose this is ΔT degrees C, and the power dumped is P watts.
Rate of water supply needed = P/4.2ΔT cm3 per second.
Translated into litres per minute flow, and with the power in kilowatts:
Rate of flow required ~ 14/ΔT litres per minute per kW. For everyday purposes, dT might be, say,
10°C. So ~ 1.4 litres per minute per kW would be a reasonable water supply rate.
Model BDU25 is a direct fit to the following equipment
OPG piping : Section 61.1
ESU20 shutter unit : Section 76.0
BSC25/beam sampler units : Section 68.0
Model BDU38 is a direct fit to the following equipment
LPG piping : Section 61.1
BSC38/beam sampler units : Section 68.0