The BPHE is in principle constructed as a package of corrugated channel plates between front and rear cover-plate packages. The cover-plate packages consist of sealing plates, blind rings and cover plates. Connections are mounted on the cover plates and can be customized to meet specific market and application requirements. During the vacuum-brazing process, a brazed joint is formed at every contact point between the base and the filler material. This design creates a heat exchanger that consists of two separate channels or circuits.
Sealing plates are used to seal off the space between the cover plate and the first and last channel plates. The number of cover plates varies, for example with the type and size of BPHE and its pressure rating. Some BPHEs have a blind ring to seal off the space between the channel plate and the cover plate. In others the blind rings are integrated in the cover plate and first/last channel plates.
Watch this short video showing the production steps in how BPHE's are made, from pressing plates, stacking and brazing to final testing and labeling.
BPHE plates and channel types
Certain BPHEs are available with different types of channel plates where the herringbone pattern varies. The benefit of different herringbone patterns is that the hydraulic and thermal characteristics of the BPHE can be modified. For example, two BPHEs can have the same pressure drop on both sides despite different flow rates.
The fluids can pass through the heat exchanger in different ways. For parallel flow BPHEs, there are two different flow configurations: co-current or counter-current (click images on the right).
- Co-current flow
- Counter-current flow
There are several different versions of the channel plate packages. Examples include:
- Dual-circuit BPHE
- Two-pass BPHE, which corresponds to two units connected in series.
- Dual-over-two-pass BPHE
There are different BPHE product categories depending on material combinations and design pressures. The standard plate materials are AISI 316 stainless steel, S, vacuum-brazed with a pure copper filler, C, or a nickel-based filler, N. For demanding applications, the plates can be made of SMO 254, a stainless steel with a higher content of molybdenum.