Brazed Plate Heat Exchanger L95A

Product Introduction

The brazed plate heat exchanger is formed by permanently connecting multiple layers of stainless steel plates through the brazing process. Its core structure is composed of corrugated plates, brazing materials (usually copper or nickel), and an external frame. The corrugated design between the plates forms complex flow channels, enabling the cold and hot media to flow in opposite or cross directions within adjacent channels, thus achieving rapid heat exchange.

Brazed plate heat exchangers and ordinary plate heat exchangers (usually referring to detachable plate heat exchangers) have significant differences in structure, process and application. The main differences are as follows:

Basic structure

The brazed plate heat exchanger is integrally formed. The stainless steel plates are permanently welded into a whole through high-temperature brazing (copper or nickel-based brazing filler metal), without sealing gaskets or frame structures. Smaller in volume, lighter in weight, with a denser corrugated design on the plates and higher pressure-bearing capacity (up to over 30 bar)

The common plate heat exchanger (detachable type) is modularly set up, assembled from independent plates, rubber sealing gaskets and metal frames, and tightened by bolts. The plates and gaskets can be replaced separately, but they are relatively large in volume and have a lower pressure resistance (usually ≤16 bar).

Plate: Made by stamping thin plates of corrosion-resistant metals such as stainless steel and titanium into a corrugated shape, the corrugated design enhances turbulence and mechanical strength.

Brazing process: The plates are fused at high temperature in a vacuum brazing furnace with copper or nickel-based brazing filler metal to form a sealed flow channel, without the need for rubber gaskets (different from detachable plate heat exchangers).

Flow channel layout: Cold and hot fluids alternate through adjacent flow channels, usually designed as counter-flow or cross-flow to enhance heat exchange efficiency.

Operating principle

Fluid flow and distribution

Multi-channel design: Cold and hot fluids flow parallel (counter-current, co-current or cross-flow) between alternating plates, forming complex paths through corrugation guidance, prolonging residence time and enhancing turbulence.

Counter-flow advantage: The common counter-flow arrangement (with the fluid direction opposite) can maximize the logarithmic mean temperature difference (LMTD) and improve heat transfer efficiency.

Heat transfer mechanism

Conduction: Heat is conducted through the metal plates from the high-temperature fluid to the low-temperature fluid. The brazing layer ensures that the thermal resistance between the plates is minimized.

Convection: The corrugated structure disruptors the laminar boundary layer, generating intense turbulence (Reynolds number Re > 2000), significantly enhancing the convective heat transfer coefficient (up to 3 to 5 times that of shell and tube heat exchangers).

Pressure drop and flow resistance

The shape of the corrugations and the spacing of the plates affect the pressure drop: Herringbone corrugations have strong turbulence but high pressure drop, making them suitable for low-resistance designs (such as inclined corrugations)
In high-traffic scenarios.

Application scenarios

Brazed plate heat exchangers are applied in high-pressure/high-purity medium environments such as refrigeration (air conditioning, heat pumps), petrochemicals, and shipping.

Detachable plate heat exchangers are applied in industries such as food and beverage, HVAC, and pharmaceuticals, where frequent cleaning or medium replacement is required.

Refrigeration: Used as an evaporator or condenser (such as in air conditioners and heat pumps).

Industry: Hydraulic oil cooling, process heating/cooling.

New energy: Thermal management of fuel cells, cooling of electric vehicle batteries.

Manufacturing process

The brazed plate heat exchanger is welded at high temperature in a vacuum brazing furnace to form an undetachable rigid structure with no leakage points (except for the inlet and outlet).

Detachable plate heat exchangers rely on gaskets for sealing. Gaskets need to be inspected or replaced regularly to prevent leakage.

Cost and Lifespan

The initial cost of brazed plate heat exchangers is relatively high, but they have a long service life (no gasket aging problem) and are suitable for long-term stable working conditions.

Detachable plate heat exchangers are used in scenarios where the medium is prone to scaling, requires frequent cleaning, or has variable working conditions.