Plate heat exchangers exist in many industrial applications and primarily use metal plates to transfer heat between two fluids.
Their use is growing rapidly because they outperform traditional heat exchangers (usually a coiled tube containing one fluid that passes through a chamber containing another fluid) because the fluid being cooled is Greater surface area contact, which optimizes heat transfer and greatly increases the rate of temperature change.
Instead of coils passing through the chambers, in a plate heat exchanger, there are two alternating chambers, usually thin in depth, separated by corrugated metal plates at their largest surfaces.The chamber is thin, as this ensures that most of the liquid volume is in contact with the plate, aiding heat exchange.
Such heat exchange plates have traditionally been fabricated using stamping or conventional machining such as deep drawing, but recently photochemical etching (PCE) has proven to be the most efficient and cost-effective fabrication technique available for this rigorous application.Electrochemical Machining (ECM) is another alternative technology that can manufacture very precise parts in batches, but this process requires a very high level of upfront investment, is limited to conductive materials, consumes a lot of energy, the design and manufacture of tools is difficult, and the workpiece The corrosion of machine tools and fixtures has always been a headache.
Often, both sides of a plate heat exchanger contain extremely complex features that are sometimes beyond the capabilities of stamping and machining, but are easily achieved using PCE.Additionally, PCE can generate features on both sides of the plate simultaneously, saving significant time, and the process can be applied to a range of different metals, including stainless steel, Inconel 617, aluminum, and titanium.
Due to some inherent characteristics of the process, PCE offers an attractive alternative for stamping and machining in sheet metal applications.Using photoresist and etchant to precisely chemically process selected areas, the process features preserved material properties, burr- and stress-free parts with clean contours and no heat-affected zones.Additionally, the fluid etching medium creates an optimal structure for the fluid cooling medium used in the plate.These structures have no corners and edges susceptible to corrosion.
Combined with the fact that PCE uses easily repeatable and low-cost digital or glass tools, it provides a cost-effective, high-accuracy and fast manufacturing alternative to traditional machining techniques and stamping.This means significant cost savings when producing prototype tools, and unlike stamping and machining techniques, there is no tool wear and cost associated with re-cutting steel.
Machining and stamping can produce less-than-perfect results on metal at the cut line, often deforming the material being machined and leaving burrs, heat-affected zones, and recast layers.Additionally, they strive to meet the detail resolution required for smaller, more complex, and more precise metal parts such as heat exchange plates.
Another factor to consider in process selection is the thickness of the material to be machined.Traditional processes often encounter difficulties when applied to thin metal processing, stamping and stamping are in many cases unsuitable, while laser and water cutting lead to disproportionate and unacceptable levels of thermal deformation and material fragmentation, respectively.While PCE can be used in a variety of metal thicknesses, a key attribute is that it can work on thinner metal sheets, such as those used in plate heat exchangers, without compromising flatness, which is critical to the integrity of the assembly. important.
A key area where plates are used is in fuel cell applications made of stainless steel, aluminum, nickel, titanium, copper and a range of specialty alloys.
Metal plates in fuel cells have been found to have many advantages over other materials.At the same time, they are very strong, offer excellent conductivity for better cooling, can be fabricated extremely thin using etching, resulting in shorter stacks, and have no directional surface finish within the channel.Plates can be formed and channels created at the same time, and as mentioned above, no thermal stress is created in the metal, ensuring absolute flatness.
The PCE process ensures repeatable tolerances on all key board dimensions, including airway depth and manifold geometry, and can manufacture parts to tight pressure drop specifications.
Other industries that use chemically etched sheets include linear motors, aerospace, petrochemical and chemical industries.After fabrication, the plates are stacked and diffusion bonded or brazed together to make the core of the heat exchanger.Finished heat exchangers can be up to six times smaller than traditional “shell and tube” heat exchangers, providing excellent space and weight advantages.
Heat exchangers produced using PCE are also very robust and efficient, able to withstand a pressure of 600 bar while adapting to a temperature range from cryogenics to 900 degrees Celsius.It is possible to combine more than two process streams into one unit and meet the requirements on piping and valves are greatly reduced.Reaction and mixing can also be integrated into the plate heat exchanger design, cost-effectively adding functionality in a single unit.
Today’s requirements for efficient and space-saving heat dissipation present enormous challenges to many development engineers.The miniaturization of many components in electrical and microsystem technology creates so-called thermal hot spots, which require optimal heat dissipation to ensure a long service life.
Using 2D and 3D PCE, microchannels with defined widths and depths can be fabricated in heat exchangers for the selection of heat dissipation media in the smallest area.There is almost no limit to the possible channel designs.
Furthermore, since the etching process inspires design innovation and geometric freedom, turbulent flow as opposed to laminar flow can be promoted through the use of wavy channel edges and depths.Turbulent flow in the cooling medium means that the coolant in contact with the heat source is constantly changing, which makes heat exchange more efficient.Such corrugations and irregularities in microchannels in heat exchangers are easily produced by PCE, but are not possible or cost-prohibitive to produce using alternative manufacturing processes.
PCE specialist micrometal GmbH uses competitively priced optoelectronic tools to produce high-quality workpieces with a high degree of repeatable accuracy.
Individual microchannel plates can be attached (eg, by diffusion welding) to various 3D geometries.micrometal uses an experienced partner network that gives customers the option to purchase individual microchannel plates or integral microchannel heat exchanger blocks.
A substance having metallic properties and consisting of two or more chemical elements, at least one of which is a metal.
Reduce fluid temperature increases at the tool/workpiece interface during machining.Usually in liquid form, such as soluble or chemical mixtures (semi-synthetic, synthetic), but can also be pressurized air or other gases.Due to its ability to absorb large amounts of heat, water is widely used as a coolant and carrier for various cutting compounds, and the ratio of water to compound varies with the machining task.See cutting fluid; semi-synthetic cutting fluid; soluble oil cutting fluid; synthetic cutting fluid.
1. Diffusion of a component in a gas, liquid, or solid that tends to make the components uniform.2. An atom or molecule spontaneously moves to a new location within the material.
An operation in which electric current flows between a workpiece and a conductive tool through an electrolyte.Initiates a chemical reaction that dissolves metal from the workpiece at a controlled rate.Unlike conventional cutting methods, workpiece hardness is not a factor, making ECM suitable for difficult-to-machine materials.In the form of electrochemical grinding, electrochemical honing and electrochemical turning.
Functionally the same as a rotary motor in a machine tool, a linear motor can be thought of as a standard permanent magnet rotary motor, cut axially in the center, then stripped and laid flat.The main advantage of using linear motors to drive axis motion is that it eliminates the inefficiencies and mechanical differences caused by the ball screw assembly systems used in most CNC machine tools.
Wider spaced components in the surface texture.Include all irregularities spaced wider than the instrument cutoff setting.See Flow; Lying; Roughness.
Dr. Michael J. Hicks is Director of the Center for Business and Economic Research and the George and Francis Ball Distinguished Professor of Economics at Ball State University’s Miller School of Business.Hicks received his Ph.D. and M.A. in Economics from the University of Tennessee and a BA in Economics from the Virginia Military Institute.He has authored two books and more than 60 scholarly publications focusing on state and local public policy, including tax and spending policy and the impact of Walmart on local economies.