勝川熱工 List of Products and Services

Katsukawa Thermal Engineering is one of the few manufacturers in Japan that has consistently engaged in the design and manufacturing of heat exchangers suitable for dehumidification devices and factory production cooling lines since 1934. Our plate fin coolers are used in various industrial fields for cooling, dehumidification, heat recovery, and improving working environments. 【Katsukawa Thermal Engineering's Plate Fin Cooler】 - Utilizes stainless steel heat exchangers that require low replacement frequency and can be used without difficulty. - Water or refrigerant is passed through the heat transfer tubes, while air or gas is circulated on the casing side for cooling. - Capable of designing systems suitable for a wide range of cooling and dehumidification applications, including pollution control devices for media containing pharmaceuticals, dairy products, beverages, food, polymers, chemical products, ceramics, and organic substances. To avoid troubles with heat exchangers used in production processes and ensure stable production, it is important to select a manufacturer with experience and responsiveness. *We are currently offering a free copy of "Basic Knowledge and Selection Guide for Heat Exchangers." Please view it via the "PDF Download" link below. Feel free to contact us for estimates or inquiries.

• Cooling system

Our company provides comprehensive support from the design and manufacturing of industrial heat exchangers to usage advice and maintenance after delivery. We can respond quickly in the event of issues such as steam leaks, liquid leaks, or tube blockages. In Japan, we dispatch engineers within the same day to the next day, and for overseas (Asia, Europe, America, etc.), we can send engineers in as little as three days. We investigate the nature and cause of the trouble and perform parts replacement or disassembly and cleaning as needed. 【Our Strengths】 ■ Extensive experience and achievements cultivated since our founding in 1934 ■ Ability to identify the causes of troubles that often arise from multiple factors ■ Dispatching engineers to the site even when the nature of the trouble is unclear ■ Investigating the cause of troubles to prevent recurrence, even when there are no issues with the heat exchanger ★ We are currently offering materials on troubleshooting steam heater coils. Please check the download button for more details. Feel free to contact us with any inquiries.

• Heat exchanger

Katsukawa Thermal Engineering is one of the few manufacturers in Japan that has consistently engaged in the design and manufacturing of heat exchangers suitable for drying machinery and factory production drying lines since 1934. Katsukawa Thermal Engineering's plate fin heaters are used in various industrial fields for drying, cooling, dehumidifying, and heat recovery. 【Katsukawa Thermal Engineering's Plate Fin Heater】 - The fin area is larger than that of an elofin heater, resulting in fewer tubes, making it compact, lightweight, and cost-effective to manufacture. - Steam flows inside the heat transfer tubes, while air or gas passes through the casing outside the tubes to heat the air or gas. - It can be designed to adapt to a wide range of hot air drying systems, including pollution control devices for media containing pharmaceuticals, dairy products, beverages, food, polymers, chemical products, ceramics, and organic materials. To avoid troubles with heat exchangers used in production processes and to ensure stable production, it is important to select a manufacturer with experience and responsiveness. *We are currently offering a free "Basic Knowledge and Selection Guide for Heat Exchangers." Please view it via the "PDF Download" link below. Feel free to contact us for quotes or inquiries.

• Heat exchanger

We custom-manufacture "Elophin Heaters" for heating air (gas) incorporated into drying equipment, facilities, and air conditioning equipment. The fin tube, which wraps a metal plate around the heat transfer tube, exhibits high heat dissipation. It is widely used as a heat source for steam, hot water, and thermal oil, and is commonly employed in steam coils for air conditioning systems, as well as in steam heaters for drying industrial products and warming cabinets. It is easy to clean and repair, making it suitable for process air conditioning in various manufacturing lines. We can provide proposals based on your specific usage needs. 【Features】 ■ Various fin materials available: SS, SUS, copper, aluminum ■ Zinc plating, tin plating, and brazing processing available for fin tubes ■ Custom manufacturing of pipes and fins from special metals is also supported ★ We are currently offering a "Basic Knowledge and Selection Guide for Heat Exchangers," which includes examples of applications in manufacturing lines. You can view it immediately by clicking the download button. Please feel free to contact us with any inquiries.

• Heat exchanger

We propose heat exchangers suitable for factory equipment and machinery for drying, cooling, and dehumidifying.

• others

In the heating and drying processes of industrial products, heaters utilizing indirect heating with steam or thermal oil are employed. Our "LS Fin Tube Heat Exchanger" has been developed by considering both the advantages and disadvantages of the Erofin type and the plate fin type. <Features of Erofin Type> - Superior adhesion between fins and heat transfer tubes compared to plate fin type, but inferior in heat transfer area. - Arrangement and spacing between fin tubes are flexible. - A higher number of tubes and longer effective length increase costs. <Features of Plate Fin Type> - Inferior adhesion between fins and heat transfer tubes compared to Erofin type, but allows for a larger heat transfer area. - Lower flexibility in arrangement and spacing between fin tubes. - Difficult to clean and maintain. <Features of LS Fin Tube Type> - By wrapping the fins in an L-shape, the contact area with the heat transfer tubes is increased, improving heat transfer efficiency. - High heat transfer coefficient allows for fewer tubes than Erofin type, enabling cost reduction. - Arrangement and spacing between fin tubes can be freely determined, similar to Erofin type. - Longer effective length and a higher number of tubes make plate fin type more advantageous. *In addition to the product catalog, we are also providing basic knowledge materials on heat exchangers.

• Heat exchanger

At Katsukawa Thermal Engineering, we design and manufacture "heat exchangers" necessary for heating, cooling, and dehumidifying in the production processes of industrial products. To create structures suitable for various industries, taking into account applications and usage environments, a wealth of experience is required. Our company offers our long-standing experience and achievements as assets to meet our customers' needs. We have two factory facilities and are fully prepared to handle urgent repair requests. We can achieve low-cost and space-saving solutions with heat media, shapes, and materials suitable for the application. Please feel free to contact us for inquiries regarding drying, cooling, dehumidifying, and waste heat recovery. [Application Examples] Coating and drying equipment related to the coating and laminating of chemical fibers, films, flat displays, lithium-ion batteries, etc. *In addition to our company brochure, we are currently offering materials that explain the basics of heat exchangers. You can view them immediately via "PDF Download."

• Heat exchanger

Our company designs and manufactures "multi-tube (shell & tube) heat exchangers" that can be utilized for heat exchange between liquids. In addition to standard products listed in the specification sheet, we also accommodate custom-made products, and it is possible to adjust the structure for easy integration into existing equipment. The fluids inside the tubes can include steam, thermal oil, hot water, cold water, and cooling water. Due to its simple system, we can offer it at a reduced total cost. 【Features】 ■ Can be manufactured as a Class II pressure vessel or small pressure vessel ■ Some Class I pressure vessels are also available ■ Sanitary specifications are available for medical and food applications ■ We provide proposals utilizing our specialized knowledge and experience as a heat exchanger manufacturer, tailored to specification conditions and applications ★ You can view materials that introduce basic knowledge useful for selecting heat exchangers from the "PDF Download" section. Please feel free to contact us.

• others

Katsukawa Thermal Engineering has 86 years of history and experience in the design and manufacturing of heat exchangers that support the cooling and heating of production lines. We propose suitable combinations, shapes, and materials of heat transfer media for various applications such as metals, machinery, textiles, chemicals, ceramics, food, and paper/pulp. We can accommodate various types of heat exchangers, including finned tube, plate, and shell & tube types. We respond to our customers' needs by creating low-cost, space-saving, and high-quality products. Please feel free to contact us. *In addition to our company brochure, we are currently offering materials that explain the basic knowledge of heat exchangers. You can view them via "PDF Download."

• Heat exchanger

The "LS Fin Tube" features fins wrapped around the outer circumference of a pipe in an L-shape, increasing the contact surface area with the pipe to enhance thermal conductivity. When adopted in hot air circulation dryers, it demonstrates equivalent drying performance even when the heat transfer area is significantly reduced to about half that of our conventional product, the Erofin Heater. (Note 1) This contributes to total cost reduction in terms of heater price, weight, and fan static pressure reduction. A wide range of outer pipe diameters is available, making it easy to replace existing Erofin tubes. ■ Achieves high heat exchange efficiency while minimizing heat transfer area ■ Enables space-saving and energy-efficient equipment ■ Wide lineup of outer pipe diameters from Φ16mm to Φ76.3mm ■ Suitable for large dryers and air conditioning units, just like Erofin tubes ★ For more details, please refer to the catalog available for download as a PDF. We are also providing materials that introduce the basics of heat exchangers, their types, and their roles in manufacturing lines.

• others

Since our establishment in 1934, we have been designing and manufacturing industrial heat exchangers. Here are two of our key products. "Elfin Tube" - Radiant heat, geothermal, and hot spring water utilizing finned radiators - Active in production equipment such as semiconductor-related devices and plating product dryers - Improved conductivity through winding processing that ensures fins are fully adhered to the pipe - Materials can be freely combined from SS, SUS, and CU "Unit Heater" - Effective utilization of thermal energy including steam and hot water - Suitable for heating factories with low ceilings and drying rooms for plastic molding - In spaces with high ceilings, combining with V-type unit heaters enhances heating effectiveness - Custom manufacturing available with various special motors and stainless materials *For more details, please refer to the materials. Feel free to contact us with any inquiries.

• Heating and cooling equipment and facilities

Our "Plate Fin Cooler" has a proven track record as a heat exchanger for cooling and dehumidifying environments, with numerous installations in air conditioning systems, exhaust gas treatment, and waste heat recovery applications. We offer a lineup that includes in-equipment installation types and airtight duct types, allowing for selection based on purpose and application, including general air conditioning, industrial air conditioning systems, and environmental protection devices. With extensive experience and knowledge in designing air conditioning and dehumidifying equipment that controls temperature and humidity individually, we provide strong support for equipment design. 【Features】 ■ Fin pitch is variable from 2.8mm ■ Compatible with zinc and tin plating ■ Excellent corrosion resistance with SUS tubes + SUS fins ■ Custom manufacturing with special metals is also available *For more details, please refer to the PDF document. Feel free to contact us with any inquiries. (Please note that the fin pitch is listed as 3.0mm in the catalog. Thank you for your understanding.)

• others

The Erofin tube uses our unique machine to automatically perform a complete and tight winding process around the outer circumference of the pipe, maintaining an integrated structure and achieving excellent thermal conductivity. The outer diameter, length, width, and pitch of the fins can be customized in various ways according to your requirements. Additionally, the pipe and fins can be combined with stainless steel, iron, and copper for the winding process. It is widely used in heating and drying equipment for natural convection and forced ventilation. 【Features】 ◎ Superior fin adhesion rate, fin pitch accuracy, and impact resistance compared to conventional products ◎ In addition to standard specifications, we can also produce pipes with diameters, fin heights, and fin pitches close to specifications ◎ Effective lengths of up to 6.0m can be produced, starting from just one piece ★ We are currently offering "Product introduction materials" and "Materials containing basic knowledge about heat exchangers"! Please check the PDF download for more details. Feel free to contact us with any inquiries.

• Audio equipment

Plate fin heaters are used as heaters to heat air with steam/hot water/thermal medium oil. Most steam coils and hot water heaters used in air conditioning systems are either elofin or plate fin heaters. They are suitable for process air conditioning. Plate fin heaters have a larger fin area than elofin heaters, which allows for fewer tubes, making them compact, lightweight, and cost-effective to manufacture. Currently, they are in higher demand than elofin heaters, except in cases where elofin is specifically chosen for certain applications. Like elofin heaters, plate fin heaters are primarily designed for heating air and other gases and are incorporated into air conditioning units, drying equipment, and other devices. The structure consists of a coil element with various thin metal plates pressed (inserted) onto tubes (heat transfer tubes), which are then welded to a tube bundle (header) and housed within a steel duct-type casing. Katsukawa Thermal Engineering's heat exchanger designs are based on years of accumulated knowledge tailored to various industrial applications. We provide prompt and suitable designs and proposals based on customer specifications. *For more details, please download the catalog below.

• Heat exchanger

At Katsukawa Thermal Engineering, we supply steam piping along with heat exchangers. We offer vertical tube-type heaters (with horizontal airflow) and horizontal tube-type heaters (with vertical airflow). Our sales engineering team conducts piping diagnostics, so we provide on-site assessments for users who experience issues such as damage after replacing heat exchangers multiple times. [Features] [Steam Heater and Steam Piping Construction] - We handle the design and construction of steam piping for steam heaters. - We have extensive experience with steam equipment that complies with domestic regulations and international standards. For more details, please contact us or download the catalog.

• Heating and cooling equipment and facilities

The welding fin tube fins are continuously welded to the tube by spirally wrapping the fins around it using high-frequency resistance welding. The fin and pipe welding of the Erofin tube is only at both ends. 【Features】 [Welding Fin Tube Flange Type] ○ Excellent durability and thermal conductivity, can be used semi-permanently ○ No reduction in capacity due to damage For more details, please contact us or download the catalog.

• Imported houses and log houses

LS fin tubes are processed with L-shaped fins automatically and completely adhered to the outer circumference of the pipe using our unique special machine, allowing for heat transfer efficiency comparable to that of integral structures like rolled fins. The LS fins developed by Katsukawa Thermal Engineering Co., Ltd. are wrapped in a spiral using a special crimping method, resulting in a larger contact area and superior adhesion compared to conventional elofin tubes, achieving high thermal conductivity. 【Features】 ○ Exhibits higher performance than elofin tube types under certain conditions ○ When used in circulation-type drying ovens (dryers), it can fit into approximately half the heat transfer area compared to elofin types at maximum For more details, please contact us or download the catalog.

• Imported houses and log houses

Plate fin tubes are fin tubes that can combine pipes and fins made of various materials. The key to plate fins is pitch accuracy, and thanks to our self-developed high-performance servo motors, we can achieve high precision with an allowable error of less than 3mm over an effective length of 3000mm, proudly reproducing the design capabilities faithfully. 【Features】 ○ High-precision plate fin elements ○ Fin pitch error is less than 3mm over an effective length of 3000mm ○ Independently developed plate fin manufacturing machine ○ Fin pitch controlled in 0.1mm increments using NC control For more details, please contact us or download the catalog.

• Imported houses and log houses

Our company manufactures "unit heaters" for factories and facilities. The "V type" is designed to efficiently raise the temperature in large spaces such as factories, gymnasiums, and markets by blowing hot air from near the ceiling with strong pressure towards the floor, allowing the warm air layer to spread across the floor. It continuously creates an upward airflow, maintaining a uniform temperature throughout the room. The "KKL type" is suitable for heating low-ceiling factories, drying rooms, and spot heating applications. [Usage Scenarios] [V type] Ideal for heating high-ceiling factories, water drainage drying rooms, and insulation cabinets (for plastics, styrofoam, ceramics). [KKL type] Ideal for heating low-ceiling factories, drying rooms (for wood, plastic molding, livestock barns), and spot heating in work areas. ★ In addition to product materials, we are also providing documents summarizing basic knowledge about types and applications of heat exchangers. You can view them via "PDF Download."

• Heating and cooling equipment and facilities

The hot air generation device is a unit that combines a heater and a fan. The size of the heater and the type of fan are selected based on the processing air volume, temperature conditions, required heat quantity, and intended use. Heaters for manufacturing lines become component elements, while the hot air generation device serves as a component of the drying device. The drying device is optimally shaped for various drying applications, with the hot air generation device installed on the upper part or outside of the equipment. 【Features】 ○ Environmentally friendly heating device utilizing natural convection with steam ○ Suitable for heating in explosion-proof areas without a fan ○ Can be designed for hot water ○ Internal elements can be selected from plate fins or elofins For more details, please contact us or download the catalog.

• Heating and cooling equipment and facilities

The LS fin heater is a heater made using the LS fin tube, which has been developed as a next-generation fin tube to replace the existing fin heaters used for dryers. It resolves the issues associated with heaters that use aluminum fin tubes, which have durability problems. This allows for a reduction in total costs, including heater price, weight, and fan static pressure. 【Features】 ○ When adopted in a circulation drying furnace (dryer), it can fit within about half the heat transfer area compared to the fin type. 　→ If two existing fin heaters were needed, one unit can meet the required capacity. ○ Total costs can be reduced, including heater price, weight, and fan static pressure. ○ It can be installed as a replacement when updating from existing fin heaters. For more details, please contact us or download the catalog.

• others

The plate fin cooler is a coil element made by pressing various thin metal plates onto tubes (heat transfer pipes), similar to a plate fin heater. To create water channels or water chambers, U-tube (U-bend) tube bundles (headers) are attached to the tubes through suitable welding processes, and these are housed within a duct-type casing made of steel plates. The plate fin cooler is used to cool water, refrigerants, and various gases outside the pipes. 【Features】 - Optimal as a heat exchanger for various equipment - Usable for cooling and dehumidifying in all environments - Strong support for users' equipment design with rich experience and knowledge For more details, please contact us or download the catalog.

• others
• Heat exchanger

Plate fin heaters are used as heaters to heat air with steam/hot water/thermal oil. Most steam coils and hot water heaters used in air conditioning systems are either elofin or plate fin heaters. They are ideal for process air conditioning. 【Features】 ○ Since the fin area is larger than that of elofin heaters, the number of tubes can be reduced, making them compact, lightweight, and cost-effective to manufacture. ○ There is a higher demand compared to elofin heaters. ○ These heaters are designed for heating air and other gaseous substances and are incorporated into air conditioning units, drying equipment, and dryers. For more details, please contact us or download the catalog.

• Heat exchanger

This heater is primarily designed for heating air and other gases and is incorporated into air conditioning units, drying equipment, and dryers. Its structure consists of multiple fin tubes welded to a header and housed within a duct-type casing made of steel plates. Most steam coils and hot water heaters used in air conditioning systems are either finned or plate fin heaters. 【Features】 - Fin pitch can be customized starting from 3.0mm. - Zinc or tin plating can be applied to fin tubes upon request. - We can accommodate requests for pipes and fins made of special metals. For more details, please contact us or download the catalog.

• Heat exchanger

At Katsukawa Thermal Engineering Co., Ltd., we offer a wide range of heat exchangers tailored to various applications, including "high static pressure hot air blowers heat exchangers," "N2 gas heater heat exchangers," and "solvent recovery units." 【Units】 ○ Solvent Recovery Unit ○ Air Conditioning Unit For more details, please contact us or download the catalog.

• Transportation System
• Other elevators and transport systems
• Heat exchanger

The multi-tube heat exchanger is primarily a heat exchanger using liquid-to-liquid media. It has a structure where numerous narrow heat transfer passages are arranged within a cylindrical body, allowing for heat exchange between fluids with different temperatures inside and outside the heat transfer tubes. Heat exchange between liquids using a multi-tube heat exchanger is systemically simple and results in the lowest total cost. In design and manufacturing, adjustments will be made to ensure a structure that can be easily integrated into existing equipment. 【Features】 ○ Achieves high-efficiency heat exchange ○ Compact design minimizes installation space ○ Can be installed in an inline configuration (both vertical and horizontal orientations are acceptable!) ○ Utilizes SUS304, 316L, and titanium for high corrosion resistance For more details, please contact us or download the catalog.

• Heat exchanger

At Katsukawa Thermal Engineering Co., Ltd., we offer "renovation of air conditioning units (AHU)" by replacing only the coils inside the air handling units (AHU). Unless the entire air conditioning unit is significantly aged, the AHU itself can continue to be used by simply replacing the coils, which allows for substantial cost savings on repairs. We also accept orders for the new manufacturing of air conditioning units (AHU). 【Features】 ■ Cost reduction through coil replacement of high-cost equipment such as air handling units and air conditioning units ■ Nationwide service available ★ For more details, please check the catalog available for download as a PDF. We are also providing materials that introduce basic knowledge about heat exchangers, their types, and their roles in the manufacturing line.

• Heat exchanger

Here are examples of using heat exchangers for renewable energy. The Oguni Town Forest Association, which has been operating since 2009 to dry local timber using geothermal energy and supply high-quality, flavorful wood products, has introduced our heat dissipation pipes (Elofin tubes). By not using fossil fuels like traditional steam drying kilns, they can perform drying that is friendly to both the environment and the wood, without emitting carbon dioxide. [Overview] - Demonstration of the potential for utilizing geothermal energy - Methods of using Elofin tubes For more details, please contact us or download the catalog.

• Heat exchanger

At Katsukawa Thermal Engineering Co., Ltd., we provide heat exchangers aimed at the reuse of heat. The "plate heat exchanger" is a direct counterflow type heat exchanger designed for heat recovery, utilizing a gas-to-gas system that does not contain dust. The plate heat exchanger consists of two metal plates that are pressed into a wavy shape and welded together to form a pair, which can be combined in multiple pairs to increase the heat transfer area. The gas on the heating side and the gas on the cooling side are structured to prevent mixing through welding, and the wavy shape of the heat transfer plates takes thermal expansion differences into account. Additionally, similar to the plate heat exchanger, we also handle "feedwater preheaters (economizers)" used to preheat the feedwater in order to increase boiler efficiency. 【Features】 ○ Heat exchangers to enhance boiler thermal efficiency ○ Reuse of heat from exhaust gases emitted from the boiler ○ Supply preheated fresh air to the boiler to improve combustion efficiency ○ Air preheating is incorporated into the combustion system to enhance combustion efficiency and is widely used for energy savings, such as reducing fuel costs. For more details, please contact us or download the catalog.

• Heat exchanger

Katsukawa Thermal Engineering is a specialized manufacturer of finned tube heat exchangers for process air conditioning, primarily focusing on the Elofin and plate fin types necessary for industrial process air conditioning. Since our founding in 1934, we have continued to prioritize "technology," "speed," and "trouble-solving ability," while also investing in the development of engineers. We have delivered numerous heat exchangers to a wide range of industries, including automotive, pharmaceuticals, semiconductors, and food manufacturers. We take pride in our design and technical capabilities, which set us apart from other companies. We provide high-quality products based on reliable technology at short lead times and low costs. 【Wide Range of Heat Exchangers Supported】 - Heaters & coolers used in dryers, coolers, dehumidifiers, etc., for heating and cooling industrial products - Unit heaters for heating - Hot and cold water coils in air conditioning units - Radiant pipes for agriculture and horticulture, and radiant pipes for snow melting in cold regions, etc. For more details, please contact us or download our catalog.

• Heat exchanger

Katsukawa Thermal Engineering Co., Ltd. is a specialized manufacturer of finned tube heat exchangers for process air conditioning, primarily using the Elofin and plate fin types, necessary for industrial process air conditioning. Since its establishment in 1934, we have continued to focus on "technology," "speed," and "trouble-solving ability," investing in the development of engineers and delivering numerous heat exchangers to a wide range of industries (automotive, pharmaceuticals, semiconductors, food manufacturers, etc.). We take pride in our design and technical capabilities, which set us apart from other companies. We provide high-quality products based on reliable technology at short lead times and low costs. There are various types of heat exchangers depending on their applications. Katsukawa Thermal Engineering specializes in heat exchangers for "liquid x gas" and accommodates a wide range of products. While many heat exchangers are sold as one-time products, Katsukawa Thermal Engineering offers comprehensive support, including design and manufacturing, advice on installation environments and usage, and maintenance after delivery. You can rest assured in the event of any failures or troubles. Our engineers will respond immediately. Additionally, you can trust Katsukawa Thermal Engineering with any issues or troubles related to products from other companies. For more details, please contact us or download our catalog.

• Heat exchanger

"LS Fin" is a product where fin material for heat dissipation is spirally wrapped around a heat transfer tube in an angled shape using a special crimping method. It has a larger contact area compared to conventional fin tubes, allowing for a high thermal conductivity that enables a compact design. Low static pressure blowers can also be used, making it possible to create a cost-effective overall system. As a company specializing in custom orders, we can manufacture products according to the user's specifications for dimensions and capacity in a short lead time and at a low price. [Features] ■ Larger contact area than conventional fin tubes ■ Excellent adhesion ■ High thermal conductivity ■ Compact design possible ■ Supports short lead times and small lots *For more details, please refer to the PDF materials or feel free to contact us.

• Heat exchanger

Heat exchangers are used in various applications such as heating, cooling, and drying of industrial products, but selecting the right heat exchanger that fits the equipment and machinery requires knowledge and experience. At Katsukawa Thermal Engineering, we have been providing heat exchangers that embody our customers' voices based on the experience and know-how accumulated over many years. We own a large number of specialized machines for various types of finned tubes as part of our in-house facilities. We respond to requests by leveraging our high production capacity and the advantages of our industrial region. For inquiries regarding heat exchangers for manufacturing lines in sectors such as semiconductors, automotive, food, machinery, chemicals, pharmaceuticals, mining and manufacturing, paper, and pulp, please feel free to contact us. 【Products Offered】 ■ LS finned tube heat exchangers ■ Ero finned tube heat exchangers ■ Plate finned tube heat exchangers *We are currently offering materials summarizing basic knowledge and applications of heat exchangers! You can view them via PDF download.

• Heat exchanger