Multi-pass heat exchangers: comparison of manufacturers 

Why the number of strokes determines the efficiency of your heat exchanger

Multi-pass heat exchangers: Comparing manufacturers is not just an academic exercise, but a critical part of equipment selection that will determine the energy efficiency of the entire plant for the next 15-20 years. In our practice, we have repeatedly encountered a situation where buyers chose a device solely based on the price per square meter of heat exchange surface, ignoring the flow pattern. The result is predictable: after six months of operation, the system did not produce the required power, and the hydraulic resistance was three times higher than designed. The choice between a two-, four- or six-pass circuit is dictated not by the availability of free money in the budget, but by a strict ratio of the costs of the heating and heated media, as well as the permissible pressure drop in the system.

The industrial heat transfer equipment market in 2026 is oversaturated with offers, with Chinese, Russian and European brands competing for the attention of engineers. However, beautiful catalogs often hide fundamental differences in engineering philosophy. European manufacturers rely on modularity and precision of plate stamping, Russian ones on maintainability and operation in extreme conditions, and Chinese factories offer aggressive prices given the rapidly changing quality of the metal. Understanding these nuances allows you to avoid production line downtime due to depressurization or corrosion.

In this article we will not give abstract advice. We will analyze specific technical parameters that influence the choice of the number of strokes, analyze real cases of unsuccessful installations and provide a comparative table of leading manufacturers in terms of compliance with GOST and ISO standards. If you are looking for equipment that will last longer than the warranty period, this information will save you budget for unscheduled repairs.

The technical essence of multiple skipping: when two moves are better than one

The number of strokes in a plate heat exchanger is a parameter that directly affects the flow rate of the medium inside the channels and, as a result, the heat transfer coefficient. When we talk about a “multi-pass” circuit, we mean that the fluid passes through the plate stack several times, changing direction due to a special arrangement of ports and baffles in the distribution chamber. This is necessary when the flow rate of one of the media is significantly less than the other, or when it is necessary to ensure high turbulence with small pumping volumes.

Let's look at a typical design mistake. The engineer selects a device for heating a small flow of viscous oil with a large amount of steam. If you choose a single-circuit (single-pass) circuit, the oil will move too slowly. Laminar flow will create a stagnation zone at the walls of the plates, which acts as a heat insulator. The heat transfer coefficient will drop catastrophically. Switching to a two- or four-pass scheme artificially increases the flow rate in the channels by 2 or 4 times, respectively. This destroys the boundary layer and intensifies heat transfer.

However, there is another side to the coin. An increase in the number of strokes inevitably leads to an increase in hydraulic resistance. Pumping equipment designed for single-pass mode may simply not be able to force the medium through a four-pass package. The pressure will increase exponentially. In one of our projects, the client insisted on installing a six-way circuit to save space, without agreeing with the characteristics of the pump. The result: the pump motor burned out after two weeks of operation, and the system’s performance dropped to zero. Therefore, the rule is simple: we increase the number of strokes only after verifying the pump pressure.

There is also a temperature limit. With repeated passes, zones of local overheating or hypothermia arise due to the uneven distribution of temperatures along the length of the apparatus. For standard heating and domestic hot water tasks, 1-2 strokes are usually sufficient. For technological processes in the food or chemical industry, where precise temperature schedules for pasteurization or cooling of the reaction mass are important, complex circuits with 4, 6 and even 8 passes are often required. High-level manufacturers are required to provide software calculations that clearly show the temperature distribution for each stroke.

It is important to understand the difference between true multi-pass devices and pseudo-multi-pass solutions, where an increase in the number of strokes is achieved by connecting several individual devices in series. A monoblock solution with internal partitions is more compact and cheaper to install, but more difficult to maintain. Disassembling such a device requires a strict tightening sequence of bolts, otherwise the geometry of the package will be disrupted and leaks will occur between strokes. This is the case when the qualifications of the installation team are more important than the brand of the hardware itself.

Comparative analysis of manufacturers: Europe, Russia and China

Selecting a multi-pass heat exchanger manufacturer today comes down to a balance between cost of ownership (TCO) and initial capital expenditure. The market is clearly segmented, and each region offers its own advantages and hidden risks. Below we provide a detailed analysis of the three main groups of suppliers, based on our experience in operating and servicing hundreds of pieces of equipment.

European brands (Alfa Laval, GEA, Sondex)

Market leaders such as the Swedish Alfa Laval or the German GEA have been setting the tone in the industry for half a century. Their main advantage is the highest precision of plate stamping and the quality of rubber seals. In multi-pass circuits, where the requirements for tightness between chambers are critically high, European seals made of EPDM or Viton last up to 7-10 years without loss of elasticity. The frame design of these manufacturers makes it easy to change the number of strokes by simply rearranging the partitions, often even without completely disassembling the package.

However, the entry price here is maximum. The cost of the device can be 3-4 times higher than its Chinese counterparts. The delivery time in the current geopolitical conditions has stretched to 6-9 months, which is unacceptable for many projects. In addition, original spare parts (plates and seals) are strictly tied to the serial number, which creates dependence on the vendor for the entire life cycle. However, for critical components, such as heat exchangers at nuclear power plants or in pharmaceuticals, where the cost of downtime amounts to millions per hour, European equipment remains the uncontested reliability standard.

Russian manufacturers (Ridan, Mashimpex, Danfoss (localization))

The Russian market of heat exchange equipment has evolved from simple assembly of imported components to a full production cycle. Modern factories, such as Ridan or Mashimpex, produce products that fully comply with GOST R 53686-2009. The key advantage of Russian multi-pass heat exchangers is adaptation to local conditions. The thickness of the metal frames is often increased, which increases resistance to water hammer, typical of worn-out utility lines. Spare parts are available from the warehouse within 2-3 days, and service engineers speak the same language as operators.

In the segment of multi-pass circuits, Russian manufacturers have learned to produce high-quality stamping, although the microrelief of the plates is sometimes inferior to top brands in turbulization efficiency. This is compensated by an increase in the heat exchange surface. The main risk is variability in rubber quality. Lots of seals may differ in service life. Our experience shows that at facilities with an aggressive environment (for example, acidic wastewater), Russian seals require replacement more often than their imported counterparts. But for heating and hot water systems this is the optimal choice in terms of price/quality/availability of service.

Chinese factories (APV (China), Jiangsu Province's own brands)

The Chinese segment is the most heterogeneous. There are giants like SWEP (owned by Danfoss), producing world-class brazed heat exchangers, and hundreds of small workshops offering dumping prices. In the category of collapsible multi-pass devices, China attracts with its low price and speed of production (2-4 weeks). Many factories have learned to copy the profile of plates of European brands, offering complete interchangeability in size.

The problem is in the details. The quality of AISI 304 or 316L steel may vary from batch to batch. We have seen cases where the stated plate thickness of 0.5mm was actually 0.42mm, which reduced operating pressure and accelerated corrosion. In multi-pass circuits, the manufacturing accuracy of distribution partitions is critical. If the geometry is violated, a flow of medium occurs between the strokes, and the efficiency drops. When ordering a Chinese multi-pass heat exchanger, be sure to request a chemical analysis report on the metal and an EAC or CE certificate of conformity issued by an accredited laboratory, not the factory itself.

It is worth noting that there are also specialized players on the market who occupy a unique niche between the mass segment and the premium class. A striking example is the companyWuxi Kaisheng Electric Power and Petrochemical Equipment Co., Ltd.. Unlike universal manufacturers, this company specializes in the development and manufacture of high-load heat exchange equipment for complex industries: oil refining, petrochemicals, seawater desalination and shipbuilding. Their approach is fundamentally different from typical solutions: instead of standard plate units, they focus on titanium shell-and-tube heat exchangers, high-pressure ASME models and units with corrugated tube bundles made of special alloys (marine brass C46400, copper-nickel alloys, nickel N06625).

This specialization makes their products an ideal choice for applications where conventional plate heat exchangers are ineffective due to extreme pressure, aggressive chemical environments or the need to work with sea water. Certification according to PED and ASME standards, as well as the use of materials with increased corrosion resistance, allow Wuxi Kaisheng equipment to operate for decades in conditions where analogues fail within a couple of years. If your project requires a custom engineering solution for heavy industry, rather than a template device from a catalog, it is worth considering the offers of such specialized manufacturers who can ensure process stability in the harshest conditions.

When choosing a supplier, don't just look at the price per unit area. A cheap Chinese device may require replacement of seals after a year, which eliminates the savings. The Russian version will give peace of mind for the service, but may be inferior in compactness. A European brand is an investment in reliability for decades, if the budget allows. For the specific tasks of heavy industry, specialized factories offering unique materials and designs become an alternative. Always request a reference list for facilities operating for more than 5 years and contact their main power engineers.

Critical errors in the selection and operation of multi-pass circuits

Even the most expensive heat exchanger will fail if errors are made at the design or installation stage. In our practice, there were several cases when new devices had to be sent back to the factory or the piping had to be radically altered due to a simple ignorance of the physics of the process. Here is a list of mistakes that cost the most.

Mistake #1: Ignoring cost asymmetries.
Often designers try to use a symmetrical design (1x1 stroke) for media with different flow rates. If the flow rate of heating water is 3 times less than the flow rate of heated water, in a symmetrical apparatus one medium will move at high speed, and the other will barely crawl. This leads to an imbalance: high hydraulic resistance on one side and low heat transfer coefficient on the other. The correct solution is to use a multi-pass design (for example, 2x1 or 4x1) to equalize the flow rates. Don't try to compensate by increasing the size of the machine; this will only inflate the estimate, but will not solve the hydraulic problem.

Mistake #2: Incorrect installation of partitions.
In multi-pass heat exchangers, distribution baffles (baffles) are installed between the frame plates. Their position must strictly correspond to the diagram indicated in the product passport. Installers often confuse the upper and lower chambers or place the partition in the wrong groove. As a result, the medium becomes locked inside one passage and does not pass into the next, or a mixing of flows of different temperatures occurs. The consequence is that the device does not heat up. Checking the correct assembly is only possible by monitoring the temperatures at each pipe before starting the main flow. If the temperatures do not correspond to the design program, disassemble and check the circuit.

Mistake #3: Saving on seal materials.
For multi-pass circuits, the load on the seals is higher, as they operate under more complex pressure gradients. An attempt to save money by purchasing universal seals instead of those specialized for a specific environment (oil, acid, steam) leads to rapid degradation of the rubber. Steam is especially dangerous. At temperatures above 160°C, conventional EPDM deteriorates within months. Viton (FPM) or combination seals are required. We have seen cases where steam leakage into the water circuit occurred due to the seal “floating” and losing its shape in the corner areas of the multi-pass package.

Mistake #4: Lack of coarse filters.
Multi-pass channels themselves are a dirt trap due to the complex flow path. If there is no filter at the inlet with a cell size of at least 0.5-1 mm (depending on the gap between the plates), the channels will clog very quickly. It is extremely difficult to clean the multi-pass bag mechanically due to the presence of internal partitions. Often a complete disassembly is required, which takes days. Installing a magnetic-mechanical filter in front of the heat exchanger is a mandatory requirement, not a recommendation.

Quality standards and certification: what to look for in documents

When working with industrial equipment, the words “high quality” mean nothing without supporting documents. In Russia and the CIS countries, the key safety marker is compliance with the requirements of the Technical Regulations of the Customs Union (TR CU 032/2013 “On the safety of equipment operating under excess pressure”). An EAC certificate is required for legal operation. However, the certificate itself does not guarantee durability.

Pay attention to compliance with international standards. ISO 9001 talks about the quality management system in the factory, but not about the characteristics of a particular insert. More important are industry standards such as API 662 (for the oil and gas industry) or TEMA. If the manufacturer claims compliance with GOST 15150 (version for moderate climates), make sure that the frame paint and sealing materials are really designed for the declared temperature range (-40...+40°C and above).

For multi-pass heat exchangers, a product passport with a detailed flow diagram of the media is critical. В документе должны быть указаны: материал пластин (с расшифровкой марки стали, например, AISI 316L, а не просто “нержавейка”), тип уплотнений, максимальное рабочее давление и температура для каждой из сред отдельно. Если в паспорте написано “давление 16 бар” без уточнения, для какой среды это актуально, такой документ не имеет ценности. В многоходовых схемах давление в разных камерах может отличаться.

Также стоит проверить наличие протоколов испытаний. Заводы-лидеры проводят гидравлические испытания каждого собранного аппарата давлением, превышающим рабочее в 1.25-1.5 раза. Требуйте копию акта гидроиспытаний с печатью ОТК. Отсутствие этого документа — красный флаг, сигнализирующий о возможном кустарном производстве.

Source: Text of Technical Regulations TR CU 032/2013

Экономическое обоснование: почему дешевое решение выходит дороже

Закупка теплообменного оборудования — это классический пример того, как скупой платит дважды. Давайте посчитаем реальную стоимость владения (TCO) на примере объекта мощностью 2 МВт. Разница в цене между качественным российским аппаратом и дешевым китайским “ноунеймом” может составлять около 30%. На бумаге экономия выглядит внушительно. Но давайте добавим эксплуатационные расходы.

Дешевые пластины имеют меньшую коррозионную стойкость. Через 3 года эксплуатации в воде с хлором они могут дать сквозную коррозию. Замена пакета пластин стоит почти столько же, сколько новый аппарат. Плюс простой системы на 3-5 дней во время ремонта. Для производственного предприятия простой линии стоимостью $10,000 в час обернется убытками в миллионы рублей, которые мгновенно съедят всю первоначальную экономию.

Второй фактор — энергопотребление. Неоптимальная многоходовая схема или зарастание некачественных пластин накипью из-за плохой турбулентности увеличивают потребление электроэнергии насосами на 15-20%. За 10 лет жизни аппарата переплата за электричество превысит разницу в цене при покупке. Качественный теплообменник с правильно рассчитанными ходами поддерживает высокий коэффициент теплопередачи (K) стабильно на протяжении всего срока службы, минимизируя затраты на перекачку среды.

Третий аспект — ликвидность. Брендовое оборудование (Alfa Laval, Sondex, Ридан) имеет высокую остаточную стоимость. Его можно продать б/у или использовать детали для ремонта других машин. Безымянный китайский аппарат через 5 лет превращается в металлолом, так как найти под него уплотнения или пластины становится невозможным. Принимая решение о закупке, считайте бюджет на 10 лет вперед, а не на момент отгрузки со склада.

Frequently Asked Questions

Как определить необходимое количество ходов для моего процесса?

Количество ходов определяется программным расчетом на основе соотношения расходов сред и требуемого температурного графика. Общее правило: если отношение расходов больше 3:1, требуется минимум 2 хода для меньшей среды. Если разница больше 10:1 — может потребоваться 4 или 6 ходов. Точный ответ дает только теплогидравлический расчет, учитывающий вязкость и допустимые потери давления. Не подбирайте количество ходов “на глаз”.

Можно ли переделать одноходовой теплообменник в многоходовой?

Да, большинство разборных пластинчатых теплообменников конструктивно позволяют изменить схему движения сред. Для этого нужно демонтировать пакет пластин, переставить распределительные перегородки в раме согласно новой схеме и собрать аппарат заново. Однако это возможно только если конструкция рамы и плит предусматривает такую возможность (наличие дополнительных пазов для перегородок). Уточните эту опцию у производителя перед покупкой.

В чем главная проблема обслуживания многоходовых аппаратов?

Главная сложность — правильная сборка. При наличии нескольких ходов критически важно соблюсти последовательность установки пластин и правильное расположение перегородок. Ошибка на одну позицию приведет к смешению потоков или блокировке циркуляции. Также затруднена механическая очистка внутренних каналов без полной разборки. Рекомендуется использовать химическую промывку (CIP) без разборки, если конструкция позволяет подключить промывочный контур.

Какой срок службы уплотнений в многоходовом режиме?

Срок службы зависит от температуры и химического состава среды. В стандартных системах отопления (до 95°C) качественные уплотнения EPDM служат 5-7 лет. В агрессивных средах или при высоких температурах (>140°C) ресурс снижается до 2-3 лет. Многоходовой режим сам по себе не сокращает жизнь уплотнения, если нет пульсаций давления и гидроударов. Регулярная подтяжка болтов в первый месяц эксплуатации продлевает срок службы.

Итоговые рекомендации и план действий

Выбор многоходового теплообменника — это инженерная задача, требующая баланса между гидравликой, теплотехникой и бюджетом. Не существует “лучшего производителя” для всех случаев. Для критически важных процессов с высокими температурами и давлением выбирайте проверенные европейские или топовые российские бренды с полным комплектом сертификатов. Для второстепенных контуров или временных схем можно рассмотреть качественные китайские аналоги, но только после тщательной проверки металла и геометрии. Для экстремальных условий нефтегазовой отрасли или работы с морской водой целесообразно обратиться к специализированным производителям, таким как «Уси Кайшэн», предлагающим решения из титана и особых сплавов.

Помните, что количество ходов — это инструмент настройки производительности. Используйте его грамотно: выравнивайте скорости потоков, контролируйте перепад давления и не забывайте про фильтрацию. Ошибки в проекте многоходовой схемы исправляются только дорогой заменой оборудования или серьезной модернизацией насосной группы.

Если вы столкнулись со сложностями в подборе оборудования или сомневаетесь в корректности предложенной коммерческим отделом схемы, не рискуйте бюджетом проекта. Наши эксперты готовы провести независимый аудит вашего технического задания и предложить оптимальное решение, проверенное годами эксплуатации в реальных условиях.

Contact us todayдля получения детального расчета и консультации по выбору надежного многоходового теплообменника под ваши задачи. Мы поможем избежать ошибок и подобрать оборудование, которое прослужит долго.

Узнайте больше о наших решениях для промышленности в разделепромышленные теплообменникиили изучитекейсы успешной модернизации.