常见问题

热传递技术是一门复杂的学科,此处列出了一些最为常见的有关换热器和油冷却器性能、设计以及操作方面的问题。

我们希望您能在以下列表中找到问题的答案。但是,如果没有,您也可以点击“联系我们”页面,填写并发送问询表,我们将直接回答您的问题。

 

换热器是一种能够将热能从一种液体或气体传递到另一种液体或气体的装置,在此过程中这两种液体或气体并不相互接触。一台标准管壳式换热器由一个外壳或管体以及位于其中的管组组成。冷水穿过管组,而热水/气体则在管组外部流动,以使其热量传递到管组内部的冷水中。

加热游泳池就是一个很好的例子。大多数泳池水通常是通过锅炉进行加热的,使用天然气、液化石油气或生物质作为能源。从理论上来说,加热泳池最有效的方法是使池水直接通过锅炉循环。但是如果这样做,池水中用于安全保障所使用的化学物质会迅速腐蚀和损坏锅炉内的重要部件,导致其过早失效,并产生不菲的更换成本。

通过使用换热器作为锅炉水回路和池水回路之间的“界面”,能够保护锅炉免受损坏,并且使池水迅速加热到所需的温度。当冷的池水通过换热器中央的“管芯”,而热锅炉水在管芯周围循环时,热能就被传递到了池水中。

了解更多关于使用Bowman换热器的应用实例

内燃机、变速箱及传动系统等机械设备通常依靠机油来润滑其内部传动部件,以使其能够自如地运转,同时减少金属表面的磨损。

除用于润滑外,发动机油还能起到冷却剂的作用,以排出机械设备中的余热。例如,热的发动机将热能传递给机油,之后,机油在换热器(也称为油冷却器)中循环,由气体或水进行冷却。

各类机油都有相应的建议工作温度范围,如果高于此范围,油的黏度会降低,从而导致其润滑质量下降。如果过多的热量持续积聚,润滑油的润滑能力将明显降低,在极端情况下,其黏滞度可能丧失,从而造成机械部件过热,导致其过早磨损。在状况严重时,这甚至可能导致灾难性的部件故障。

这种情况通常出现在设备长时间高速运行或者环境温度较高的气候条件下。此时,在润滑系统中增加一个油冷却器能够减少多余的热量,降低油温,使其保持在合理的工作范围内,以保护设备并延长其使用寿命。

对于风冷或水冷油冷却器的选择则取决于设备的应用和运行条件。

Bowman油冷却器为水冷“管壳式”设计,性能稳健可靠、应用广泛。了解更多有关Bowman油冷却器的信息

管壳式换热器在使用期间需要多次清洁。在淡水和海水冷却介质中都含有大量的矿物质和污染物,随着时间的推移,这些矿物质和污染物会积聚起来,限制水流通过管芯,降低其流速,从而导致热传递效率大幅降低。

好消息是,Bowman管壳式换热器比许多其他类型的换热器都易于清洁,以下为基础清洁指南:

  1. 拆下换热器端盖即可看到管芯,可以将其从外壳(或管体)中取出。
  2. 之后, 可以使用手持式冲洗软管或喷枪清洗管板和外管。有条件情况下也可以使用蒸汽清洁器。
  3. 可使用小直径的刷杆或管刷清洁每根管道,以清除顽固沉积物。
  4. 如果管道积垢严重,可以使用清洁剂或化学品。让清洗介质停留足够的时间之后,再使用大量水冲洗。注意:务必检查所使用的清洁剂是否适用于管组材质。
  5. 使用清水彻底冲洗管芯,以清除所有清洁化学品/清洁剂残留,如有必要,应对清洁液进行中和。
  6. 将管芯重新装回管体中,将端盖按照其原始方向重新安装并按照建议的扭矩值拧紧。注意:清洁后,必须使用新的“O形”密封件,以确保接口的水密性。

有关Bowman换热器或油冷却器的保养和维护的详细信息, 请下载我们的“安装、操作与维护指南”

Many water cooled internal combustion engines (ICE), can be adequately cooled, simply by pumping the engines coolant through an air cooled radiator.

Cooler ambient air is drawn into and through the radiator by a cooling fan, transferring heat from the engine coolant as it is pumped through the radiator.

But there are applications where air cooling is either less efficient or not an option for an ICE. This could be due to insufficient air flow, or ambient air temperatures being too high, and in these situations, water cooling is a proven solution.  Moreover, replacing the radiator with water cooled heat exchangers can save valuable space and considerably reduce noise.

Installing water cooling is quite straightforward as instead of a radiator, a heat exchanger, usually of ‘shell and tube’ design, is installed into the engines cooling system.

The heat exchanger has two circuits; one will be connected to the engines cooling circuit and the other connected to a source of cool water, which could be seawater for a marine engine or fresh water for applications such as irrigation systems, power generation, fire protection or automotive engine testing.

The cooling water is pumped through a central tube core in the heat exchanger, whilst the engines coolant flows over and around the outside of the tubes, transferring heat from the engines coolant circuit to the cooling water as it flows through the unit.

Whilst there are many heat exchangers suitable for cooling engines, Bowman’s Header Tank units are particularly successful due to the design, which incorporates and integral expansion chamber above the tube core. This eliminates the problem of air pockets or air locks getting into the cooling stream. There is also has a special de-aeration feature, plus pressurised filler cap, making integration very much easier. For more information on Bowman Header Tank Heat Exchangers

As their name suggests, hot tubs require a lot of heat to achieve and maintain the 38°C to 40°C water temperature they usually run at.

Most hot tubs are supplied as standard with an electric heater already installed. This usually takes many hours to heat a typical 1,400 litre hot tub from ambient water temperature to normal operating temperature, and as electricity is one of the most expensive ways of heating, it’s not surprising that many users find their electricity costs rise sharply!

A more efficient solution is to heat the hot tub from an external heat source, such as a gas boiler. Usually, this can be done by connecting pipework from the hot tub to the boiler, in a similar way to adding a new radiator to a new room in a home.

The only difference is the hot tub requires a heat exchanger to act as an interface to keep the pool and the boiler water separate from each other. Installing the heat exchanger into the pool water circuit and connecting to the boiler is straightforward, though a plumber may be required to install.

Once the hot tub is being heated from the house boiler, many users notice how much quicker the water temperature increases and in many cases, the hot tub can be ready to use in just 2 -3 hours of heating, which is a real bonus, as it significantly reduces the energy used and, as gas heating costs are much lower than electricity, energy costs are significantly reduced too!

Bowman has been one of the pioneers in providing hot tub heating via heat exchangers and have a comprehensive range of products for this specific application. For more information on Bowman Hot Tub Heat Exchangers

Although electric propulsion for marine vessels is still relatively new, it is experiencing significant growth and development as the industry seeks to reduce marine CO² emissions.

Currently, many system manufacturers are choosing shell and tube heat exchangers for their electric propulsion systems for the following reasons:

Coolant Flow

In many electric and hybrid marine applications, the coolant flow around the electrical components is usually much lower than the seawater cooling flow. Shell and tube heat exchangers are much better at handling the imbalance of coolant velocities than other types of heat exchanger, such as plate types.

Easier integration

The compact design of Bowman shell and tube heat exchangers, combined with the lighter weight of their titanium units, makes them easy to integrate into the system design.

Reliability

With rising pollution levels, Bowman shell and tube heat exchangers are less affected by blockages from sea borne debris, compared to plate types.

Bowman manufacture a comprehensive marine heat exchanger range for electric and hybrid applications and are already specified by some of the leading manufacturers and system integrators.  For more information on Bowman Electric & Hybrid Marine heat exchangers

Intercoolers (also known as Charge Air Coolers) improve the combustion efficiency of engines fitted with forced induction (either a turbocharger or supercharger) increasing the engines power, performance and fuel efficiency.

Turbochargers compress incoming combustion air, which increases its internal energy, but also raises its temperature. Hot air is less dense than cool air, thus its combustion efficiency is reduced.

However, by installing an intercooler between the turbocharger and the engine, the incoming compressed air is cooled as it passes through the intercooler, restoring its density to give optimum combustion performance.

An intercooler acts as a heat exchanger, removing the heat generated during the turbochargers compression process. It does this by transferring the heat to an other cooling medium, which is usually either air or water.

Air cooled intercoolers

These are similar in principle to a car radiator in that cool air is drawn through the fins of the intercooler, transferring heat from the compressed turbo air to the cooler air.

Water cooled intercoolers

Where air cooling isn’t an option, water cooled Intercoolers offer a highly efficient solution. Usually based on a ‘shell and tube’ design, cold water flows through the central tube ‘core’, whilst the hot charge air flows around the tubes, transferring its heat as it travels through the heat exchangers.

Bowman manufacturer a wide range of water cooler Intercoolers (Charge Air Coolers), suitable for both marine and land based stationary engine. For more information on Bowman Charge Air Coolers

A CHP (Combined Heat and Power) unit generates electrical power and heat from a single energy source.

There are three primary components within a CHP unit, starting with the Prime Mover, (usually a reciprocating engine) that creates the motive power to drive the Electrical Generator. The final component is the Heat Recovery system, which comprises of single or multiple heat exchangers installed on key areas of the engine, to recover waste heat produced as a bye-product.

In an engine powered CHP unit, around 30% of the fuel used gets converted to electrical power. At the same time, around 50% of the fuel energy gets converted to heat. Without heat recovery, this valuable and highly usable energy stream would be lost to the atmosphere, wasting around half the cost of all fuel used to power the generator. By recovering this heat energy, the generating sets overall efficiency is improved to around 80% – even more in some installations – making CHP a highly efficient energy solution.

Recovered heat can be used for a wide range of domestic, commercial or industrial uses, including space heating and hot water, process heating, as well as cooling, or even generating more power!

Heat can be recovered from the engines exhaust stream, plus its cooling, lubrication and induction systems, using heat exchangers.

Bowman manufacture a comprehensive range of CHP heat recovery heat exchangers for exhaust gas, engine and induction cooling. For more information on Bowman CHP heat exchangers

Combined Heat and Power (CHP) is an extremely efficient method of generating electrical power and heat energy, from a single source.

Most ‘off-grid’ electricity is produced using an engine driven gen-set, usually powered by diesel or gas fuel.

However a typical gen-set, producing electricity only, is often only around 30% efficient.

That’s because only around 31% of the fuel used is converted to electrical power. The remaining 69% is lost throughout the operating cycle.

The largest element of energy loss is heat –  around 49% in total, so by recovering it, a valuable ‘free’ energy source is obtained, which also boosts the gen-sets overall efficiency to around 80%!

Heat exchangers are the most effective solution for recovering waste heat energy, as they convert it to hot water, which can be used for space heating, and hot water in residential or commercial buildings, industrial process heating, generating more power or even cooling via a chiller.

Heat can be recovered from virtually every area of the engine, including the exhaust stream, the cooling and lubrication systems, plus the induction air system.

Bowman manufacture a comprehensive range of CHP heat exchangers enabling customers to convert their gen-set into a highly efficient CHP system.

There are a number of factors to consider when projecting the life of a marine oil cooler.

For example, has the correct product been selected for the cooling requirement?

Has it been installed and commissioned correctly?

Is the velocity (or flow rate) and pressure of the cooling medium within manufacturers recommendations?

Has the unit been maintained and serviced in line with manufacturers requirements?

Assuming all the of the above questions (and possibly a few more) have been correctly addressed, there is no reason why a good quality marine oil cooler, from a well known, reputable company such as Bowman, shouldn’t last for more than 20 years.

But to achieve this, it’s vital that the unit is correctly specified, installed, commissioned and maintained.

For example, on marine oil coolers fitted with Cupro-nickel tube stacks, it is vitally important to ensure the copper-nickel alloy tubes are ‘conditioned’ correctly, to enable the thin layer of natural protective film to form on the tube surface, to provide long term corrosion protection.

Additionally, if the manufacturers recommended water flow rate is exceeded, high velocity seawater entering the oil cooler can quickly erode the tubes and tube plates, leading to premature failure, so following the guidelines is critical!

And the well documented rise of plastic waste in our oceans, means that in addition to having adequate filtration of the incoming seawater, it’s also really important to inspect and clean an oil cooler regularly, to maintain its performance and extend the life of the unit!

The good news is that if looked after correctly, a marine oil cooler can operate reliably for decades.

In fact Bowman often hear of instances where their marine oil coolers have been working for more than 40 years!

Bowman manufacture a very wide range of oil coolers to suit most marine applications and have a computer based selection programme, to recommend the correct unit for the application.

油冷却器专门用于消减车辆、机器以及机械设备中润滑油产生的过多热量。此类冷却器包括-油或气-油型换热器。

针对不同的温度范围和工作条件,润滑油品类各有不同。为确保润滑油能够对相应的机械设备起到保护作用,应始终使其在指定的温度范围内工作。

如果温度过低,润滑油将会变稠,使其难以润滑运动中的机械部件。过热时,油的黏度将开始下降,导致部件过早磨损,最终形成设备故障。

问题在于,移动中的金属部件会产生大量的热量,这些热量会被传递到润滑油中。此时,在润滑油回路中增加一台油冷却器,可以很好地控制机油的温度,使其始终保持在正确的范围内。

油冷却器可以采用风冷或者水冷,这取决于应用的性质。Bowman为公路/非公路车辆、建筑工程以及相关设备生产各种水冷“管壳式”油冷却器,用于冷却变矩器、自动变速器和发动机等重型应用润滑油。

了解更多关于Bowman油冷却器的信息。

油冷却器旨在消减车辆、机器及机械设备的润滑油中产生的过多热量。例如,热的发动机将热量传递给机油,之后,机油通过换热器(也称为油冷却器)进行循环,由空气或水对其冷却。

油冷却器通过使用冷却介质(通常是空气或水)将机油中的热量传递到介质中来实现冷却。在此过程中,油和冷却介质不会直接接触。

举例来说,风冷式油冷却器通常看起来类似小型车用散热器,通过使机油通过翅片管达到冷却目的。此时,进入冷却器的空气在管组周围流动、带走热量。

对于许多应用来说,空气冷却并不合适,此时,水冷是合适的解决方案。在此类应用中,管壳式油冷却器的使用非常普遍,冷却液通过油冷却器中央的“管芯”,而机油在管周围流动,带来极为有效的热传递。

Bowman生产了一系列水冷管壳式油冷却器,用于变矩器、自动变速器和发动机机油冷却。了解更多关于Bowman油冷却器的信息

在冷却介质和被冷却液体之间存在较大温差的情况下,与板式换热器相比,管壳式换热器通常是更具成本效益的冷却解决方案。这是由于板式换热器内的流动通道较小,易造成大量湍流,导致装置内的高压降。

顾名思义,板式换热器由一系列薄金属板组成。这些金属板片通常由不锈钢制成,板片上均有精细的压制形状。为了确保装置的防水性,金属板片之间夹有橡胶垫圈,在一个刚性框中被压紧,形成冷热流体交替的平行流道布局。

相比之下,管壳式换热器由两个主要部件组成:外壳(或管体)和壳体内的管芯(或管组)。冷却介质穿过管芯,而热的流体通过入口进入壳体,流经一系列挡板并围绕管芯周围流动,然后通过出口离开管体。为了获得最大的热传递效率,热流体和冷流体以“逆向流动”方向通过换热器。了解更多关于逆向流动的信息

虽然板式换热器可以非常紧凑,并且能够增加尺寸,但是一旦冷却要求发生变化,其维护成本将比同等的管壳式换热器高。通常,橡胶垫圈会老化、硬化,需要每两年更换一次。这是一项耗时且昂贵的工作,换热器必须长时间停用。此外,对于泄漏的检测可能更为困难,需要技术熟练的人员来承担这项工作。并且,由于换热器内水流阻力较大,结垢的可能性增加,也会降低装置的效率。

相比之下,管壳式换热器极易维护。拆下端盖就会看到管芯,可以将其取出进行清洁和日常维护。优质的管壳式换热器——如Bowman换热器——的传热效率非常良好,并且装置本身坚固耐用,能够带来长久的使用寿命和耐用性。管壳式换热器还可应用最苛刻的冷却介质,包括海水以及富含矿物质或受污染的水。

了解更多关于Bowman管壳式换热器系列的信息

 

如果您的泳池无法加热到所需的温度,可能有几方面原因。以下检查列表将帮助您找寻问题所在:

1: 能量是否充足?
无论使用燃气锅炉、太阳能电池板、热泵还是其他热源来加热泳池,重要的是,用于加热的能量是足够的。

2: 换热器是否合适?
一个常见的误区在于人们常常认为换热器越大,其加热泳池的速度就越快!然而,事实未必如此。适合泳池所用的换热器品类众多,在设计、性能和换热效率等方面均有很大差异。

3: 加热系统是足够的,但是游泳池还是不能加热!
在换热器将热能传递到池水中时,热水流体和冷水流体的流速至关重要。如果热水流速过低,可用的热量将无法通过换热器。不过,池水的流速也同样重要。

4: 如果以上所有都已经做到了……
即使所有设备均恰当合适,系统的其他部分仍有可能产生问题,需要进行检查。

5: 总而言之……
本文是对各详细文章的概括, 旨在帮助大家发现池水加热和换热器的问题。请在此处阅读完整文章

了解更多关于Bowman泳池换热器的产品信息

 

大多数热水浴缸均配有一个一体式电热水器,根据浴缸的容量,其输出功率通常在3kW左右。此类热水器通常每小时可将水温提升1-2°C左右,因此,如果使用环境温度的水,其加热过程最高可达24小时。

为了解决这个问题,一些用户使用来自附近锅炉的预热水(25℃)来加热浴缸,但考虑到热水浴缸通常需要38-40℃左右的温度,按照电加热器的性能,还需要6到10个小时才能达到理想温度。

如此漫长的加热时间让很多业主产生了高度不满,他们希望自己的热水浴缸加热时间能够比一般的加热系统提供的时间快得多。

因此,许多热水浴缸用户,特别是商业领域的用户,正转向采用一种新型的加热系统,那就是使用外部锅炉,并且连接Bowman换热器。其优点包括显著减少加热时间(通常,使用环境温度水需3-4小时,使用预热水需1小时),并且,与电加热相比,能够大幅降低能源成本。

了解更多关于Bowman换热器加热热水浴缸的详细信息

 

大多数热水浴缸都配有一个一体式电加热器,根据水容量的不同,输出功率通常在3kW左右。然而,最近,通过外部锅炉使用燃气加热的趋势日渐盛行,因为与加热相比,这种方式加水的速度更快。这意味着当您不使用热水浴缸时,可以将其保持在一个较低的温度,甚至可以完全关闭加热器。因为,当您准备使用热水浴缸时,无需花费很长时间便可达到所需温度。

而采用电加热器加热浴缸所需的时间很长,在使用冷水的情况下通常长达24小时。为了加快加热速度,一些业主采用锅炉热水“预先注入”浴缸,但即使这样,也需要再加热6到10个小时,才能达到所需的38-40°C。

虽然许多家庭用户为忍受这种不便做好了准备,但对于度假公园之类的商业用户来说,这种情况是无法接受的!

在假日住宿预订中,对热水浴缸的需求已经大幅上升,目前已成为位列第二的客户需求设施。为满足这一需求,度假区必须寻找一种更快的方式来加热浴缸水,因为客户更迭期间时间紧迫。一般来说,在新客人到来之前,只有大约4-5个小时的时间进行浴缸排水、清洁、重新注水和加热。

解决方案相对简单——使用一个燃气锅炉之类的外部热源,简单地旁通热水浴缸电加热器。为了实现这一点,需要使用换热器将锅炉水的热量传递到浴缸水中。这和大多数游泳池加热的原理完全相同,只是规模较小。

为此,Bowman开发了一种超紧凑型换热器,能够安装在热水浴缸管道系统中,最终,采用冷水加热浴缸需3-4小时,采用预热水加热则只需1小时左右。

此外,还有另一个好处。电加热通常较为昂贵,通过改用燃气锅炉加热后,根据众多用户的反馈,能源成本得到了大幅降低。之前,一些用户的单个浴缸加热成本高达500英镑!

度假区如何从改用燃气加热中受益

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在管壳式换热器中,冷却介质通常会穿过中心的“管芯”,冷却流经管芯周围的热油、水或空气。两种流体流经过换热器的方向可以是“平行流动”或“逆向流动”。

平行流动意为待冷却的流体以与冷却介质以相同的方向流过换热器。虽然这种布局能够提供冷却,但有局限性,并且可能形成换热器内部的热应力,因为装置的半边温度将明显高于另外半边。

使用逆流冷却时,进入冷却器的冷却介质在与“热”流体反向流动时会吸收热量。在通过换热器时,冷却介质会被加热,当更冷的介质持续进入换热器时,其将吸收更多的热量,与平行流动所达到的温度相比,逆向流动实现的温度要低得多。

在通过整个换热器时,冷却介质和被冷却流体之间的平均温差也更为均匀,从而降低了热应力。

根据流速和温度的不同,逆流换热器的换热效率可以提高15%,因此换热器的体积可以更小,以节省空间和资金!

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泳池换热器的工作原理是将热能从热水回路传递到泳池冷水回路,而这两种流体并不直接接触。

大多数泳池水都是通过锅炉加热的,使用诸如天然气、液化石油气或生物质等燃料作为能源。理论上,加热池水回路最有效的方法是将其直接连接到锅炉。

如果这样做,为保障水池安全性而添加到池水中的化学物质和矿物质会迅速腐蚀和损坏锅炉内的重要部件,导致其过早失效、产生不菲的更换费用。

然而,通过使用换热器作为锅炉水回路和池水回路之间的“界面”,既可以保护锅炉不受损坏,又能够使池水迅速加热到使用所需的温度。

管壳式换热器由于其性能高效、易于维护,在泳池的应用中非常普遍。在“壳体”内的管组被称为“管芯”,在换热过程中,池水将从管芯中单向通过。

同时,来自锅炉的热水在由众多管道组成的管芯外部循环。锅炉水与池水以相反方向流动,将其热量传递到池水中,然后再循环回锅炉进行再加热。

两个水回路都在连续的加热循环中运行,直至泳池水整体达到所需的温度 (通常在28-30°C左右)。

Bowman生产的泳池换热器品类全面,应用于从温泉池、热水浴池至奥运会规格游泳池的多种场合。

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选择正确的换热器对于确保池水快速加热到所需温度非常重要。确定游泳池换热器尺寸时要考虑的主要问题有:

  1. 游泳池的大小、水容量是多少?换热器的大小取决于池水容量,因此,如果您的游泳池为180m³ (39500gal),那么用于加热80m³ (18000gal) 游泳池的换热装置就毫无用处了。
  2. 怎样加热池水?通常选择锅炉或可再生能源进行加热。如果采用的是可再生能源,请选择专为太阳能电池板或热泵加热低温水而设计的换热器,因为这些设备将游泳池加热到所需温度需要的能量较少。
  3. 锅炉水温。然而,大多数池水由锅炉加热,那么锅炉水温是多少?通常在80°C到85°C之间——这是泳池加热的理想温度。有些锅炉温度较低,约为60°C。因此,使用82°C的水时,一台换热器可传递110kW热量,同时有效加热180 m³的池水。但是,如果锅炉水温只有60°C,可用于传递的热量会减少40%以上、下降至60kW左右,因此,需要更大的换热器才能使池水达到理想温度。
  4. 水的流速是多少?流速对于换热器将热量传递到池水至关重要。如果热水流速过低,可用的热量将无法通过换热器。然而,池水的流速同样重要。人们常常认为进出换热器的水之间产生较大的温差是很重要的。如果换热器出水口的管道温度明显比入水口的温度高,他们会很高兴。
    但事实是,这实际上是降低了热传递的效率!因为池水流速太低,水在换热器中停留的时间过长,使得更少量的水被加热到了更高的温度。然而,在池水的流速增加后,换热所需的时间就会减少,即使通过换热器的池水温度仅略微升高(例如1.5°C),也会对整个池水的加热效率产生更大的影响。

有关换热器选择的更多信息,请参阅文章 “为什么我的泳池升温不快?”