How to Clean and Maintain Your Heat Exchanger

换热器are designed to optimize heat transfer from one gas or liquid to another during processing andClean-in-place（CIP）。从污垢或老化的降低的热交换器性能导致额外的操作和能源成本，以补偿目标温度的间隙。因此，热交换器的清洁和维护对于保持系统有效地运行是重要的。Regular maintenance ensures equipment is in working condition and helps prevent emergency repairs.清洁热交换器的成本与损耗的成本相比，热交换器需要出现未划分的关闭。

Product or chemical deposits on heat-transfer surfaces weaken an exchanger’s heat-transfer capacity and must be cleaned away regularly to maintain high performance and prevent disruption of processing. Heat exchanger fouling, or the unwanted accumulation of deposits on heat-transfer surfaces, can result in several costs:

1. Production loss from shutdowns
2. Maintenance costs for removal of heavy fouling deposits
3. Replacement of plugged equipment

影响热交换器性能的沉积物发生在污垢和老化。

• Fouling is the freshly deposited material on contact surfaces
• Aging occurs close to the surface of heat transfer components

Three key factors play into the frequency and degree of fouling:

• Fluid temperature
• 液体的性质
• 流体速度

How do I know when to clean a heat exchanger?

You can tell when it’s time to clean your heat exchanger when the exchanger doesn’t achieve the correct product temperatures for heating or cooling。不正确的温度是由降低温度转移的板表面污垢产生的。

您也可能看到高于指定的压力下降，因为污垢正在收缩通道通道并增加流体速度。

清洁（CIP）

清理(CIP) equipment can clean plate heat exchangers without disassembly. CIP is a combination of time, temperature and concentration. CIP provides bothchemicaland mechanical cleaning to the heat exchanger. If system configuration prohibits CIP, operators must perform manual cleaning.

热交换器的CIP清洁通常包括若干目标：

• 清洁石灰矿床
• 钝化表面以减少对腐蚀的易感性
• 在排水前中和清洁化学品。

The importance of flow rate

The proper flow rate ensures effective mechanical action of fluids during cleaning. Some manufacturers recommended approximately 1 ft/sec velocity across heat exchanger plates, but requirements vary by manufacturer.

The flow rate during the cleaning of the product side should always be at least the same as the production’s flow rate.在某些情况下可能需要增加的流速 - 例如，在乳灭菌和粘性液体或含有颗粒的液体的处理中。

Recommended limits for cleaning solutions

•5％由体积腐蚀性最大为70°C

• 0.5% by weight acid solution at a maximum of 70°C

Manufacturers can provide more detailed information about cleaning and sterilization for specific equipment.

Basic chemical cleaning process

Chemical cleaning in CIP offers several advantages:

• 更快的清洁过程
• Less labor intensity
• Cleans components that mechanical cleaning can’t do

操作员通常在CIP中的化学清洁过程中遵循四个步骤：

1. Alkaline clean: removes build-up of organic materials
2. Rinse: generally completed with a high-flow water flusher to remove loose debris and remaining residue from the alkaline step
3. 酸洗：有助于更深入地溶解和软化污垢材料
4. 最后冲洗

选择正确的清洁剂

Selecting the right chemicals for cleaning heat exchangers is important to ensure proper cleaning and to avoid damaging exchanger components. For example, the following solvents and other cleaning agents can damage heat exchanger plates and gaskets:

• Ketones such as Acetone, Methyletylketone, Methylisobutylketone
• Esters such as Ethylacetate, Butylacetate
• Halogenated hydrocarbons such as Chlorothene, Carbon tetrachloride, Freons
• Aromatics such as Benzene, Toluene

Cleaning agents to use, by purpose

Incrustation, scaling

Cleaning incrustation or scaling is a process of removing calcium carbonate, calcium sulphate, or silicates from plate surfaces。Cleaning agents must be compatible with both the plate metal and the composition of gaskets.

In the case of titanium and stainless steel plates, never use hydrochloric acid. Also, never use water of more than 300 ppm of chlorine during the preparation of cleaning solutions. Chlorine, commonly used as growth inhibitor in cooling water systems, reduces the corrosion resistance of stainless steels, includingHastelloy., Incoloy, Inconel and SMO.氯削弱the protection layer of these steels, making them more susceptible tocorrosion attacks而不是他们应该是。在每种情况下，无法避免非钛设备的氯化，您必须咨询您的设备供应商。

Removing sediment

Sediment most commonly consists of metal Oxides, silt, Alumina, and Diatomic organisms and their excrement. Sediment accumulates because heat releases minerals and other particles from fluids during processing cycles, and those settle and deposit on heat transfer surfaces.

您不应该使用不锈钢或钛板使用盐酸，因为酸导致一般腐蚀，点蚀和应力腐蚀裂缝。

Removing biological growth

当使用热交换器增加加工食品的温度时，可以发生生物生物生物生物生长，如细菌，线虫和原生动物。去除生长需要相同的注意板和垫圈组合物，以结合。

Cleaning a Shell and Tube Heat Exchanger

Shell-and-tube heat exchangers have comparatively low internal fluid velocities so are more susceptible to fouling than plate heat exchangers.为了保持有效的操作，请保持热交换器的传热表面清洁。

Cleaning chemicals depend on the same variables for a板材和框架热交换器, and cleaning compounds must be compatible with the metallurgy of the heat exchanger.

在所有清洁过程中，操作员必须使用适当的防护设备，例如安全靴，安全手套和眼睛保护，以避免受伤。

Regasketing

For clip-on gaskets, the regasketing process is as easy as taking the current gasket off and clipping a new one on.

For glued gaskets

1. Remove the old gasket
2. 清洁密封表面，直至没有异物，如脂肪，油脂或其他土壤。
3. 查看the new gasket and remove rubber residual before attaching.
4. Clip on a new gasket or apply glue as required by gasket type
5. Perform heat treatment to set the glued gasket according to manufacturer’s instructions.

The new gasket is wrongly positioned if it rises out of the gasket groove or is positioned outside the groove.

Why does my plate heat exchanger leak?

When closing a heat exchanger after maintenance, the plate pack dimension must be within the manufacturer’s specified tolerance to ensure proper operation. Overtightening can damage the plates, while under tightening can cause the plates to leak.

插图：根据需要紧固螺栓以维持正确的尺寸A.均匀地拧紧四个螺栓（1），（2），（3），（4）直到达到尺寸A.在紧固期间测量尺寸A.