How to Choose a Heat Exchanger

Just as the name implies, a heat exchanger is a piece of equipment that transfers heat, usually between one or more fluids. Heat exchangers are ideal devices that are commonly used in refrigeration, air conditioning units, power stations, sewage treatment, gas processing and even when it comes to regulating engine cooling in internal combustion engines.

Heat exchangers are classified by how they operate, however they’re typically categorized into three main types – shell and tube heat exchangers, compact heat exchangers and air cooled heat exchangers. The shell and tube heat exchanger type is the most popular, as it’s estimated that over 50 percent of all heat exchangers currently in operation today are of this variety. However, in some applications, it makes more sense to go with one of the other types. Before we get into more concrete advice on how to choose a heat exchanger, it’s first important to note the major differences between the three main types.

Main Types of Heat Exchangers

  • Shell and tube: As we noted, these are the most popular type installed – and they’re also the best understood. They’re versatile in the service that they can provide across a span of applications and work at a wide range of pressures and temperatures. Shell and tube exchangers are also made to last, and are normally able to withstand rugged environments.
  • Compact: Compact heat exchangers are a more affordable option, available in a wide variety of configurations. They enable high heat transfer coefficients (up to 3 times greater than what is permitted by a shell and tube exchanger) and also permit high temperature crosses to be achieved. What’s more is that, fitting to the name, these heat exchangers have a small footprint and are easier to be installed in confined spaces.
  • Air cooled: Air cooled heat exchangers are ideal options for applications that involve cooling water or applications where cooling water is expensive. A big benefit of these types of heat exchangers is that they have low operating costs and normally require less maintenance compared to other models. However, they’re considered the most expensive of all heat exchangers.

Choosing a Heat Exchanger

Now that we’ve covered the main types of heat exchangers, you can probably already get an idea of which one is correct for your application. But it’s also worth noting that just because the shell and tube exchanger is the most popular doesn’t mean that it’s a sure-fire fit for your application. That’s right, the heat exchanger that you choose should largely be dictated by the application. Failure to choose it in this manner can lead to poor plant performance, operation issues and even full-blown equipment failure. But aside from deciding what type of heat exchanger is ideal for your application, there are other factors to consider. Here’s a closer look:

  • Total lifecycle cost: The total lifecycle cost of a product, let alone a heat exchanger, includes the initial purchase price, the installation cost, the operating cost and maintenance costs until the product is not used anymore. So, for instance, if a company decides to purchase a compact heat exchanger because they’re generally cheaper and can be installed easier, the may have to weigh the fact that it may cost more to maintain due to the thin nature of wall thicknesses of compact models. Conversely, while shell and tube heat exchangers are generally more expensive, their rugged build helps them stand up better over time. Air cooled exchangers have a high initial purchase price, but are relatively inexpensive to operate and maintain. These are all factors that must be considered when weighing total lifecycle cost.
  • Application: What role does your heat exchanger need to help perform? Boiling? Condensing? Something else? This is a huge consideration, as the application will, in most cases, dictate the type that you need to best accomplish the task at hand.
  • Operating pressures/temperatures: What type of temperatures and pressures is the heat exchanger intended to work with? That’s a big question to ask, as it will dictate your selection.
  • Durability: Depending on the application, the heat exchanger may have to do its job in some very demanding conditions. If that’s the case, it’s important to consider an exchanger’s durability and reliability. For instance, as we noted above, shell and tube exchangers are usually very rugged in build and able to stand up well in demanding environments, compared to compact exchangers, which are normally made to be less durable.
  • Footprint: What type of space are you working with? Is it a large space? Or do you need something that will fit in a confined space? That will also largely dictate your heat exchanger selection. Compact models are small and able to fit in a more confined area, while air cooled models require a large space. Shell and tube heat exchangers are on the larger side, but generally more versatile in terms of installation space required.
  • Accessibility: How easily will the heat exchanger be able to be reached for the likes of cleaning and maintenance? Despite the reputation of some heat exchangers being more durable than others, routine maintenance is almost always key to longevity.
  • Operating specs: This goes along with application, but it’s important to know exactly what you need your heat exchanger to do, and what temperatures and pressures it needs to be able to withstand in order to do it. Operating specifications are a big reason why the shell and tube heat exchangers are the most popular – they’re able to work across the widest variety of temperatures and pressures.
  • Other considerations: Other considerations on how to choose a heat exchanger include things like the fouling characteristics of the fluid, any utilities that are available (i.e. cooling towers, steam, etc.), potential for future expansions and the impact that the heat exchanger has on the overall environment.

Another big consideration is cost, as heat exchangers aren’t cheap, especially those of the air cooled variety. Though essential to the operations of many facilities worldwide, heat exchangers may put plant managers in a bind if one of their units prematurely fails or needs extensive repair. If replacement isn’t in the budget, what can you do? That’s where a credible site like Bid on Equipment can help, as the service provider collects pre-owned industrial equipment and puts it back on the market for sale. Think of it like getting a functional, like-new product at a used price. It’s these lower price points that can do wonders for a company.

For more information on heat exchangers, and to browse Bid on Equipment’s selection of this equipment, contact us today.

 

The Different Types of Packaging Wrappers

Packaging is essential to protecting, preserving and even marketing goods and brands in markets ranging from food and beverage to household products to agriculture to pharmaceuticals. But if you’re not familiar with the packaging industry, it will probably surprise you to learn that there are many pieces of equipment that help it bring it life. There are the likes of extrusion machines, which work to create film and other materials that are used to create packages. Next comes the pouch-, bag- and paper converting machines that turn the materials into functional packages. Printing and lamination likely also occur throughout the formation of the package, and eventually the finished package will go on to be filled and sealed. Following this step, they may also be wrapped.

Packaging wrappers are typically end-of-line machinery components that are either designed to group products to aid retailers in shelf organization and replenishment (think: bottled water) or to seal the product with a wrapping altogether (think: fresh meat on a tray wrapped in film). They may also be used to wrap pallets and cartons to make packaged goods easier for shipment. In many ways, these packaging wrappers are somewhat of an unsung hero in the packaging industry in that they provide an essential, yet very taken-for-granted function. While most packaging wrappers work with film or shrink wrap, other materials may include foils and paper, though these aren’t as widely used as film.

But while packaging wrappers may sound simple, they are available in a bevy of different styles and varieties. As we noted above, some wrappers are designed to shrink wrap pallets or cartons, while others are designed to group products together to make it easier for stores to stock and re-stock on shelves. With all that being said, this post is designed to take a closer look at the different types of packaging wrappers that are commonly utilized in the industry.

The Various Types of Packaging Wrappers

There are four main types of packaging wrappers that are utilized in the packaging industry. More information on each type is as follows.

  • Flow Wrappers: Flow wrappers are generally high-speed, work with smaller sized packages and products and normally perform more functions than just wrapping and sealing a product. In addition to the wrapping and sealing of a product, flow wrappers also often perform form and fill functions too. While flow wrappers are a general type of wrapper, there are many sub categories of flow wrappers to meet the needs of any packaging facility. Some flow wrappers are more designed for entry level companies that want to speed production, where others are much more specialized. High-speed flow wrappers are also available, and these machines are ideal for larger companies that have stricter timelines to meet. The likes of candy bars, ice cream bars, cookies, muffins and smaller medical devices and industrial goods are all ideal candidates for flow wrappers. Flow wrappers generally come in horizontal and vertical configurations.
  • Over Wrappers: Over wrappers are primarily used to seal fresh food as a means of reducing potential contamination and ensuring long-term freshness. Noting this, over wrappers are typically used with meats, poultry and other foods that are packaged in trays. These over wrappers work with film, stretching it over the tray and then heat sealing it to the bottom of the package to lock in freshness. Aside from locking in freshness and extending the product’s shelf-life, many consumers like the fact that packages wrapped this way enable them to actually see the product they’ll be purchasing or are considering purchasing. Most over wrappers are small enough to fit onto table tops, although floor models are available as well.
  • Shrink Wrappers: Shrink wrap machines work with shrink film. They work by stretching this shrink film over the product – or pallets of products – in question, then apply heat so that the film essentially “shrinks” over whatever it is covering so that it fits tightly to the product. Shrink wrap may be applied to small quantities of product (i.e. to package water bottles or soda together) or it may be used to wrap entire pallets of goods in an effort to keep items together and better protected during transportation. It may also be used to over wrap cartons and boxes. Because of the many different purposes of shrink wrap, shrink wrappers come in various different sizes. Some are small enough to nicely fit into a small, focused space on a factory floor, while others may take up a significantly larger area.
  • Stretch Wrappers: Stretch wrappers are essentially a machine of a larger scale that works with shrink film to wrap pallets and other large objects. As we noted above, one application of shrink film is wrapping the likes of pallets, boxes and cartons to make sure they stand up better to any of the rigors of transportation. That’s the role that stretch wrappers essentially play. For this reason, stretch wrappers are also commonly referred to as “pallet wrappers.” Stretch wrappers come in various configurations. For instance, some employ the use of turntables, while others use straddles, while some move pallets through a ringer to be wrapped. Due to the size of the loads that are serviced by stretch wrappers, these are one of – if not the most expensive – type of wrapper.

 

Though stretch wrappers often have the reputation as being the most expensive of all types of wrappers due to the sizes of product that they service, make no mistake about it when it comes to packaging wrappers – it’s a capital investment. But it’s an important one, as these machines are crucial to the end-of-line packaging procedures. Buy these machines brand new and it could cost tens of thousands of dollars, a price point which can be challenging for either a startup packaging company or a company who didn’t budget for a new purchase on this type of equipment. While buying a brand new wrapper is a viable option, another option is buying a wrapper that’s been previously owned and used. Service providers like Bid on Equipment have a range of previously used wrappers available for a fraction of the price of a new one that work just as well, a big benefit to those packaging companies that don’t have the money to spend on something brand new. By utilizing a credible site like Bid on Equipment, it’s like you’re getting something brand new, but at a used price.

For more information on packaging wrappers, and to browse Bid on Equipment’s inventory of wrappers, visit the company website or contact it today.