Boiler Blog | Nationwide Boiler Inc.

When we think about boilers, there are a two types that typically come to mind; firetube, or scotch marine, and watertube boilers. These types of boilers can be classified as hot water, steam, high pressure, and low pressure. In today’s blog post we will be answering the question: what are the basic differences between the different types of boilers?

Although their final function is the same, the main difference between a firetube and watertube boiler is the construction and design of each system. In a firetube boiler, water inside a vessel is surrounded by tubes that contain combustion gases. In other words, the ‘fire’ is inside the tubes, making it a ‘firetube’. Watertube boilers are essentially the opposite in design. Combustion gases surround a series of tubes that contain water, coining the name, watertube.

By definition, high pressure boilers are built to a maximum allowable working pressure (MAWP) above 15 psig, while low pressure boilers are designed for operation at 15 psig or below. Low pressure boilers are most commonly utilized in heating applications and require less maintenance than that of a high pressure unit. Furthermore, firetube boilers can be built for both low and high pressure applications, while watertube boilers are typically built for high pressure needs.

Some may think that firetube and watertube boilers are in the same category as hot water and steam boilers. However, steam and hot water boilers are actually a classification, and can be considered a subcategory to firetube & watertube boilers.

Hot water and steam boilers operate in a very similar manner, but hot water boilers don’t actually produce steam. In reality, a hot water boiler is just a fuel fired hot water heater, in which heat is added to increase the temperature to a level below the boiling point. Hot water boilers are not as powerful as steam boilers, which is why they are more commonly used in heating applications providing hot water at 120 – 220F.

Steam boilers heat water to levels that are above boiling point, in order to produce steam. They are much more powerful and are utilized in more industrial and heavy-commercial applications. Steam boilers can be designed to produce either saturated or superheated steam, which we will discuss further on in a future post.  

Playing off our last topic, some might argue that there is another boiler type, or classification, to consider. In today’s article, we will discuss the difference between saturated and superheated steam boilers, and the applications that they are most commonly used for.

Let’s begin by talking about the science behind these two types of steam. Simply put, when water is heated to its boiling point, it will begin to vaporize and saturated steam is produced. Superheated steam occurs when the water is continually heated to temperatures beyond the boiling point, without any increase in pressure. Also known as dry steam, superheated steam has a much lower density and produces zero condensate.

As with the other types of boilers previously discussed, saturated and superheated steam boilers each have their own unique advantages and disadvantages and are better geared for certain applications over others. Saturated steam has a high density and is an excellent heating source. Commonly utilized in food processing, sterilization, district heating, and pulp & paper processing, saturated steam has the following advantages: 

• Produces fast and even heating due to latent heat transfer
• The temperature can quickly be established through the control of pressure
• Has a high heat transfer coefficient, which requires a smaller heat transfer surface and in turn, allows for reduced initial
• equipment costs

Superheated steam is not typically utilized in heat transfer applications. However, due to its dry composition and ability to cool while remaining in the same physical state, it can be extremely versatile and is most commonly utilized in refineries, for generating electricity, and for powering turbines.

Superheated steam is ideal for powering turbines for the following reasons:

• The dry steam allows for steam-driven equipment to function effectively and efficiently (while condensate from wet steamwould negatively affect performance of the equipment)
• Improves thermal efficiency and work capabilities of turbines
• Contains zero condensate, minimizing the risk of corrosion and erosion damage

With a low heat transfer coefficient that is equivalent to that of air, superheated steam has more energy and can work harder than saturated steam, but the heat content is less useful. In addition, boilers that are built to produce superheated steam require more expensive components on the boiler system, in comparison to a saturated steam boiler. Therefore, it is extremely important to do your homework ahead of time to determine which type of steam is best suited for your particular application.

Did you know that Nationwide Boiler maintains a fleet of both saturated and superheated steam boilers for rent and for sale? In fact, we own the World’s Largest 125,000 lb/hr saturated steam mobile boiler, and the World’s Largest 110,000 lb/hr superheated steam mobile boiler!  Visit our website at nationwideboiler.com to learn more.

Located in Lathrop, CA, the Discovery ChalleNGe Academy is a Community High School run by the California National Guard in partnership with the San Joaquin County Office of Education. Part of the National Guard Youth ChalleNGe Program (NGYCP), the Academy was founded in 1993 to assist students in enhancing life skills, education levels, and employment potential.  This military-style program houses, feeds, and educates 16 to 18-year-old young adults that were unable to complete high school due to varying unfortunate circumstances. The program allows students to earn 65 High School credits while developing leadership, job, and academic skills, while improving self-esteem, pride, and confidence.  

With the school year coming to an end and graduation quickly approaching, The Academy set up a trip for a group of students working to complete their high school credits, and Nationwide Boiler was honored to participate. The goal of this field trip was to educate the graduating class on the many different education, trade, and career opportunities available to them once they step out into the real world.

The first stop of the day was San Jose State University, where they toured the campus and the new $130M recreation center. After experiencing lunch like a college student in the Student Union, they headed north to Nationwide’s shop in Fremont. Upon arrival, the students congregated on the patio to hear a warm welcome from President & CEO, Larry Day, and Vice President, Michele Tomas. The group was then taken on a tour of our 26,000 sq. ft. shop, where day-to-day activities include; boiler maintenance, welding, painting, electrical work, fabrication, equipment assembling, and other technical skills.

Nationwide Boiler’s Shop & Service Managers, Andrew Horne and Michael Rosmando, educated the students on the basics of a boiler system, and walked them through the different trade skills and career opportunities available not just here at Nationwide, but from other companies in similar and varying industries. Many of the students were interested in welding, electrical, and accounting careers. Who knows… we may have just met future Nationwide employees!

At Nationwide Boiler, we feel strongly about training and educating our youth so that we are able to successfully sustain our business and industry for future generations, and we are happy to have had the opportunity to be a part of this inspiring program. Thank you to Todd Robinson and the NGYCP for providing young adults with an opportunity that will help them secure their futures.

Recent studies show that companies are restructuring their culture, steering away from the competitive work environment with minimal employee recognition, and shifting towards adapting a more team-centric and collaborative working atmosphere.

Nationwide Boiler is proud to say that we have always been a company that encourages team building, and are more than happy to recognize and reward our employees as they excel in their position. In fact, in addition to 5-year length of service awards that are presented at our annual Christmas party, we recognize employees who make a big impact with our ‘Big Kahuna’ award at each quarterly birthday celebration.

To encourage camaraderie throughout our company, Nationwide Boiler coordinates multiple events for employees to take part in. This year we have a total of 6 sporting events in the lineup, including soccer, baseball, and college football. The next game we are looking forward to is the Oakland A’s vs. Texas Rangers, and of course, we will be rooting for the A’s! We also coordinate multiple barbeques & dessert socials throughout the year to satisfy our many food lovers and celebrate certain events. Most recently, we held our Independence Day barbeque the week of July 4^th. We had grill masters, Larry Day and Michele Tomas, cook up some delicious burgers and hotdogs; while Holly Lepo spoiled us all with her famous and delicious chili, yum! We can’t wait for the next one.

In addition to being sports enthusiasts and foodies, we also like participating and getting in on the action. We recently hosted a bowling lunch at our local bowling alley, Cloverleaf Family Bowl. The group was split into 8 teams (with fun, creative team names), in a competition to win the title of Nationwide Boiler’s 2019 Bowling Champions. In the end, Team Vapor & Team Combustion went head to head, but Team Vapor came out on top. Congratulations to Tim McBride, Phil Blake, Nic Petty, and Sandy Nevels. Let’s see who will take home the title at our next bowling event!