Tag Archives: maintenance

A view from under the elevator car of an in-ground jack.

All About Elevator Jacks

A view from under the elevator car of an in-ground jack.
A view from under the elevator car of an in-ground jack with the piston extended.

When it comes to many elevator applications, especially for buildings between 2 and 5 stories, you will find a hydraulic jack is a common, yet crucial part of the system that drives the elevator up. As a matter of fact, approximately 70% of all elevators installed are hydraulic in nature and contain jacks.  The jacks are part of a system that includes hydraulic fluid, tanks, motors, and pumps with the jack being the final piece of the system.  So, understanding the basics of the elevator jack is crucial if you are considering buying a new elevator or modernizing the jacks in an existing elevator.

Depending on the system you have, the distance your elevator travels, and the space available, you have several options available. This article will explain the various types of jacks and the advantages and disadvantages associated with each.

  • Single Stage Holeless – Many times when new elevators are being placed, you can’t drill a hole in the bottom of the elevator pit or it is cost prohibitive to do so. Enter the holeless elevator jack. The most common jack used for short travel distances is the single-stage variety. A single stage means that it is one piston that goes up and down and it does not telescope when it reaches a certain height. These can be used for passenger or freight elevators.

The benefits of this type of jack (often called a twin-jack and used in tandem on either side of the elevator car) is that they are lighter and easier to put into place, are the most economical choice, and can be designed to carry very heavy loads. On the downside, because you are often dealing with two jacks, more adjustments must be made and it takes a bit more maintenance. Also, because the jacks commonly go on either side of the car, and there is no hole for the jacks to retreat in, there must be more space at the top of the hoistway above the car.

  • Single Stage In-Ground – This option is very common, especially when you can drill a hole in the bottom of the pit and want to travel multiple floors.  Because it does not telescope, the moving parts are limited and it is, therefore, reliable. It has also been around for a very long time as a solution and has a solid track record.

The good things about a single stage in-ground jack is that it is easy to install, fairly economical, especially for mid-rise projects, has a huge capacity, and maintenance is limited to one jack.   They also provide a very smooth ride. On the downside, the jack is in a hole. This can lead to leaks of hydraulic fluid into the underground water supply or contamination of the soil. Keep in mind that most of the contamination issues have been resolved with new technology and regulations. However, the threat remains: units can have a cracked PVC casing which can cause flooding of the pit and some fluid leakage. Also, old corroded sheaths that the jacks reside in need to be replaced, usually at a significant cost.   Also, the depth of the jack must be equal to the travel of the elevator car. This can mean an expensive, deep hole.

  • Telescopic Jacks (Holeless and In-Ground) – Telescopic jacks can have up to four pistons, each traveling inside each other. These are used when a more compact solution is needed for either freight or passenger elevators. Telescopic jacks going in-ground will reduce the depth of the hole required, but can sometimes be more costly in and of themselves.

The big plus is that there is a reduced drilling cost for an in-ground application and a higher travel distance than for holeless projects.  Also, the installation is usually fast as the jacks are compact and easy to handle. The disadvantages include the obvious; there are more moving parts, so initial set up may be more complicated (bleeding the jack completely, is required). Depending on overall travel distance, follower guides will be needed, requiring additional engineering. Long-term maintenance may be more costly, as well. Finally, there are simply more packing and seals due to multiple pistons.

Jack Travel-01

Each of the above jacks have their place and purpose depending on travel distance, but, as you can see in the chart, there is overlap based solely the height the elevator needs to go to. Other factors include price, the ability to drill, and even personal preference (some feel the ride is better in elevators that have an in-ground jack).

The best way to determine the optimal option for your building project is to contact an elevator consultant or an unbiased company that can provide any type of elevator.  They should welcome all your questions and be willing to break down all possibilities by price or other factors important to your project. If you would like to talk with us about elevator jacks, visit us here.

Advertisements

Safety: A Primary Concern of Modular

This traction elevator is one we toured at Elevator University.
Safety equipment is a must.

If you work in construction at all, you’re probably familiar with the the term “workplace falls”. Two past headlines concerning workplace falls involving elevator shafts include: “Worker Critical After Fall Down Elevator Shaft” and “Man Recuperates After Surviving Fall Down Elevator Shaft.” In the first example, the scaffolding the man was working on collapsed. He fell down the shaft and suffered two broken legs and a broken pelvis. He is expected to make a full recovery.

The second man didn’t fare as well. He was finishing concrete near an elevator opening when he lost his balance and fell 45 feet, breaking two vertebrae and ribs. Fortunately, he still has feeling in his legs and plans to walk again in the future. A third recent accident is under investigation, but it seems that it was an accidental fall down a hoistway as well, this time resulting in death.

Click for ways to be safe!

Elevator U Report: Maintenance – It’s Just Business

Recently, I sat in on a great discussion at Elevator U regarding elevator maintenance. Elevator U is an organization that has an annual gathering of elevator pe

Elevator U Final

rsonnel from colleges and universities around the country. The conference is a great opportunity to meet and greet some great folks in the elevator business and to learn a lot of valuable information through taking part in the various seminars and breakout sessions about the industry. One of the speakers this year was Dr. Clemense Ehoff, an accounting professor at Central Washington University. He is a published writer on information specific to the elevator industry, especially elevator maintenance.

During his presentation, Ehoff made a couple of important points about the vertical transportation industry that ought to be paid special attention by those that own buildings with elevators…Click for the whole report.

Elevator U: The Myth of Maintenance Teamwork

pierre-etienne-vachon-116891 (1)
Photo by Pierre-Etienne Vachon on Unsplash

Long-term planning for elevator maintenance takes cooperation from several parties and often is equated to teamwork. However, the idea that a team is always the solution to the problem often misses the bigger point. At the recent Elevator U conference we learned a lot about the various people that make elevator maintenance systems work but, surprisingly, the word team was never mentioned.

This is may be because when you hear the word “team,” you think of a group of individuals all dressed in the same uniform striving for victory, all pulling in the same direction. Even though everyone’s in-game goals may be different, victory for the team is always the objective, so they cast self-wants aside for the win.

Baseball is a great example of this.  See how elevators equates to baseball by clicking here.

Benefits of the MRL Elevator

fixed-mrl-motorIn 1996, Kone introduced the world to its first Machine Room-Less traction elevator (MRL), and worldwide, this design has become common for medium-sized buildings. While regulations, code requirements and new product hesitancy have made growth slower in the United States, we are now seeing steadily increasing installations.

The MRL elevator is attractive due to emerging technology that significantly reduces the size of the electric motors normally used with traction elevators. This gives elevator manufacturers the option to replace the large machine room used to accommodate the motor with a small, more efficient motor placed in the overhead at the top of the hoistway.  Instead of accessing the machine via ladders onto a roof, it is serviced from the car top.

However, just because it is becoming a common choice doesn’t mean the MRL is the right elevator configuration for your project.   Below are some of the advantages and disadvantages of MRLs to consider when looking for a new or replacement elevator.

  1. Energy savings – Some of the early claims were an energy savings of up to 80% compared to hydraulic units. However, closer examination has revealed those numbers may be inflated. This is especially true when comparing travel up and down, as hydraulic units are extremely efficient when going down. It is now thought that the running costs are reduced about half as much as previously thought, depending on use.
  2. Space saving – There is no doubt that without a traditional traction machine room, construction is simplified, as there is no need for rooftop access and the hoistway protrusion above the roof is smaller.  Architects may appreciate this flexibility.
  3. Comparable durability, ride and safety – Early concerns were the MRL would not be as safe or as durable as a standard traction elevator, or the quality of the ride might suffer. MRLs have proven to be just as safe and comfortable as standard overhead traction, though they haven’t been around long enough to prove or disprove long-term durability.
  4. No hydraulic oil used – Currently, there are some environmental concerns with oil usage and possible oil seepage or spills, especially in elevators with in-ground jacks. MRL’s can alleviate those concerns. However, many of those concerns are now overstated, as all in-ground jacks must be contained in PVC liners. Also, hydraulic oil can now be made from biomass instead of petroleum.

Some of the downsides of MRL’s to consider:

  1. Higher initial investment – They simply come with a higher price tag for low and medium rise applications.
  2. Higher standby power requirement – While in operation, they are an energy saver, but when they are inactive, they use more energy than hydraulic elevators.
  3. Higher maintenance costs – MRLs, like traction elevators in general, have more moving parts and are thus more complex to service.  Thus maintenance costs are typically higher.
  4. Higher repair costs – Due to part availability, repair time could be longer and more expensive. Also, many components must be refurbished or repaired at the manufacturer.
  5. Harder to service – The basic thought is that the elevator car top will serve as the service platform for the motor. If the elevator car cannot be moved to the top of the hoistway, getting to the motor safely may be a problem. Access to the motor needs to be considered before installation.

The takeaway is that there are several positives and negatives when it comes to making a decision about MRL’s. Depending on the project, age and condition of your current elevator, an MRL may make sense in the long run. On the other hand, in some circumstances, a hydraulic system is superior in initial investment and long-term maintenance.

It is important to gather information before you decide, and it helps to know the amount of traffic you are expecting, the total travel distance and what, if any, environmental concerns you have when thinking about a project. To get more guidance on the decision, we recommend you get an unbiased opinion from a company that offers a wide variety of elevators, including both MRL and hydraulic options or elevator consultant. The engineers and consultants at Phoenix Modular Elevator are ready and willing to discuss all of these elevator possibilities at any time.