Screw Jacks and Food Processing
It's time for the annual 4th of July barbecue season. As we all prepare for the upcoming weekend festivities, I also can't help thinking about ActionJac™ screws jacks and the many uses they have in the food industry. Screw jacks have definitely served their purpose in the industrial sector over the years with many different types of factory applications. The same goes for the transportation segment in manufacturing, service, and ultimately the vehicles themselves.
There have been some interesting linear motion technical innovations designed to serve the food segment in recent years. But, many of the emerging food applications are still perfect for the venerable screw jack. It's simple yet effective design is timeless and it is a true work horse for food applications.
In the food sector, screw jack systems are typically deployed in three common and versatile arrangements. Let's talk about a few of these in more detail.
"U" Arrangements
“U” arrangements are often times the preferred screw jack system configuration for manufacturers in the food equipment industry.
Application Example - Controlling oven heating element
A leading baked goods manufacturer is developing a new product line that must be pass closer to the top heating element of the conveyor oven. Previously, the top heating element of the oven was fixed and could not move. The new product must be positioned up to 14 inches closer (and be fully adjustable to accommodate the other product versions).
Key Requirements
- The top heating element weighs 5,000 pounds.
- The manufacturer anticipates only adjusting the height once or twice a month.
- The actuators and power source must be located outside of the oven frame.
- Travel rate is negligible if the total travel can be reached in less than 60 seconds.
Screw Jack Solution
- A 10-ton jack was selected for the mounting condition to fulfill the safety requirements of the application.
- This application’s infrequent cycles make an ACME screw jack the best fit.
- U arrangement included a single 5-Horsepower 1750 AC Motor that allows full travel in 36 seconds, food-grade grease, compression load and a double safety factor.
- Upright rotating jacks allowed the jacks to be easily retrofitted to the existing oven with minimal modifications.
- The jacks can be fully loaded in both the retracted and extended positions.
“T” Arrangements
“T” arrangements are another useful screw jack system option for food equipment manufacturers.
Application Example - Positioning large mixer
A manufacturer needs to periodically raise and lower a large cylindrical mixer 8 inches during the mixing cycle to facilitate product testing.
Key Requirements
- The 1,700-pound cylinder is mounted on a movable cart, allowing for the final product to be re-positioned to a separate dispensing station.
- The jacks will be loaded in tension; therefore column strength will not need to be considered.
Screw Jack Solution
- The T arrangement offers a repeatability and reliability that gives the manufacturer assurance their production will not be compromised by ensuring the load is lifted uniformly and safely.
- For this configuration, a ball screw jack is used to minimize the size of the motor drive.
- Based on the mounting frame, the inverted rotating configurations will be used. Specifications for the arrangement include: a single 1750 AC Motor and 2.5HL-BSJ with a 12–to-one gear ratio and the capability to travel 8 inches in five seconds.
“H” Arrangements
“H” arrangements are one of the most common configurations used for worm gear screw jacks.
Application Example - Controlling a material lift
A food equipment manufacturer of steel frames for the commercial dairy industry is building a material lift which contains a stack of prefabricated frames. The material lift will index up as each frame is removed by an automated grip from the top of the stack.
Key Requirements
- The jack will index up 1 inch in 2 seconds every 30 seconds (compression load travels 6 inches).
- After the last frame is removed, the jacks will fully retract to the collapsed position in 6 seconds waiting for the next load of frames.
- Complete cycle time is 10 minutes running 6 hours per day, 5 days a week.
- When fully loaded, the frames hold a total weight of 16,800 pounds, but when the load is fully extended, the weight is less than 5,000 pounds.
- The design calls for a four-jack arrangement lifting from underneath the lifting stage, driven by a single motor.
- The desired design life for the arrangement is one year, as the application is expected to go through 3,120 cycles a year.
Screw Jack Solution
The frequency of these cycles and suggested design life makes the use of a ball screw jack the best option for this application. Using upright translating jacks allows the jack system to be located under the material lift without creating an obstruction.
Stainless Steel Jack Options
There is an ever-increasing list of opportunities to utilize stainless steel jacks in the food segment. Stainless steel jacks are ideal for use in demanding environments where corrosion resistance is required. All the external components for these jacks are manufactured are manufactured from 300 series Stainless Steel materials and capacities range from 1,300 to 23,000 pounds.
