The Republic of Tea, Nashville, Illinois, is a privately owned gourmet tea company and a leading purveyor of specialty teas throughout the United States. For its customers to get a high quality tea, the Republic goes to India, China and South Africa to buy "full leaf" teas as opposed to lower quality "dust" cuts used in cheaper teas.
The company was established in 1992 and has 70 employees. During its growth period, Republic of Tea had to upscale its manufacturing process to meet a growing demand for tea.
Attempt to Eliminate Metal Contamination
To eliminate fine metal contaminants, the company tried a variety of preventative measures. Initially, tea was passed through several different sized screens to remove any foreign matter from loose leaves and fanning blends (tea bag blends). This method worked well for the tea bag blends, but posed a big problem for the high quality full leaf teas. When passing leaf teas through screens, the delicate tea leaves would break up; thereby, lowering the quality of the loose leaf teas.
Another problem encountered was the screens would separate the full leaf and herbal blends causing the tea blends to funnel and not flow through the hoppers; thus, creating problems for the filler operation by slowing production and lowering the quality of the teas.
Eriez Magnetics Finds a Solution
After analyzing the situation, Eriez Magnetics, Erie, Pennsylvania, manufacturer of a broad line of magnetic products, recommended Erium™ powered permanent grate magnets be inserted in the hopper of the tea packing machines to remove any foreign metal matter that may contaminate the product during the blending and packing process.
Each of the tea bag machines is equipped with two round 18 grate magnets. One magnet is placed in the bottom of the transfer hopper and the second grate magnet is placed in the bottom of the hopper at the last entry before tea is filled into tins or tea bags. This is the final opportunity in the operation to remove foreign matter from the finished product. The leaf machine is equipped with one round 18 grate magnet placed at the bottom of the hopper located just before the filler.
According to George Phillips, minister of plant operations, "As the Republic of Tea grows, we will continue to use Eriez magnets as an important part of our quality control program to ensure customer satisfaction that is good to the last sip."
How the Grate Magnet Works
Powered by Erium permanent magnet compound, the grate magnet is constructed with a flexible basic design that makes it a protective magnet for virtually any shape hopper. In operation, the sturdy grid bars positioned over the magnetic element act as baffles to deflect the flow of material onto the magnetic tubes where iron contamination is trapped and held. The built-in baffles control excessive speeds of material, but a smooth steady flow is not obstructed.
The grate magnet consists of a series of parallel magnetic tubes, each consisting of non-magnetic stainless steel tubing encapsulating a powerful magnetic circuit. The tubes are spaced and held in position by non-magnetic stainless steel tie bars. Parallel with the magnetic portion and centered between them are stainless steel deflectors that serve a two-fold purpose. They act as a material baffle to prevent excessive speeds and they direct all of the material onto the face of the powerful magnets.
Installation is effected by simply placing the magnetic grate in the hopper, the ends of the magnetic tubes resting against the sides. In cases where the ends of the hopper are unusually steep, small strips may be attached to give the grate adequate support.
Maintenance of these powerful non-electric permanent magnetic units involves nothing more than periodically lifting the unit out of the hopper and wiping it clean of ferrous contaminants.
The magnets are available in rectangular, oval and round designs to fit any size or shape of hopper. Sturdy grid bars deflect material flow to the magnetic tubes where iron contamination is trapped and held.