TEA DRYERS

INTRODUCTION

 

IMPROVED SUPER QUALITY TEA DRYER, This modified Dryer is a noteworthy contribution by BRITANNIA who can claim a creditable record of progress in manufacturing a comprehensive range of tea processing machinery. When designing the IMPROVED SUPER QUALITY TEA DRYER, we kept in mind the question of simplicity, as it appeared to us that in some types of dryers many features had been added to complicate the machines and increase their cost, whilst adding tittle to efficiency and are confident that we have, in a very simple form, embodied all the desirable features introduced in recent years. One of the main features of the ‘IMPROVED SUPER QUALITY1 is the LOW AIR VELOCITY, the necessity of this becoming apparent with the multiple green leaf shifting method of manufacture. The total volume thus passing through the machine has been increase thereby increasing the capacity of the machine and providing an ample margin to deal with rush crops and adverse conditions, The machine has a built in high evaporative capacity per unit of heat input. With simplified control the average output of tea in the IMPROVED SUPER QUAITY is 126-136 kg/hr. for 4′ Tea Dryer, 192-200 kg./hr for 6’ Tea Dryer & 300 kg/hr for Jumbo Tea Dryer CTC/ORTHODOX teas in single firing under normal withering condition.

 

SALIENTS FEATURES

 

  • Low Air Velocity • Increased volume of air passing through machine • Close fitting trays with fine perforations • Drying chamber

Fabricated of best quality M.S. Plate as per I.S. specification • Efficient air sealing devices • Complete accessibility to drying chamber • Smoke tight doors fitted to stove • Seven years of experience stand behind this dryer • The “Super Quality” hoids all tea dryer records • Increased output lower fuel consumption • High evaporation per kg. of tea.

 

TECHNICAL FEATURES

 

FEEDER

 

In the Super Quality Tea Dryer the feeder is fitted with blanks trays. Feeder trays are screened from hot air passing through the machine, thereby keeping the trays cool. The slope of the feeder is so deisgned that there is go possibility of any tea slipping back.

 

REVOLVING SPREADER

 

The revolving spreader fitted to the feeder is interlinked with an auxiliary revolving spreader above the top row of trays in the drying chamber, so that any adjustment in thickness of spread is automatically transmitted to the auxilliary spreader.

 

DRYING CHAMBER

 

The drying chamber is constructed entirely of the best quality M.S. plate as per I.S. Specification, having durability, strength and long life. The chamber is fully insulated to prevent heat loss and has large glass windows which allow a clear view of the inside.

An important point in the design of the ‘SUPER QUALITY’ Dryer is that the floor of the drying chamber slopes upwards, which ensures a very even air distribution throughout the machine.

TRAYS

The trays are of our latest improved pattern manufactured to very close limits and designed to allow very thin spreading having standard 1/16″ (1.587 mm.) perforations for the bottom two rows of trays and 3/32″ (2.381 mm ) for the upper rows. The use of 1/16″ (1.587 mm.) perforations in the bottom two rows, together with the dose fitting trays, effectively reduces the “fall through” to an almost negligible quanitty.

 

BEARINGS

 

The Super Quality Drying chamber has been provided with standard deep groove ball bearings to enable the shafts to carry relatively heavier thrust loads. The earlier cumbersome graphite / bronze bushes have been eliminated.

 

 

CHAIN

 

In order to ensure a much longer life, super quentity high tensile chains have been used for driving the trays. The pitch is made to accurate limits and the pins have been increased in diameter, with the object of ensuring closeness of the fit of the trays. The chain sprockets are hexagonal, and are manufactured to great accuracy to ensure satisfactory’funning of the chains.

 

EXHAUST DUCT

 

The Exhaust Duct fitted on this dryer has been made sufficiently large to prevented with glass windws on each side to allow an easy inspection of the top row of trays.

VARIABLE SPEED DRIVE

 

In Super Quality Dryer the step chain pulley has been lace with variable frequency device and is provided on the main drive so that the machine can be adjusted to any required speed. Fig. 1

GEAR BOX

 

A highly efficient and precision built speed reducer in an oil bath is placed in between the main drive and chain driving shaft. It is completely trouble free and needs no special attention except the replenishment of lubricating oil
periodically.

SAFETY CLUTCH

 

 

 

A safety device comprising a slip clutch is mounted on the main driving shaft on the chamber. This is very sensitive and if properly set according to instructions should effectively prevent any damage in the unlikely event of a jam. An additional safety measure is provided through the sheer pin device.

 

AIR SEALING DEVICES

 

These consist of adjustable baffles, the lower edges of which are provided with light hinged flaps. These should be set to just touch the leaf, and will be found very effective in preventing air leakage at the back and the front ends of the dryer, and in leveling out any slight irregularities which may arise when the leaf drops from ohe row of trays’ to the next.

 

FAN

 

The fan is of ample size to provide the maximum air volume required under the most adverse conditions. The pulleys can be fitted on either side of the fan, and the belt forks can be fitted on either side of the pulleys.

 

INSTRUMENTS

 

The Super Quality Tea Dryer is equiped with an (a) inlet thermometer (b) an Exhaust Thermometer and (c) a tow-pen recording thermograph.

 

The Mountings and Dials are particularly large, robust and legible.

 

 

SCRAPER GEAR

A scraper gear is fitted to the bottom of the drying chamber to deliver any “fall through” of very fine tea into the main discharge. The fine tea can be discharged separately through a side discharge valve, which can be fitted if so desired.

 

EASY ACCESSIBILITY

Special attention has been paid while designing this machine. All the side doors of the drying chambers can be made to open and turn on their hinges and large doors are provided both at the back and front ends of the machine for easy accessibility in cleaning and examination of the dryer.

 

STOVE

 

This is of a staggered tube design. It has the additional heating surface we introduced a few years ago. The thermal efficiency when fitted with the Economister Tubes and Anti-radiation Casting is well over 85%. The stove cleaning doors have been re¬ designed. There are mow four pressed steel doors on each side of the stove (each with a single central fastening), which can be opened, in a few seconds for cleaning purposes. A smoke tight joint is provided. We recommend the adoption of the Economiser Tubes and Anti-radiation Casing, which contribute considerably to the remarkable., stove efficiency.

 

POWER AND OUTPUT

 

It will be appreciated that the Power required is mainly that necessary for driving the fan, as the power required for the trays is less than 2 H.P. The Super Quality Tea Dryer is so designed that it depends largely on the moisture content of the fermented leaf fed into the machine and the permissible drying temperature.