PAES 248:2010 - 249:2010 Flashcards
PAES 248:2010
Agricultural Machinery – Fruit Dryer – Specifications
air moving device that is used to force heated air through the mass of materials to be dried at
the desired air flow rate and pressure
fan
blower
ripened ovary or ovaries of a seed-bearing plant that are edible, usually sweet and in fleshy
form
fruit
device for removing excess moisture from the fruits, generally by forced or natural
convection with or without addition of heat
fruit dryer
difference between the maximum and the minimum moisture content randomly sampled after
drying
moisture gradient
chamber wherein air pressure is developed for uniform distribution of the heated air through
the material to be dried.
plenum
any device that is used to avoid human accident and/or damage to the parts and components
of the dryer during the operation and automatically shuts-off the operation of the dryer in
case of malfunction
safety device
ratio of vapor pressure of water in the product to the water vapor pressure of pure water at the
same temperature.
Note: Measure of water available for the growth of microorganism
water activity
Classification
System Operation
Heating System
Classification ( System Operation)
Batch/Tunnel type
Tray/Cabinet type
Mechanical dryer wherein the sliced fruits in fixed volume are held in the drying chamber in
batches until it reaches the desired moisture content.
Batch/Tunnel type
Mechanical dryer wherein fixed volume of sliced fruits are placed on perforated tray(s) in the
drying chamber until it reaches the desired moisture content.
Tray/Cabinet type
Classification (Heating System)
A. Method of heating the drying air
1. Fuel burning
- direct
- indirect
2. Heat pump
B. Fuel source
- conventional energy
- non-conventional energy
- biomass energy
- solar energy
This type of fruit dryer heats up the drying air by direct burning of fuel inside the heating
chamber.
Fuel burning
Dryer in which the products of combustion come into direct contact with the product being
dried.
Direct
Dryer in which the products of combustion do not come in contact with the products being
dried. This type uses heat exchanger.
Indirect
Fruit dryer type that heats the drying air through the use of reversed refrigeration system.
Heat pump
Source of energy which includes petroleum-based fuels (LPG and propylene).
Conventional energy
Source of energy that includes non-petroleum fuels such as biomass and solar energy.
Non-conventional energy
Fruit dryer is coupled to an indirect-fired biomass furnace where the drying air is being
heated using heat exchangers.
Biomass energy
Fruit dryer is coupled to an air type solar collector where the air is being heated and ducted to
the drying chamber. Air circulation can be by natural convection or by using blowers.
Solar energy
Maximum range of drying air temperature to be used in heat pump fruit dryer shall
be ???
60°C to 70°C.
Air velocity inside the drying chamber of fruit dryer should be at least ???.
0.2 m/s
Bolts and screws to be used shall conform to ???
PAES 311 and 313.
Final moisture content wet basis of the fruit to be dried shall not be more than ???
15%.
Water activity of dried fruits shall not be more than ???
0.70 at 25 °C.
When drying sliced mango, appearance/color shall be moderate yellowish brown and hardness shall be in between ???
4.4g to 6.4g
Minimum drying efficiency of the fruit dryer shall be ???
75%.
Actual performance factor shall be at least ??? of the total carnot cycle performance
factor of the heat pump fruit dryer system.
70%
The noise emitted by the dryer shall not exceed ???
92 dB(A).
Welded joints shall not be less than ??? side fillet welded. Undercut shall
not exceed ??? for any length of weld.
4 mm (1/8 inch)
2 mm (1/16 inch)
Warranty against defective materials and workmanship shall be provided for parts and
services except for normal wear and tear of consumable parts such as belts within ??? from the date of purchase of the fruit dryer.
one year
The construction shall be rigid and durable without breakdown of its major components for at least ??? from the date of purchase of end-user.
one year
The outer frame of the heat pump fruit dryer shall be covered with a minimum of
??? thick styrofoam as insulation.
one-inch
volume of air in cubic meters delivered to the mass of fruits per minute
airflow rate
mean temperature of the air to be used for drying the fruit, measured at a number of points as
close as practicable to its entry to the drying bed
drying air temperature
maximum capacity that the fruit dryer can removed moisture content per unit time
drying capacity
ratio of the total heat utilized to vaporize moisture in the material, to the amount of heat
added to the drying air, expressed in percent
drying efficiency
heat utilization efficiency
amount of water removed per unit of time, expressed in kilogram per hour
drying rate
ratio of the total heat utilized for drying, to the heat available in the fuel expressed in percent
drying system efficiency
total amount of fuel consumed divided by the total drying time
fuel consumption
total amount of heat utilized to vaporize moisture in the material, expressed in kJ/kg of water
heat utilization
weight of fruits required to fill the dryer at the initial moisture content
holding capacity
load capacity
ratio of the average percent moisture content removed from the fruits, to drying time,
expressed in percent per hour
moisture reduction rate
pressure build-up in the plenum chamber to maintain uniform dustribution of air flow through
the sliced fruits, expressed in mmH2O
static pressure
The fruit to be used shall be single variety and the minimum moisture content shall be ???
The fruits shall be peeled and sliced before drying.
75%.
Thermometer shall be mounted on or inside the dryer for temperature sensing. These shall be
mounted at the following locations:
(1) near the dryer to sense ambient temperature;
(2) at the
plenum interface;
(3) after the plenum; and
(4) immediately outside the dryer to sense exhaust
air temperature.
Samples for moisture content determination shall be taken at the ???
drying racks (for vertically arranged trays) or ??? drying trays (for horizontally arranged trays) of the fruit dryer.
bottom, middle and top
beginning, center and last
shall be taken at the plenum/transition duct (between blower and the dryer).
Static pressure
This shall be taken using oven-dry method.
Moisture content
Weigh ??? of sliced fruit samples, place in the moisture can and record the weight.
100g
Dry the sample in the oven with temperature of ???
103 °C ± 1 °C for 24 hours.
Air velocity
Measurement of air velocity shall be made at the ???.
air duct
Temperature
??? temperature shall be recorded.
Fruits temperature, drying air temperature, ambient and exhaust air wet bulb and dry bulb
This shall be taken at the plenum/transition duct (between blower and the dryer).
Static pressure
Sound level
This shall be measured with the dryer full of fruits, operating at recommended settings of
different components, with burner on. (The station of the operator will be considered to be
within ??? of the controls).
one meter
