PAES 248:2010 - 249:2010

Question 1

PAES 248:2010

Answer 1

Agricultural Machinery – Fruit Dryer – Specifications

Question 2

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

Answer 2

fan
blower

Question 3

ripened ovary or ovaries of a seed-bearing plant that are edible, usually sweet and in fleshy
form

Answer 3

fruit

Question 4

device for removing excess moisture from the fruits, generally by forced or natural
convection with or without addition of heat

Answer 4

fruit dryer

Question 5

difference between the maximum and the minimum moisture content randomly sampled after
drying

Answer 5

moisture gradient

Question 6

chamber wherein air pressure is developed for uniform distribution of the heated air through
the material to be dried.

Answer 6

plenum

Question 7

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

Answer 7

safety device

Question 8

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

Answer 8

water activity

Question 9

Classification

Answer 9

System Operation
Heating System

Question 10

Classification ( System Operation)

Answer 10

Batch/Tunnel type
Tray/Cabinet type

Question 11

Mechanical dryer wherein the sliced fruits in fixed volume are held in the drying chamber in
batches until it reaches the desired moisture content.

Answer 11

Batch/Tunnel type

Question 12

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.

Answer 12

Tray/Cabinet type

Question 13

Classification (Heating System)

Answer 13

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

Question 14

This type of fruit dryer heats up the drying air by direct burning of fuel inside the heating
chamber.

Answer 14

Fuel burning

Question 15

Dryer in which the products of combustion come into direct contact with the product being
dried.

Answer 15

Direct

Question 16

Dryer in which the products of combustion do not come in contact with the products being
dried. This type uses heat exchanger.

Answer 16

Indirect

Question 17

Fruit dryer type that heats the drying air through the use of reversed refrigeration system.

Answer 17

Heat pump

Question 18

Source of energy which includes petroleum-based fuels (LPG and propylene).

Answer 18

Conventional energy

Question 19

Source of energy that includes non-petroleum fuels such as biomass and solar energy.

Answer 19

Non-conventional energy

Question 20

Fruit dryer is coupled to an indirect-fired biomass furnace where the drying air is being
heated using heat exchangers.

Answer 20

Biomass energy

Question 21

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.

Answer 21

Solar energy

Question 22

Maximum range of drying air temperature to be used in heat pump fruit dryer shall
be ???

Answer 22

60°C to 70°C.

Question 23

Air velocity inside the drying chamber of fruit dryer should be at least ???.

Answer 23

0.2 m/s

Question 24

Bolts and screws to be used shall conform to ???

Answer 24

PAES 311 and 313.

Question 25

Final moisture content wet basis of the fruit to be dried shall not be more than ???

Answer 25

15%.

Question 26

Water activity of dried fruits shall not be more than ???

Answer 26

0.70 at 25 °C.

Question 27

When drying sliced mango, appearance/color shall be moderate yellowish brown and hardness shall be in between ???

Answer 27

4.4g to 6.4g

Question 28

Minimum drying efficiency of the fruit dryer shall be ???

Answer 28

75%.

Question 29

Actual performance factor shall be at least ??? of the total carnot cycle performance factor of the heat pump fruit dryer system.

Answer 29

70%

Question 30

The noise emitted by the dryer shall not exceed ???

Answer 30

92 dB(A).

Question 31

Welded joints shall not be less than ??? side fillet welded. Undercut shall not exceed ??? for any length of weld.

Answer 31

4 mm (1/8 inch) 2 mm (1/16 inch)

Question 32

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.

Answer 32

one year

Question 33

The construction shall be rigid and durable without breakdown of its major components for at least ??? from the date of purchase of end-user.

Answer 33

one year

Question 34

The outer frame of the heat pump fruit dryer shall be covered with a minimum of ??? thick styrofoam as insulation.

Answer 34

one-inch

Question 35

volume of air in cubic meters delivered to the mass of fruits per minute

Answer 35

airflow rate

Question 36

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

Answer 36

drying air temperature

Question 37

maximum capacity that the fruit dryer can removed moisture content per unit time

Answer 37

drying capacity

Question 38

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

Answer 38

drying efficiency heat utilization efficiency

Question 39

amount of water removed per unit of time, expressed in kilogram per hour

Answer 39

drying rate

Question 40

ratio of the total heat utilized for drying, to the heat available in the fuel expressed in percent

Answer 40

drying system efficiency

Question 41

total amount of fuel consumed divided by the total drying time

Answer 41

fuel consumption

Question 42

total amount of heat utilized to vaporize moisture in the material, expressed in kJ/kg of water

Answer 42

heat utilization

Question 43

weight of fruits required to fill the dryer at the initial moisture content

Answer 43

holding capacity load capacity

Question 44

ratio of the average percent moisture content removed from the fruits, to drying time, expressed in percent per hour

Answer 44

moisture reduction rate

Question 45

pressure build-up in the plenum chamber to maintain uniform dustribution of air flow through the sliced fruits, expressed in mmH2O

Answer 45

static pressure

Question 46

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.

Answer 46

75%.

Question 47

Thermometer shall be mounted on or inside the dryer for temperature sensing. These shall be mounted at the following locations:

Answer 47

(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.

Question 48

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.

Answer 48

bottom, middle and top beginning, center and last

Question 49

shall be taken at the plenum/transition duct (between blower and the dryer).

Answer 49

Static pressure

Question 50

This shall be taken using oven-dry method.

Answer 50

Moisture content

Question 51

Weigh ??? of sliced fruit samples, place in the moisture can and record the weight.

Answer 51

100g

Question 52

Dry the sample in the oven with temperature of ???

Answer 52

103 °C ± 1 °C for 24 hours.

Question 53

Air velocity Measurement of air velocity shall be made at the ???.

Answer 53

air duct

Question 54

Temperature ??? temperature shall be recorded.

Answer 54

Fruits temperature, drying air temperature, ambient and exhaust air wet bulb and dry bulb

Question 55

This shall be taken at the plenum/transition duct (between blower and the dryer).

Answer 55

Static pressure

Question 56

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).

Answer 56

one meter