Task 3. Give definitions to the following items:
1.displacement ventilation (e) |
a)the mechanical system or equipment used to circulate air or to replace stale air with fresh air. |
2. a hub (d) |
b) The rotating member of a turbine, blower, fan, axial or centrifugal pump, or mixing apparatus, also known as a rotor. |
3. an impeller (b) |
c) a type of ventilation applied in specific areas in mine |
4.ventilation (a) |
d) the central portion of a wheel, propeller, fan, etc., through which the axle passes |
auxiliary (local) Ventilation (c) |
e)a method of ventilation when dust or gases change their direction and flow another way. |
Task 4. Put in the missing words from the box:
A __1 fan is a device for producing a current of fresh air to ventilate a room in mines. Fans consist of a series of radial ___2 blades attached to a ___3 central rotating hub .The rotating assembly of blades and hub is known as a ____4 rotor and it may or may not be enclosed in a housing. Fans may be driven by an ____5 electric motor , an internal-combustion engine, a steam turbine, a gas turbine, or other motive power.
Hoists
1. Hoist is a device used for vertical transportation of passengers or freight___T
2. There are four types of hoists used in mining applications.__F
3. Multirope hoist is a type of double-drum one, used in extremely shallow shafts._T
4. The lifting element is both chain type and wire rope type wrapped around a drum to move a skip.___F
5. Multirope hoist can not operate if one of the drum cables is out of work.___T
Task2. Match heads and tails:
1 |
a) wrapped around a drum to move a skip |
2. The lifting element is either chain type or wire rope type (a) |
b) smaller applications for raising up and moving down the freight |
3. Friction hoists are mounted on the ground above the mine shaft, or (e) |
c) passengers or freight to different levels in a mine |
4. Hoist is an automatic device for vertical transportation of (c) |
d) electric motors, direct current drives utilizing solid-state converters (thyristors). |
Power element is started by (d) |
e) at the top of the head frame. |
.
Single-drum hoist can be used in …(b)
Task 3. Give definitions to the following items:
Drum(b) |
a) it is intended to balance the load |
Skip(d) |
b) a rotating cylindrical part in a machine |
Counterweight(a) |
c) an apparatus for lifting heavy or cumbersome objects. |
Cable(e) |
d) a cage or bucket in which men or materials are lowered and raised in mines and quarries |
Hoist (c) |
e) a strong, large-diameter, heavy steel or fiber rope |
Task 4. Put in the missing words from the box:
A __1 hoist is an automatic device for vertical transportation of ____2 passengers or freight to different levels in a mine. Basic hoists have two important parts: _______ 3 lifting element and power element. The lifting element is either chain type or wire rope type wrapped around a___4 drum to move a skip. Power element is started by electric ____5 motors , direct current drives utilizing solid-state converters (thyristors).