Máy
cán được sử dụng rộng rãi trong ngành công nghiệp cao su. Các tai nạn liên quan
đến máy cán chủ yếu là bị cuốn vào trục cán đang quay trong lúc vận hành, sửa
chữa, bảo trì. Nguy cơ xảy ra các tai nạn liên quan đến việc sử dụng máy cán được
trình bày cụ thể sau đây.
…
The
problem of mill safety is not a simple one; there are several major issues
involved:
·
mill height,
·
the size of the operator,
·
auxiliary equipment,
·
the way the mill is worked,
·
the tack or stickiness of the stock,
· stopping
distance.
Mill
height makes a difference as to where the operator works the mill. For mills
less than 1.27 m high, where the height of the operator is greater than 1.68 m,
there is a tendency to work too high on the mill or too close to the nip. This
allows for a very short reaction time for the automatic safety to stop the
mill.
The
size of the operator also dictates how close the operator needs to get to the
mill face to work the mill. Operators come in many different sizes, and often
must operate the same mill. The majority of the time on adjustment is made to
the mill safety devices.
Auxiliary
equipment such as conveyors or loaders can often conflict with safety cables
and ropes. Despite codes to the contrary, often the safety rope or cable is
moved to allow for the operation of the auxiliary equipment. This can result in
the operator working the mill with the safety cable behind the operator’s head.
While
the height of the mill and the auxiliary equipment have a part in the way a
mill is worked, there are other factors which enter into the picture. If there
is no mixing roll below the mixer to distribute the rubber evenly on the mill,
the operator will have to physically move the rubber from one side of the mill
to the other by hand. The mixing and moving of the rubber exposes the operator
to increased risk of strain or sprain injuries in addition to the hazard of the
mill nip.
The
tack or stickiness of the stock poses an additional hazard. If the rubber
sticks to the mill roll and the operator has to pull it off the roll, a body
bar becomes a safety hazard. Operators of mills with hot rubber have to wear
gloves. Mill operators use knives. Tacky stock can grab a knife, glove or bare
hand and pull it toward the running nip of the mill.
Even
an automatic safety device will not be effective unless the mill can be stopped
before the operator reaches the running nip of the mill. Stopping distances
must be checked at least weekly and the brakes tested at the beginning of each
shift. Dynamic electrical brakes must be checked on a regular basis. If the
zero switch is not adjusted properly, the mill will move back and forth and
damage to the mill will result. For some situations, disc brakes are preferred.
With electrical brakes a problem can arise if the operator has activated the
mill stop button and then tried an emergency mill stop. On some mills the
emergency stop will not work after the mill stop button has been activated.
…
Trích
đăng từ sách Health and Safety in the Rubber
Industry, Naesinee Chaiear, Smithers
Rapra Press, 2001, trang 11 – 13
(vtp-vlab-caosuviet)
