Page 648 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

The City & Guilds Textbook: Plumbing Book 1

l Container or hook bin: wood chips can be delivered in a container, often
called a hook bin, where the container forms the fuel storage, which
connects direct to the fuel extraction system. However, these are quite
expensive because at least two bins are required.
l Covered shed: these are relatively cheap and easy to install. Fuel delivery
is quite straightforward. For large stores, the use of manual handling
equipment, such as a front-end loader or mechanical grab, is recommended.
l Hoppers: the hopper is a chute with extra storage capacity. They are
relatively inexpensive to install. The hopper has a ‘V’-shaped floor, sloped at
approximately 40°. This allows the fuel to fall directly onto the boiler feed
screw located at the base of the floor.

25 mm flat wooden
boards

40º
Pressure relief angle

Archimedes–type screw feed
p Figure 10.14 A biomass hopper floor
p Figure 10.15 A biomass silo
l Silos: these are purpose-made rigid structures that are relatively inexpensive
to install but may require special delivery equipment to maintain the
HEALTH AND SAFETY biomass supply.
Safety masks should be l Flexible silos: these are prefabricated, collapsible structures designed
worn when moving wood specifically for smaller installations where access may be restricted, such as
chips or wood pellets as in a confined space or a roof space. The fuel delivery system is usually where
the dust can pose a health the fuel is blown into the hopper. This system uses two hoses: one to blow in
risk. Dust can also pose a the fuel and the other to extract any dust.
significant explosion risk if l Underground bunker: underground bunkers are ideal for larger installations
the area is not ventilated
sufficiently. with easy access for tipper-truck delivery. The feasibility of an underground
bunker will depend upon such factors as ground type, water table and cost.

636

9781510416482.indb 636 29/03/19 9:09 PM