Báo cáo khoa học nông nghiệp " The Low Tech Plant " potx

Treatment vessel Preservative Storage Packet of timber Vac Chest Compressor Air pressure in Valve 3 connecting the treatment vessel to the vacuum pump is opened and the air in the pac

Appendix 1 The Low Tech Plant

FIGURE 1 Operation of the “Low Tech” Plant

Filling the treatment cylinder with preservative

Vent to atmosphere

3 way valve V3

To Vacuum pump V6

V8

V7 V4

V5

V1

V2

Treatment vessel

Preservative Storage

Packet of timber

Vac Chest

Compressor

Air pressure in

Valve 3 connecting the treatment vessel to the vacuum pump is opened and the air in the packet of timber together with the treatment vessel are evacuated The compressor is turned on Valve V1 is opened and air pressure builds up in the top of the preservative storage vessel Valve V2

is opened connecting the preservative storage vessel with the Treatment Vessel containing a packet of timber Preservative is forced from the preservative storage vessel into the treatment vessel covering

Emptying the treatment cylinder of preservative solution

Vent to atmosphere

3 way valve V3

To Vacuum pump V6

V8

V7 V4

V5

V1

V1

Treatment vessel

Preservative Storage

Packet of timber

Vac Chest

Compressor

Air pressure in

Once preservative solution (yellow) covers the timber, V4 and V1 are closed If it is desirable to apply pressure to the treated timber V8 is opened Once the desired pressure or holding time has been achieved V8 is closed V1, V5and V7 are now opened so that the pressures in the preservative storage vessel and treatment vessel equalise Whilst the diagram illustrates that preservative enters the vacuum chest, normally during flooding of the treatment vessel is terminated once the packet of timber is covered with preservative solution This is achieved by placing an automatic sensor above the packet of timber to sense when the pack of timber is covered Preservative should now transfer by gravity back to the storage vessel Flow of preservative back to the treatment vessel can be accelerated by opening V1 and V8 This pressurises the treatment cylinder Once all preservative has been transferred back to the storage vessel, all valves should be shut and the treatment vessel door opened and the packet

of timber removed No final vacuum is applied

Appendix 3 Australian Hazard Classes based on Australian Standard AS 1604

H1 

Low Decay Hazard (eg. Insect  Borer) 

Timber framing not exposed to  weather. 

H2 

infested regions  H3 

Above ground but subject to  weathering 

Fascia boards, weather boards,  external joinery, Glass‐house  components 

H4 

Ground contact (low value)  Agricultural posts, railway 

sleepers  H5 

Ground contact (high value)  Telegraph and Electricity poles  H6 

Exposed in sea water  Marine piles, boat building 

timber in contact with sea‐ water