Part B | 12.8
370 Part B Tools and Methods in Marine Biotechnology
sealed with heat-resistant elastic sealant. The coolant
was chosen according to the desired temperature and
for very low temperatures, the hoses connecting the
cooler and the TGB were thermally insulated to avoid
precipitation of moisture and buildup of ice. At the opposite end of the TGB, four electrical heating elements
(6:4 mm diameter 88:9 mm, 200 W) were placed into
6:5 mm diameter holes in the block. The maximum
temperature attainable is 220
ı C and the steepest thermal gradient is 160
ı C, providing 10
ı C temperature
difference between each row of containers. Over the
length of the block, four thermo-probes (PT 100, 60
to C400
ı C) were installed to continuously monitor
the temperature, which were connected to an electronic
multicontroller for on–off switching of the heating
elements.
The HPU (Fig. 12.36) is essentially a back-pressure
system with a constant small leakage. Pressure is created by two HPLC pumps that can operate in a higher
pressure range (from 400 to 600 bar). The pumps
Manometer
16-fold distribution blocks,
leading to pressure vessels
Back-pressure system
Eluent reservoir
Low-pressure
tubing
Pump
Direction of flow
High pressure tubing
Pump
Valve
Fig. 12.36 Schematic view of the high-pressure system. The thin lines are high-pressure connections; the
bold lines are low-pressure connections (after Kallmeyer
et al. [12.71])
run in constant pressure mode with variable flow rate.
In case of any thermal expansion during the warmup, pressure remains below the specified threshold.
The back-pressure system comprises five used HPLC
columns (250 4:6 mm) in line. At 450 bar pressure,
0:70:8 mL leaks through. During the warm-up period, thermal expansion may cause the pressure to rise
faster than the back-pressure system can release it,
therefore opening of one of the connections between the
HPLC columns smoothly increases the outflow of the
system in a controlled manner. After thermal equilibrium is achieved, the connection is fastened again. The
outflow of the back-pressure system flows back into the
eluant vessel for subsequent reuse.
The pressure distribution system consists of pumps
connected to a manifold of valves which allows connection of each pump to any of the three lines of pressure
vessels, or for use of the pumps in parallel. Each line
has a Bourdon-type manometer (16 cm diameter) to
dampen the pulsation of the pump. A custom-made 16fold distribution block connects the pressure containers
of each line to the valve manifold. Small pockets in the
Trolit insulation house the distribution blocks. Pressure
vessels consist of large standard S.S. HPLC columns
(I.D. 20 mm, 120 mm long), one end having a normal
HPLC
1
16
in fitting, the other end closed with a steel cap.
The pressure containers are sealed with copper rings
that last for several incubations but must be replaced periodically. Custom-made screw-cap tubes (O.D. 18 mm,
50 mm long) are used as sample vials, two of which fit
in each pressure vessel, thereby providing exact duplicates in pressure and temperature.
The pressure vessels are placed in a bucket filled
with demineralized water and the sample vials dropped
into them. The caps are screwed on the pressure vessel
under water to avoid trapping of air bubbles. After all
pressure vessels are connected to the distribution block,
50 bar is applied to check for leaks. When no leak is
noted, the vessels are inserted into the TGB and allowed
to attain thermal equilibrium. The buildup of pressure
is carefully monitored and released if necessary, then,
after 12 h, the pressure is set to the desired value.
Parkes et al. [12.72] developed the novel DeepIsoBUG system for handling sediments (that contain depressurization sensitive anaerobic, piezophilic
prokaryotes) under elevated pressure (up to 25 MPa)
for enrichment, growth, and isolation of prokaryotes
at pressures up to 100 MPa. When coupled with acquisition of pressurized subsurface cores using the
HYACINTH pressure retaining drilling and core storage system and the PRESS core-cutting system, Deep-
370 Part B Tools and Methods in Marine Biotechnology
sealed with heat-resistant elastic sealant. The coolant
was chosen according to the desired temperature and
for very low temperatures, the hoses connecting the
cooler and the TGB were thermally insulated to avoid
precipitation of moisture and buildup of ice. At the opposite end of the TGB, four electrical heating elements
(6:4 mm diameter 88:9 mm, 200 W) were placed into
6:5 mm diameter holes in the block. The maximum
temperature attainable is 220
ı C and the steepest thermal gradient is 160
ı C, providing 10
ı C temperature
difference between each row of containers. Over the
length of the block, four thermo-probes (PT 100, 60
to C400
ı C) were installed to continuously monitor
the temperature, which were connected to an electronic
multicontroller for on–off switching of the heating
elements.
The HPU (Fig. 12.36) is essentially a back-pressure
system with a constant small leakage. Pressure is created by two HPLC pumps that can operate in a higher
pressure range (from 400 to 600 bar). The pumps
Manometer
16-fold distribution blocks,
leading to pressure vessels
Back-pressure system
Eluent reservoir
Low-pressure
tubing
Pump
Direction of flow
High pressure tubing
Pump
Valve
Fig. 12.36 Schematic view of the high-pressure system. The thin lines are high-pressure connections; the
bold lines are low-pressure connections (after Kallmeyer
et al. [12.71])
run in constant pressure mode with variable flow rate.
In case of any thermal expansion during the warmup, pressure remains below the specified threshold.
The back-pressure system comprises five used HPLC
columns (250 4:6 mm) in line. At 450 bar pressure,
0:70:8 mL leaks through. During the warm-up period, thermal expansion may cause the pressure to rise
faster than the back-pressure system can release it,
therefore opening of one of the connections between the
HPLC columns smoothly increases the outflow of the
system in a controlled manner. After thermal equilibrium is achieved, the connection is fastened again. The
outflow of the back-pressure system flows back into the
eluant vessel for subsequent reuse.
The pressure distribution system consists of pumps
connected to a manifold of valves which allows connection of each pump to any of the three lines of pressure
vessels, or for use of the pumps in parallel. Each line
has a Bourdon-type manometer (16 cm diameter) to
dampen the pulsation of the pump. A custom-made 16fold distribution block connects the pressure containers
of each line to the valve manifold. Small pockets in the
Trolit insulation house the distribution blocks. Pressure
vessels consist of large standard S.S. HPLC columns
(I.D. 20 mm, 120 mm long), one end having a normal
HPLC
1
16
in fitting, the other end closed with a steel cap.
The pressure containers are sealed with copper rings
that last for several incubations but must be replaced periodically. Custom-made screw-cap tubes (O.D. 18 mm,
50 mm long) are used as sample vials, two of which fit
in each pressure vessel, thereby providing exact duplicates in pressure and temperature.
The pressure vessels are placed in a bucket filled
with demineralized water and the sample vials dropped
into them. The caps are screwed on the pressure vessel
under water to avoid trapping of air bubbles. After all
pressure vessels are connected to the distribution block,
50 bar is applied to check for leaks. When no leak is
noted, the vessels are inserted into the TGB and allowed
to attain thermal equilibrium. The buildup of pressure
is carefully monitored and released if necessary, then,
after 12 h, the pressure is set to the desired value.
Parkes et al. [12.72] developed the novel DeepIsoBUG system for handling sediments (that contain depressurization sensitive anaerobic, piezophilic
prokaryotes) under elevated pressure (up to 25 MPa)
for enrichment, growth, and isolation of prokaryotes
at pressures up to 100 MPa. When coupled with acquisition of pressurized subsurface cores using the
HYACINTH pressure retaining drilling and core storage system and the PRESS core-cutting system, Deep-