Over the last decade there have been numerous improvements and innovations in in-place recycling equipment, materials and methods made by contractors, equipment suppliers and material suppliers, resulting in a need to revise and update the original BARM. As a result of these numerous advances, the new second edition of BARM is more than just minor edits and revisions; it represents a complete rewrite of the original document.
The second edition of the BARM, or BARM II, remained true to the original concept of first edition, serving as a source of general information on the asphalt recycling and reclaiming strategies of cold planing milling, fine milling and micro milling , hot in-place recycling surface recycling, remixing and repaving , cold recycling cold in-place and cold central plant recycling , and full-depth reclamation pulverization, mechanical, bituminous and chemical stabilization.
Read the Full Article. Android iOS. Skip to content. Water at higher temperatures can be used but flowrates through the equipment must be increased to prevent excessive temperatures in the equipment. Laboratory drain A suitable sink or floor drain is required to dispose of the water exiting the apparatus. As the cooling water used in this unit is only warmed in the recycle loop and does not become polluted, the water can be recycled provided that the capacity of the system is large enough to minimise temperature rise as the various tests are performed.
A drain valve in the base of the plinth on the left-hand side also requires connection to a sink or floor drain and is normally left open. This drain allows any water spilled on the plinth top to be drained from the collecting channel in the plinth top. Full instructions about enabling the port are included in the Help menus.
Place the support plinth in a suitable location on a firm work surface adjacent to a mains electrical socket. Do not connect the electrical supply at this stage. The equipment will also require permanent connection to a cold water supply and a drain so this should be considered when choosing a suitable location. Carefully remove any transit packaging, taking care not to discard any of the loose items.
The equipment is supplied fully assembled and ready for operation with the exception of the clear acrylic reservoir that is packed separately to avoid damage in transit. Place the reservoir on the support bracket that is located behind the electrical console on the plinth top. Note: When commissioning the TH4 apparatus, it is strongly recommended that flow readings are taken using the built-in console display and NOT the optional data logging software.
The maximum flow rate measurable by the software is restricted due to signal voltage limitations. Ensure that the flexible pipe is connected between the quick release fittings 14 in the recycle loop. Close the cold water flow control valve Connect the cold water inlet 4 to the cold water supply using flexible tubing not supplied.
Secure the tubing to the inlet using a pipe clip. Connect the hot water outlet 6 to a suitable drain using flexible tubing not supplied.
Turn on the cold water supply. Set the selector switch 22 on the console to position F1. Open the cold water flow control valve 12 fully. Pull the grey knob on the pressure regulator 17 upwards — towards the right — then adjust the regulator until the display 21 indicates 3. Push the grey knob on the pressure regulator down to lock the setting. With water flowing through the apparatus to drain, half-open the recycle flow control valve 13 then start the circulating pump using the switch 25 on the console.
Slowly open then close the recycle flow control valve several times to force water through the pump bypass 9 and remove all air from the pipe loop. Allow water to flow through the flow loop until all air has been expelled. Set the selector switch 22 position F1. Adjust the cold water flow control valve until the display 21 indicates 2. Set the selector switch 22 to position F2. Adjust the recycle flow control valve 13 until the display 21 indicates 2.
Set the selector switch 22 to position T1 and observe that the display 21 indicates a sensible temperature for the water oC. Check that T2 and T3 are the same no heating. The protection circuit will automatically restore power to the heater when normal operating conditions are restored - by turning on or increasing the flow of cold water through the equipment.
Observe that the temperature of the water in the loop gradually rises and stabilises at an elevated value. Switch off the heater and observe that the temperatures gradually return to ambient values. Check operation of the reservoir as follows: Close the cold water flow control valve 12 and switch off the heater and circulating pump. Remove the loop of flexible pipe from the quick release fittings 14 by pressing the button on each fitting. Remove the reservoir 18 from its storage bracket at the rear of the equipment and connect it to the quick release fittings.
Ensure that the reservoir is located correctly over the two fittings then press downwards until the fittings latch. Remove the air bleed screw located on top of the clear acrylic reservoir. Open the cold water flow control valve 12 fully to allow water to flow through the apparatus to drain. Half-open the recycle flow control valve 13 then start the circulating pump. While the reservoir is filling with water adjust the position of the recycle flow control valve to ensure that the clear stand-pipe inside the reservoir remains filled with water if the level falls near to the bottom close the recycle valve until the stand-pipe remains filled.
When the level inside the reservoir is above the stand-pipe refit and tighten the air bleed screw. Close the cold water flow control valve and switch off the circulating pump. Remove the air bleed screw on top of the reservoir, open the drain valve at the rear of the apparatus left hand side of heater assembly then allow the reservoir to drain. When empty the reservoir can be removed by pressing the catch on both quick release connectors at the same time.
The reservoir should be replaced on the bracket at the rear of the console. The air bleed screw should be replaced on the top of the reservoir. The flexible pipe should be connected between the two quick release connectors. Refer to the Operation section for further information. If viewing this Instruction Manual via Help Text in Armfield Software refer to the printed version of the manual for these diagrams. Rotate the knob anticlockwise to decrease the flow, clockwise to increase the flow.
Priming the flow loop When not using the clear acrylic reservoir Ensure that the loop of pipe is fitted between the two self-sealing fittings Slowly open then close the recycle flow control valve 13 several times to force water through the pump bypass 9.
Priming the flow loop When using the clear acrylic reservoir Ensure that the reservoir is securely fitted by pressing it down onto the self-sealing fittings until they both latch. Ensure that with water is flowing through the apparatus to drain.
Remove the air bleed screw located on the top of the clear acrylic reservoir. Open the recycle flow control valve 13 half-way then operate the pump and allow the vessel to fill with water.
When the reservoir has filled to a level above the stand-pipe replace and tighten the air bleed screw. Slowly open then close the recycle flow control valve several times to force water through the pump bypass. Setting and measuring the water flowrate Through flow Set the selector switch 22 position F1. Adjust the cold water flow control valve 12 until the display 21 indicates the required 'through flow' in the range 1.
Do not vary the flow by changing the setting of the pressure regulator. The minimum 'through flow' F1 is limited to 1. Note: When fully primed, the inflow F1 and outflow F2 must always be the same. Setting and Measuring the water flowrate Recycle flow Set the selector switch 22 to position F2. Switch on the recycle pump switch 25 then adjust the recycle flow control valve 13 until the display 21 indicates the required recycle flow in the range 1. The minimum 'recycle flow' F2 is limited to 1.
Applying a step change to the heater The heater 11 in the recycle loop can be switched on or off as required to create a step change of temperature in the system. Note: If the heater is switched on with no water in the system or the flow of water is not adequate then a protection circuit will operate and turn off the power to the heater to prevent damage to the equipment.
Measuring the temperatures in the system Set the selector switch 22 to position T1, T2 or T3 as required. The display 21 indicates the appropriate temperature in the range 4 — oC. Maximum operating temperature is typically 70oC at T2. Operation outside of these conditions may result reduced performance, damage to the equipment or hazard to the operator. Indoor use; b. Altitude up to m; c. Pollution degree 2.
Normally only nonconductive pollution occurs. Temporary conductivity caused by condensation is to be expected. Typical of an office or laboratory environment.
Regular maintenance of the equipment is the responsibility of the end user and must be performed by qualified personnel who understand the operation of the equipment. General In addition to regular maintenance the following notes should be observed: 1.
The equipment should be disconnected from the electrical supply when not in use. The pipework and reservoir associated with the recycle loop and the channel in the support plinth base should be drained after use.
Drain valves located at the rear left-hand side and front right-hand side of the pipework on the plinth top allow the front and rear sections of the flow loop to be drained after use.
Note: Before removing the reservoir close the cold water flow control valve, switch off the circulating pump, open the rear drain valve then unscrew the bleed screw on the top of the reservoir until the reservoir has drained. Press the latches on both quick release fittings at the base of the reservoir to detach it. The various plugs and sockets on the equipment should be given a light spray of de-moisturising lubricant at regular intervals to ensure smooth and reliable connections.
If the RCD does not trip when the TEST button in pressed then the equipment must not be used and should be checked by a competent electrician. Re-calibration of the thermocouple conditioning circuits. The thermocouple conditioning circuits which provide readings from the three thermocouples fitted to the flow loop are located on a PCB inside the electrical console.
These circuits are calibrated before despatch and should not require recalibration. However, should recalibration become necessary the appropriate zero and span potentiometers can be located using the diagram below.
A Type K thermocouple simulator should be connected to each socket in turn on the front of the console and the corresponding zero and span potentiometers adjusted to calibrate the circuit.
If a thermocouple simulator is not available then a Type K thermocouple E. However, in the event of an electrical problem, it may be necessary for a competent electrician to gain access to the inside of the moulding as follows: Ensure that the equipment is disconnected from the electrical supply not just switched off. Disconnect the cold water supply.
Unscrew the channel drain valve located in the recess at the left-hand end of the moulded plinth. Disconnect the electrical leads to the heater and circulating pump from the electrical panel at the rear of the plinth. Carefully remove the front panel from the electrical console by unscrewing the four fixings.
Disconnect the electrical connections between the top and bottom plinth sections by disconnecting the appropriate connectors. Unscrew the six fixings around the periphery of the plinth top. Carefully lift the top moulded section away from the bottom moulded section and place the top section in a suitable location.
The electrical circuits inside the bottom moulded plinth section are accessible for working on. A circuit diagram showing the mains and DC electrical circuits inside the plinth is included in Electrical Wiring Diagram to assist in fault finding. Should it be necessary to remove the PCB from inside the electrical console then the PCB Connections diagram below shows the location and function of the electrical connectors on the PCB to aid re-assembly.
Re-assembly of the equipment is the inverse of the above instructions. Due to voltage limits on the sensor signals, the software cannot measure flow rates above 3. Flow rates higher than this will be displayed as 3. When operating at flows close to this value, it is recommended that the flow rate displayed on the integrated control console is also monitored, to ensure that any deviation above the 3.
Nomenclature The following nomenclature has been used for the theory presented in this manual: Name Symbol Unit Type Definition Used in Time taken for a given volume of Time t s theory water to pass a given point. Diameter of the pipe at the point of Diameter of d m Provided flow measurement. Enthalpy of water. Rate of heat transfer from heater Heat transfer and pump to fluid. Theory The recycle loop apparatus may be simply modelled as a generic system, with an inflow from the water supply and an outflow to the drain.
Under steady state conditions, for equilibrium, the rate of mass flow entering a system must equal the rate of mass flow leaving a system. The mass flow rate, Qm, is the mass of fluid passing a point in a given time. Equipment Set Up To set up the recycle loop apparatus, you will need to complete the recycle loop. Use the short length of tubing provided to connect the two self-sealing couplings on the unit. Check that the inlet is connected to the water supply, and the outlet to a suitable drain.
Check that the heater switch and the pump switch are both in the off up position. Switch on the console, and fully open both the inlet and recycle loop valves. Use the rotary selector switch on the console to display the output from the inlet flow meter F1 on the digital meter. Turn on the water supply and increase the pressure slowly to give an indicated flow rate of approximately 3.
Switch on the recycle pump, and allow about five minutes for the air in the system to disperse. Open and close the recycle loop valve a few times to help in this process. Switch off the recycle loop pump and close both valves until you are ready to begin the experiment. Use the inlet flow temperature and the table provided in Data Sheet 1 to find the inlet flow density. Change the display to give the output from the recycle loop flow meter F2. Wait for the flow velocities to stabilise.
Record the flowrates for the inlet, the outlet, and the recycle loop. Continue to open the recycle loop valve to give recycle flow rate increments of approximately 0. Repeat the whole experiment for a range of inlet flowrates. Do not exceed 3. Does this agree with the theoretical result for the steady state mass balance? Method To vary the flow rate through a recycle loop, whilst heating the recycle fluid and observing the temperatures of the inlet, outlet, and recycle loop flow.
Procedure Open the inlet valve to give an inlet flow rate of approximately 1. Open the recycle loop valve, and then switch on the recycle loop pump.
Switch on the heater. Record the inlet flow rate and temperature. These can be assumed to be constants for each set of results. Record the recycle loop flow rate, and the recycle loop and outlet temperatures. Open the recycle loop valve in stages, to give a series of recycle rates. At each step, record the recycle loop flow rate and temperature, and the outlet temperature. H can then be found by obtaining the specific heat of water at the recycle temperature, using the table provided in Data Sheet 2.
Conclusion Does the recycle rate effect the temperature of the outlet flow, for constant inlet flow rate? Comment on the heat input obtained from the graphs. Is there any noticeable heat difference between the inlet and outlet flow temperatures when the heater is switched off? What does this suggest about the heat input from the recycle loop pump? The apparatus takes several minutes to respond. The time constant is independent of the heater power and the recycle rate, but depends on Qvi, the inlet flow rate, and the volume of the system, V.
Check that the inlet pipe is connected to the water supply, and the outlet pipe runs to a suitable drain. Turn on the water supply, wait until water is flowing through the system, and then switch on the recycle loop pump.
Open and close the recycle loop valve a few times to help disperse any air present. Wait a few seconds until all the air is pumped from the system, then switch off the recycle loop pump and close both valves until you are ready to begin the experiment.
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