ATLAS TILE / COOLING UNIT FOR TEST BEAM IN EHN1

Technical specifications - Instruction manual
ATLAS TILE - TEST BEAM COOLING UNIT
*Objectives* *This document is intended to anyone who may use the cooling unit* *Abstract* A cooling unit has been designed and manufactured to cool down the electronic of the ATLAS TILE modules on the test beam in Hall EHN1. Technical characteristics, LCS v.2 functions and instruction manual are given in this document.
*Prepared*				*Verified*				*Approved*
*By:*	BONNEAU Pierre				*By:*	Reviewer		*By:*	Approver
*Date:*	2001/04/19				*Date:*	200Y/MM/DD		*Date:*	200Y/MM/DD
*Distribution* List

*History of Changes*
*Rev. No.*		*Date*	*Pages*				*Description of Changes*

Table of contents

1. Introduction *

2. Technical specifications *

2.1 Fridge circuit *

2.2 Secondary circuit *

2.3 Controls *

2.3.1 P.L.C. *

2.3.2 Other controls *

2.3.3 Remote controls *

2.3.4 Alarms and safety *

3. instructions * 3.1 LCS v.2 operating principle *

3.2 Operation *

3.3 Operating functions *

3.4 Starting procedure *

3.5 Testing *

4. Annexes * 4.1 Mechanical drawings *

4.2 Photos *

4.3 Electrical drawings *

4.4 Manufacturer manuals *

Introduction

This cooling system is designed to evacuate 2 kW from the modules of the TILE CALORIMETER of ATLAS during their calibration. Required temperatures are Inlet 18°C to Outlet 20°C. The unit is a closed liquid circuit working according to the LCS v.2 principle and connected to a primary circuit through and heat exchanger. A small Programmable Logical Controller controls the operation.

Technical specifications

Fridge circuit

The primary (fridge) circuit is a closed evaporative circuit with a hermetic compressor, an air-cooled condenser, a refrigerant tank and a coaxial evaporator. The liquid refrigerant pressure is reduced through an expansion valve at the entrance of the evaporator.

The compressor is equipped with oil sight glass, crankcase heater and 3 ways valves. It is protected on both high and low pressure by a switch automatic reset.

Fridge power: 2000 W with evaporative temperature +10°C and condensing temperature +40°C.

Refrigerant: R134a (HFC). A filter drier (molecular sleeve 3A) and a sight glass control the humidity of the fluid.

Secondary circuit

The secondary is a closed liquid circuit connected to the tubes (heat exchanger) inside the modules to be cooled. A circulator pump moves the fluid from a pressurized storage tank to the exchangers through resistance heater and the coaxial evaporator.

The operating pressure and flow are controlled by the storage tank pressure and the circulator speed.

The pressure of the storage tank is controlled by a membrane vacuum pump and 2 vacuum switches:

Vacuum pump: KNF N026ANE - max. flow: 20 [l/mn] / min.pressure: 100 [mbar.a]

Vacuum switch: HUBA 625.64301121 - Range -50/-600 [mbar]

Magnetic drive centrifugal pump associated with a variable speed control (3 phase frequency converter): Flow max: 1 m3/h at head max 6m.

Iwaki MD-70R

An autotuning PID controller adjusts the temperature of the fluid by regulating the electrical resistance heater from a RTD Pt100.

Resistance power: 3 kW.

Temperature controller: CAL 3300 PID autotuning

LCD display

Sampling cycle 2 sec.

Accurency 0.25% ± 1°C

Output SSR drive (pulse voltage)

Evaporator: Coaxial finned copper tube WIELAND Type WKE 10.

A discharge valve DANFOSS AVDO between outlet and return manifold controls the differential pressure and assumes a minimum flow in the system to prevent any ice in the evaporator.

Storage tank: Stainless steel 80 liters capacity with visual liquid level and a capacitif switch float level.

Fluid: Demineralized water.

Outlet and inlet manifolds in the rack for 6 channels. Each channel is equipped vith ON/OFF valve and quick disconnect shut off valve.

Controls

P.L.C.

A small Programmable Logical Controller controls the parameters of the Leakless 2 cooling system and gives alarms:

SIEMENS LOGO! 24[V]

1 terminal LCD display

12 digital inputs

8 output relay

Other controls

1 manometer on the control box for the vacuum in the storage tank.

1 manometer on the control box for the outlet pressure of the pump.

1 show glass on the return line before the tank.

Liquid outlet temperature displayed by the controller on the control box.

Visual liquid level in the tank.

Speed of the circulator adjustable by the variable speed drive.

NTC temperature sensor at the inlet and the outlet of the drawer on each channel. These sensors have to be connected to an ATLAS ELMB to be read by the SCADA system.

Remote controls

Remote controls: 2 connectors available on the control box (see 186/9a.0205):

From the temperature controller:

Alarms.

From the PLC !LOGO:

Common signal for the 5 alarms managed.

Vacuum pump ON; it give the possibility to record the pumping time and their frequency, therefore the evolution of the leaks with the time for the whole system.

Alarms and safety

Alarms

Alarms managed by the PLC !LOGO (lamp flashing on the control box with special identification for each. See label on the control box or message on the !LOGO display):

Switch float level on the tank.

High pressure switch on the tank.

Protection on the vacuum pump.

Default on the frequency controller / main protection

Other alarms for internal use only (automatic or manual reset):

High / Low pressure on the fridge.

High temperature switch off on the heater.

Safety

Relief valve on the storage tank: 1mbar.a.

Adjustable thermostat switch-off on the heater: 0/100°C.

HP/LP pressostat on the fridge compressor.

instructions

LCS v.2 operating principle

The liquid is held in a storage tank (3) maintained below atmospheric pressure by a vacuum pump (2). A check valve discharges any excess air in the event of drainage and prevents the pressure in the storage tank from rising above atmospheric pressure. The liquid is moved into the exchangers (1) incorporated through the electronic system by a circulator (4).

The pressure at the various points of the circuit depends on the head losses and hydrostatic pressures.

At start-up, if the pressure in the storage tank is not low enough the vacuum pump is activated. While the later is in operation, in the event of an air intake for instance, the circulator cannot run. The pressure throughout the circuit still equal to the pressure in the storage tank.

Operation

The liquid is held in the storage tank below atmospheric and this pressure is controlled by the vacuum pump via a pressure switch.

A second switch fixes a maximum pressure point to stop the circulator (case of main leak).

The whole system is stopped and needs to be resetted if the vacuum pump works for more than 20 minutes.

If the pressure value is contained between the operating setting point and the upper point (switching difference) the circulator and the temperature regulation (controller and heater) run. The vacuum pump and the electrovalve are off. This is the running mode.

If the pressure goes higher than the upper point of the vacuum switch the vacuum pump starts, the 3 ways electrovalve is actuated after 2 sec. and the pressure goes down to the lowest setting point pressure (the minimum admissible pressure). The circulator and the temperature regulation are still running.

A manual vacuum pump switch lets the operator to active it in order to gas out the circuit or to fill the storage tank with fluid (3 positions switch on PPV).

The outlet pressure of the circulator is controlled by a pressure sensor via the PID 3-phase frequency converter. The set point can be adjusted by a manual potentiometer (Pump setpoint).

Operating functions

The circulator is on if:

The pressure in the circuit is correct or the vacuum pump works for less than 10 mn.

The temperature switch off of the heater is not actived.

The liquid level in the storage tank is correct.

The temperature regulation is on if:

The pressure in the circuit is correct or the vacuum pump works for less than 10 mn.

The temperature switch off of the heater is not actived.

The liquid level in the storage tank is correct.

The fridge is on if:

HP/LP pressostat of the compressor is not actived.

The pressure in the circuit is correct or the vacuum pump works for less than 10 mn.

The temperature switch off of the heater is not actived.

The liquid level in the storage tank is correct.

The temperature liquid is above 10°C in the evaporator.

The vacuum pump is on if:

The pressure in the circuit is higher than the setting point.

The continuous time of pumping is under 10 mn.

Its manual switch is on.

The 3 ways electrovalve is on if:

The vacuum pump is actived since 1 seconde.

Starting procedure

(Assuming the system is leaktight)

Switch on the main power (I) on the control box.

Switch the 3-position switch on ON; the vacuum pump starts; the circulator will start after the pressure in the tank reaches [700mbar.a]. If starting from the atmospheric pressure it will take about 30 [mn].

The pumping time of the vacuum pump is limited to 20 [mn]. If it stops and the fault lamp flashes press the RESET button.

Adjust the outlet pressure of the circulator with the potentiometer PUMP SETPOINT.

To adjust the set point on the temperature controller go to the CAL 3300 instruction manual.

To stop the circulation switch the 3 positions switch on PPV; the system stays under pressure control and the 3 ways valve is closed.

To stop the system switch the 3 positions switch on STOP; the pressure will rise to the atmospheric one depending of the leak rate of the system. One can break the vacuum with the switch valve PURGE on the control box.

Testing

Annexes

Go to 186.9aAnnexes - pdf document

Mechanical drawings
Photos
Electrical drawings
Manufacturer manuals

Manuel LOGO!
Variateur fréquence OMRON
Pressostat HUBA
Temperature controller CAL 3300
Discharge valve DANFOSS AVDO
Pump IWAKI
Vacuum pump KNF
Capacitif switch float level ELITEC