VJ Series

Packaged Burner

ACE VARIJET Series Burner is the latest development from Advanced Combustion Engineering.

This concept of burner design answers the questions of power, compactness and controllability, which face designers, and specifiers of combustion equipment.

The combination of the most relevant features for current packaged burner designs have been incorporated with the ACE unique modulating system to produce SYSTEM VARIJET.

 

Interchangeable Fans

The interchangeability of combustion fan arrangement and combustion head requirement give the design engineer the key to solving any burner requirement. The question of positive or negative combustion condition, combined with flame shape and size are all accommodated with SYSTEM VARIJET.

Operational requirements of the plant or boiler system can be accommodated with the following various options:

• (A) Fully Modulating (gas and air)
• (B) Modulating Gas Only
• (C) High/Low/Off (gas and air)
• (D) High/Low (gas only)
• (E) On/Off.

 

The VARIJET is a package burner system, which is suitable of process and space heating equipment requirements. A combustion air fan is mounted onto a fuel manifold to which a combustion head is incorporated. The air and fuel (gas or oil) is mixed in the correct proportion to enable combustion to take place.
The flame safeguard monitoring system and automatic ignition system are combined within a control panel, which can be mounted onto the combustion fan arrangement, or remotely mounted to suit required conditions.

 

All burners are manufactured to the highest engineering standards and are individually designed with the latest Computer Aided Design (CAD) System. A complete documented system with full technical file reference enables the burners to conform to the latest European Standards for burner requirement.
This type of burner system is suitable for the following type of typical installation:

• (1) Aluminium Bale Out Furnaces
• (2) Heat Treatment Furnaces
• (3) ladle Pre Heater
• (4) Vat and Tank Heating
• (5) Kilns and Pottery Baking
• (6) Steam & Hot Water Boiler Plant
• (7) Pre-treatment of Metals
• (8) Incineration
• (9) Paint Drying
• (10) Textile Drying, Dyeing and Finishing
• (11) Carpet Backing and Drying
• (12) Plastic & latex Coating

 

Fan Arrangement

The fan casing of the burner is a fabricated steel casing made on precision-engineered jigs and tools in ACE's modern factory unit.
The production is under the closest quality control standards and traceable records.
The fan characteristic is engineered to give the highest possible static pressure development from a compact and adaptable configuration. The whole of the fan assembly is hinged, to allow free and easy access to the inner head assembly.
Following completion of the fan construction, the assembly is finished in a high quality, stove enamelled, acrylic paint finish. The colour finish can be the normal ACE house-red, or changed to suit customers special requirements.

There are five basic fan sizes which take the available fan pressure from 3mb to 35mb, to enable the burner to overcome high furnace resistances. All fans are interchangeable with the burner head and mounting manifold. The fan system can be further enhanced by utilising the variable speed drive system for increased fan pressure.

 

Iris Damper

ACE have proved the IRIS (patented) damper arrangement for modulating burners is the most cost effective method of engineering a modulating combustion system. The burner has been initially designed as a fully modulating system, but with the capability of easily converting to a two stage, high/low or simple on/off
arrangement as required.

 

Ring Damper

For normal on/off or two stage high/low operation, the VJ burner utilises a simple ring style damper on the outside of the motor support and filter housing.
The damper can be either locked into a static position for on/off, or motorised to a high/low/off sequence.

 

Mounting Manifold

The flange arrangement is manufactured from high tensile aluminium, and precision machined to accept the fan assembly and burner combustion head arrangement.
The manifold is hinged at this point to allow the mating flange of the fan assembly to close together and be secured by a two bolt fixing.
The hinge can be either left-hand or right-hand depending on customer requirements.
Draft tubes can be either flange fixed to the mounting manifold, or screw fixed inside the casting depending upon applications.
The length and diameter of the draft tube can be changed to suit individual appliances and flame length preferences.
ACE's in-house manufacture of components, interfaces with the latest CAD generated detailed production requirements. This enables special burner configurations to be accommodated within the normal production throughput.

Combustion Head

ACE have developed the VJ Series of burner to deploy various styles of combustion head arrangement to accomodate any type of combustible gaseous or aqueous fuel. Flame shape, size and luminosity are achieved using a variety of nozzle heads and flame diffuser designs. SYSTEM VARIJET is specially suited to allow for dual fuel firing with rapid change switching capability. The change from gas to oil firing is operated by a simple 3 position switch. ACE have designed the burner head assembly to ensure that the ignition and flame detection probes are located in a secure position, relative to the flame proximity.
The interconnecting HT and probe lead termination are shielded from the flame radiation and are cooled by the combustion air stream.
The combustion head can be accessed by swinging the fan assembly away from the head at the hinge. Easy adjustments can be made to the HT and ionisation probe connections. The head can be removed by removing the locating bolt through the mounting manifold.

 

Gas Train Arrangements

SYSTEM VARIJET burners can facilitate any type of gas train arrangement and safely shut off sequence to suit all types of regulations and standards. The burners are made generally to the current EN 746 or EN 676, and embrace the latest gas appliances directive.
ACE recognise the international appeal of SYSTEM VARIJET and will engineer the gas train arrangement to conform to any particular countries requirement.
The firing rate of the burner generally determines the sophistication of the flame safeguard control system. Each burner and individual gas train are fully wired, soundness tested and operationally test fired prior to certification and despatch. A special reference plate is fitted to each burner for identification purposes including all necessary information.
ACE engineers design the gas train configuration and orientation to suit each particular customers requirements, with special consideration for access and servicing requirements.

 

(A) Fully Modulating

Process burners and some energy conscious space heating applications demand full modulation of gas and air throughout the firing range. The gas modulation control can be accommodated by means of a ball valve and linkage arrangement coupled to the air damper motor, or a combination air gas ratio valve controlled through a pneumatic system from the combustion air fan chamber. Alternative integrated modulating gas and air systems involve a direct
mechanical linkage between a special gas valve and the IRIS air damper. Both gas and air systems are operated in tandem through the common modulating drive system. The linkages are factory preset but can be adjusted on site to match the combustion fingerprint profile.
The fully modulating burner system is the most cost effective for running cost of fuel as well as operational requirements regarding close control of temperature.
This system requires to be operated through a temperature control package, to enable the burner to modulate to the burner output, to the system requirements. SYSTEM VARIJET interfaces ideally with the ACE ERO digital P.I.D. autotune controller. Contact ACE for further details.

 

(B) Modulating Gas Only

SYSTEM VARIJET is available in modulating gas only. In this system the combustion air rate is static with a ring type air damper in a set position. The high fire rate is set to give the correct air to gas ratio before locking of the air ring damper. The gas can be modulated through a motorised gas valve arrangement with the air remaining static. Throughout the turn down from high flame, the burner will run in an excess air condition. Care must be taken to ensure the process is suitable for running with an excess air condition. The burner has limited capabilities and should be limited to the correct settings to ensure low emission values and aldehyde production.

 

(C) High/low/Off (Gas and Air)

For applications involving large mass heat transfer or slower system response time, the high/low burner operation is adequate. This type of burner operates in a two-position flame sequence, the high flame condition down to a lower flame setting. In both cases the ring air damper is set to give the best gas/air setting in both the low and high position. Although not as efficient in operation to the higher specification fully modulating burner, the high/low gas and air burner can provide an acceptable degree of system control. A simple switching of a relay contact or the action of a thermostat is enough of a control signal to enable the burner to switch between the high to low fire mode.

 

(D) High/Low/Off Gas Only

There are applications where cost implications precede the importance of operational characteristics.
The high/low gas only burner works from a simple relay or thermostat contact to switch the burner from a high to low gas firing position.
It should be noted that the lower would work in an excess air condition in its lower settings. Analyses of the products of combustion are required to ensure the burner is acceptable throughout its firing range.

 

(E) On/Off

The operation of this type of burner is as the name suggests. This is the basic original method of operating packaged and pressure jet burners for the past 50 years.
ACE SYSTEM VARIJET has been conceived and designed as a fully modulating burner to meet the ever-increasing demand for efficiency and environmental consideration. It can however be operated in a simple on/off capacity if desired. The choice is available.

 

Variable Speed Drive System

SYSTEM VARIJET has a further endearing feature of Variable Speed Drive System (VSDS). This facility enables the fan speed to be increased by detaching the direct drive motor from the fan impeller. The drive is replaced with a system of pulley drives to increase the fan revolutions.
The fan static pressure characteristic is considerably increased for overcoming high resistance combustion chambers and heat exchangers.

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