HEM AIR HEATER

The 'HEM' series of indirect fired heaters are designed to fire applications were process air is to be heated from ambient temperatures up to the process plant requirements.
The robust construction of the units make them an ideal heat source for many industrial oven and heating systems; typical applications include spray booths and drying rooms.

Operating air temperatures up to 300C can be accepted.
Heater capacities of thermal outputs from 60kW to 1000kw are available; special units to meet the requirements of a particular application can be supplied.

The standard HEM heaters consist of a heat exchanger mounted inside a flanged and insulated steel duct section.
The heat exchanger section is generously rated for heat transfer surface area and consists of a stainless steel combustion chamber and tube assembly.
The combustion chamber and the tube bank assembly are independently mounted to cater for differential expansion.
The outer casing of the HEM unit is manufactured from standard carbon steel and is of a double skinned, thermally insulated construction; insulation is available either 50mm or 100mm thickness depending on application requirements.
The complete inner assembly can be withdrawn on its frontplate for repair or servicing; the tube banks are fitted with an end inspection cover to facilitate cleaning.
In general HEM heaters are designed for a nominal temperature rise of 45C at the specified nominal air flow; however this will depend on application and heater selection (see information sheets).

If in doubt concerning the suitability of a HEM unit for a specific application - consult sales office.

BURNER ASSEMBLIES

Each HEM unit is supplied with a prepackaged and prewired burner assembly which would include all of the necessary burner fuel safety valves, pressure switches and automatic ignition and flame safety equipment.

Most types of flame failure and automatic ignition control units can be supplied; utilising either flame rectification, photo cell or ultra-violet flame sensing equipment.
Burners built to special specifications depending on application and country of installation can be fitted.
Burners packages are fully tested and the operation of all components checked before despatch from the factory.

DIRECTION OF AIR FLOW

Standard HEM heaters are arranged to fire horizontal in the direction of air flow from left to right(SF).
Heater units can be supplied for firing into duct systems with vertical upwards or downwards air flow.
Air flow should be uniform across the air duct, both upstream and downstream of the heater.

TYPES OF CONTROL AVAILABLE

Heaters supplied with oil burners are normally for high-low operation. (on-off on small units)
Most gas burner applications are fitted with modulation burners although high-low can be supplied.

INSTALLATION, COMMISSIONING AND MAINTENANCE

If required a complete delivery, installation and commissioning service can be supplied, including the manufacture and installation of associated steel fabrications and ductwork.

For commissioning and service purposes, units installed above ground level should be supplied with an access platform which should be part of the support steelwork; the platform should be sized for withdrawal of the inner assembly.

An installation and maintenance manual is supplied for all heaters; commissioning must be carried out by competent engineers in accordance with the instructions in the manual.
Maintenance and service contracts are available - this normally includes scheduled site visits by our engineer and the free of charge supply of burner consumables such as ignition electrode and flame rectification electrode.
A selection of information data sheets (C-H2-INF***) are available showing physical dimensions of types of HEM heater and some technical detail.
A selection of complete general arrangement drawings (M3-HEM-) are available.
As our policy is one of continuous improvement we reserve the right to amend specifications at any time without prior notice.

For further information regarding our range of products and services please contact us.