Stages of Regulation
In an LPG installation, there can be 1, 2 or 3 pressure regulation stages.
The regulator or the automatic changeover is directly connected to the Cylinder or Tank and reduces the pressure from the vessel directly down to the appliance pressure.
The regulator or the automatic changeover is directly connected to the Cylinder or Tank but reduces the pressure from the vessel down to an intermediate pressure for a second stage regulator application.
The regulator reduces the pressure from the intermediate pressure down to the appliance pressure or to a third stage intermediate pressure.
The regulator reduces the pressure from the second stage regulator pressure down to the appliance pressure normally associated with 3 stage bulk tank installations.
High or Low pressure regulator
For LPG installations the regulators families are generally deﬁned as follows:
High pressure regulators
Regulators delivering an outlet pressure (ﬁxed or variable) higher than 500mbar.
These are deﬁned as Single or First stage regulators generally upto a maximum of 4bar.
Low pressure regulators
Regulators delivering an outlet pressure (ﬁxed, adjustable or variable) lower than 500mbar. These are deﬁned as Single, Second or Third stage.
Automatic Changeover devices
Automatic changeover devices are used with 2 or more Cylinders.
The ﬁrst cylinder (or cylinder bank if using more than 2 Cylinders) is called “service” the second is called “reserve”. The Automatic Changeover ﬁrstly draws the gas from the “service” cylinder. When the “service” cylinder is empty or when its vaporising capacity is not sufﬁcient (for instance, high ﬂow rate during a long time, use of butane-propane mixture, low temperatures, low level in the cylinder, etc….) it automatically changes to and takes the main ﬂow from the reserve cylinder. An indicator, on the device shows that the “service” cylinder is empty.
By using an Automatic Changeover Device you can guarantee continuous flow of Gas without fear of interruption of service to the appliance, maximizing the amount of Gas available in the Cylinders.
There are 2 types of Automatic Changeover Device.
- High Pressure Versions delivering a First stage Intermediate pressure of 1, 1.5 and 3bar for higher capacity and specialist applications for poultry and game rearing brooder heaters or remote cylinder installations
- Low Pressure Versions which are equipped with an integral second stage pressure regulator providing a single stage outlet pressure, normally 37mb, with 29 and 50mb versions also available
The inlet pressure can be expressed in minimum and maximum values. When supplied within the declared range of inlet pressure, the regulator is able to deliver a stable outlet pressure and ﬂow rate declared on the data label. For LPG ﬁrst or single stage regulators, the maximum inlet pressure is 16bar, to ensure the correct flow rates are achieved as deﬁned in the EN standard.
Outlet Pressure – Types and settings
The outlet pressure can be:
- “Fixed”: Outlet pressure is factory preset. The types of regulators with this function are sealed units with no possible chance of adjustment. Typical examples would be certain First stage Intermediate pressure regulators delivering a fixed 0.75bar or 1bar, or Single stage Low pressure regulators typical used in BBQ applications delivering a fixed 29 or 37mb. This will be denoted in the catalogue as (Fixed)
- “Adjustable”: The outlet pressure is factory set but it can be readjusted internally by removing the Cap on the regulator Diaphragm lid. The cap can be hand screwed, or opened only with a special cap removal tool. Compact100 and Compact 800 Automatic changeovers are adjustable via an Allen Key adjustment tool (4mm) underneath a push in grommet on the front of the regulator.
- “Variable”: The outlet pressure can be set using external adjustment methods built onto the regulator, either as a Multi-turn T-Bar, or Knob with hexagonal locking nut, or a single gradient turn 1-10 position head which is not lockable.
- 20-300mbar means a variable setting can be achieved, minimum setting 20mbar, maximum setting 300mbar
- 0.75 (0.5 – 2) bar: The regulator has been preset at the factory to the un-bracketed figure but can be engineer adjusted between the bracketed figure so long as there is a minimum inlet pressure of at least 0.5bar above that required setting.