Miniature Functional Toggle Clamp
POC developed to demonstrate automatic switch between LPG and a kitchen waste Biogas, where biogas is generated locally. The system automatically switches to Biogas when it is available, and LPG if not availble, to the same stove!

Background

Biogas is generated at a relatively low pressure than the pressure of LPG in the kitchen cooking gas cylinders. Due to this separate stoves with different burner designs are used for both Biogas and LPG. However, the kitchen space is difficult to find for two stoves in most Indian kitchens, and so this POC by NIE-CREST was initiated to experiment if same stove can be used for both LPG and Biogas with seamless switching between the two, so the adoption of kitchen waste LPG Gas systems are accelerated in India.

NIE-CREST is a department in The National Institute of Engineering (NIE), Mysuru, which promoted adoption of green technologies, ecofriendly technologies, altermnate fuels, bio-diesels and a host of other innovative systems to make our lives more eco-friendly and sustainable.


Block diagram explaining how the LPG-Biogas switcher works

Product and Technology Description

The system tries to adopt a standard LPG Gas stove to use both Biogas and LPG. The system had adequate sensors to detect LPG Levels and automatically switch to use Biogas when it is available, and switch over seamlessly to LPG when biogas is exhausted without the user noticing the difference.

The concept was envisaged by NIE-CREST, Mysore who are the authority on Biogas plants in and around Mysore region.

The internal hardware that does the work
developed at Ideas Unlimited.

The completed Prototype system.
Two inlets on right side and one outlet on the left.

The front panel visual interface for the system,
along with a manual override button.

The inside of the Automatic switching unit.
Flow control valves, Flow Sensor switch, Piping and connections
and the electronics associated with it. Developed by Ideas Unlimited, Mysore

Working Sequence: First blower switches on, then LPG line
is connected to the Gas Stove and once stove is ignited and ready
seamlessly switches over to biogas plant.
Indicator on left shows the Biogas levels.
The LPG stove design differs slightly in the nozzles and burner design because of the higher pressure inside an LPG-Cylinder. Biogas stoves operate on a relatively lower pressure and so have a different kind of design.

In this regard NIE-CREST got a stove design modified with one of the LPG experts so that the same stove can be used for both LPG and Bio-gas and we developed the atomatic system that smartly switches between LPG and Biogas by monitoring the conditions.

A typical Kitchen-Waste Biogas plant developed by NIE-Crest can be placed in the corner of the site of a small 30'X40' house plot and the kitchen waste generated in one day can be used to fuel an afternoon's cooking comforably and more! The biogas plant if maintained continuosly can feed enough gas for cooking one to two time food per day regularly.

Initially the system detects switching on of the gas stove by using a flow sensor switch, and connects the LPG cylinder to the gas stove. LPG also helps in quicker and hassle free ignition of the gas stove. Simaltaenously the system switches on the Air Blower connected to the biogas plant

Then once the stove is ignited within a few seconds, the system switches over to the Biogas line supply instead of LPG.

In case the biogas levels in the biogas plant are insufficient or very low, the system switches over to LPG so the cooking in kitchen is not disturbed. It simaltaneously switches of the air blower as well.

The system developed as a prototype worked reasonably well,though the biogas tank level system required some improvements.