FIELD OF THE INVENTION:
The present invention generally relates to sealing/isolation of fluids in the pipeline. More particularly the invention relates to sealing of low pressure producer gas in the pipeline during the idle time of the producer gas users. More particularly, the invention relates to an apparatus for leak-proof sealing of producer gas during idle time in a pipeline.
BACKGROUND OF THE INVENTION:
Producer Gas is generated from the fixed bed coal gasifiers by the reaction of coal, air and steam. To generate producer gas, a mixture of air and steam is lead from the bottom of the fixed bed gasifier to the top through a layer of coal which has been fed from the top of the gasifier. Due to reactions between the coal, air and steam in the gasifier, a mixture of gases consisting of carbon monoxide, hydrogen, methane, carbon-dioxide and nitrogen are formed inside the generator. The gas formed here is called as producer gas. The gas generated from the gasifier is at a pressure of around 40 mm of water column. This gas pressure is further increased to around 300 mm of water column by a gas booster. The Producer Gas is supplied to the end users for the heat treatment application in furnaces and for pre-heating applications in the shop floors. The Producer gas is normally supplied at a pressure of around 300 mm of water column to the end users. For isolation of the producer gas duringidle time of the furnaces, manual operated gate valves are provided. The gas sealing of these type of valves after a period of time is not 100% and there is escape of producer gas through the valves into the furnace causing unsafe conditions inside the furnaces.The following unsafe conditions generally occur in the furnaces during its idle time due to imperfect sealing/isolation of gate valves of the furnaces;

1. Leakage of producer gas into the furnaces, thus causing fainting or giddiness to the persons working inside the furnaces during maintenance.
2. Leakage of producer gas sometimes leads to accumulation of more volume of gas inside the furnaces. During start up firing of the furnace, it leads to huge explosion in the furnace causing damage to manpower and furnace.
To avoid these unsafe conditions there is a need to completely seal/isolate the producer gas in the inlet pipeline of the furnaces during its idle time by an alternative method.
OBJECTS OF THE INVENTION:
It is therefore an object of the invention to propose an apparatus for leak-proof sealing of producer gas during idle time in a pipeline.
Another object of the invention is to propose an apparatus for leak-proof sealing of producer gas during idle time by using high pressure water.
SUMMARY OF THE INVENTION:
According to the invention there is provided an apparatus for leak-proof sealing of producer gas during idle time in a pipeline. In order to implement operation of the apparatus, a U shaped pipeline is introduced at the inlet of the furnaces. The producer gas remains at a pressure of 300 mm of water column in the pipeline. To seal the producer gas which is at 300 mm of water column pressure, from escaping from the U shaped pipeline, water is filled at a height of 750 mm on the either sides of the U shaped pipeline during the idle time of the furnaces. Thus, based on the principle of pressure difference

between water and the producer gas, the gas is 100% sealed/isolated. As a result, the leakage of producer gas into the furnaces is completely eliminated, thus preventing unsafe condition to manpower and also prevents explosion in the furnaces during start up firing. When the furnaces are to be started, the water is to be drained from the U shaped pipeline to allow the producer gas to the furnaces.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING:
Figure 1 shows the schematic arrangement of an apparatus for perfectly sealing the producer gas.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIEMENT OF THE INVENTION:
As shown in figure 1, the apparatus consists of a U shaped pipeline (9) introduced at the inlet of the furnaces with a provision for a water inlet pipeline(2), a water overflow pipeline(4) and a water drain pipeline(7). During normal operation of the furnaces, the water inlet pipeline valve(3), a water drain valve (8) and a water overflow pipeline valve(5) will be in closed condition. The producer gas enters through the producer gas inlet pipeline (1) and passes through the U shaped pipeline (9) and exits through the producer gas outlet pipeline (6).When the furnaces are in idle condition, the water inlet pipeline valve (3) is opened to admit water inside the U shaped pipeline (9).The producer gas is at a pressure of 300 mm of water column in the pipeline. To seal the producer gas which is at 300 mm of water column pressure from escaping from the U shaped pipeline(8), water is gradually filled to a height of 750 mm on the either sides of the U shaped pipeline(9).To ensure that height of the water is filled to a height of 750 mm, the water overflow pipeline (4) is provided at the height of 750 mm from the

base of the U shaped pipeline. The water is gradually filled in the U shaped pipeline and as the water reaches the height of 750 mm, the water overflows through the water overflow pipeline(4) and subsequently through the opened water overflow pipeline valve (5).Once the water gets flowed from the water overflow pipeline (4), the water overflow pipeline valve (5) is closed and subsequently the water inlet pipeline valve (3) is also closed. Thus based on the principle of pressure difference between water and the producer gas, the gas is 100% sealed/isolated. If the furnace has to be put into operation (i.e to restore the producer gas supply), the water drain valve (8) is opened to drain the water from the U shaped pipeline (9) and closed once the water is completely drained.

1. An apparatus for leak-proof sealing of producer gas during idle time in
a pipeline,
- an U shape pipeline introduced at the inlet of furnaces and having a provision for a water inlet pipeline with valve, a water overflow pipeline with valve, and a water drain pipeline with valve;
- wherein the water inlet pipeline valve, water overflow pipeline valve and water drain valve present in the U shaped pipeline during normal operation of the furnace is allowed to remain in closed condition to allow the producer gas entering through the inlet of the U shaped pipeline and exiting through the outlet of the U shaped pipeline to the furnace application;
- wherein the water inlet pipeline valve is gradually opened followed by opening of the water overflow pipeline valve during the furnace idle time, the water drain valve present in the U shaped pipeline remaining in closed condition, wherein when the water gets filled upto a height of 750 mm in the U shaped pipeline, the water overflows through the water overflow pipeline, the water overflow pipeline valve followed by the water inlet pipeline valve are closed, leading to lack-proof sealing of the producer gas due to high pressure of the water compared to that of the producer gas.

2. The apparatus as claimed in claim 1, wherein when the restored back
to normal operation, the water present in the U shaped pipeline is to be drained by opening the water drain valve and once the water is completely drained the water drain valve is closed to resume the normal flow of the producer gas through the U shaped pipeline to the furnace application.