Method for compressing gaseous fuel for fuelling vehicle and device for implementation thereof

1. A method for compressing a gaseous fuel for fueling a vehicle comprising alternately supplying gas into two vertically arranged compressing vessels comprising a first compressing vessel and a second compressing vessel ( 1 and 2 ), each having one neck in the upper part thereof, further compressing the gas and forcing the gas out of said vessels and into a fuel tank of the vehicle by alternately filling the compressing vessels with a working fluid under pressure wherein each cycle comprising alternate filling of the compressing vessels is carried out until said vessels are completely filled with working fluid and the working fluid is alternately pumped from one compressing vessel into the other, wherein, during each cycle, the working fluid travels directly from the first compressing vessel into the second compressing vessel and returns from the second compressing vessel directly into the first compressing vessel without traveling through any intermediate vessels such that said travel of the working fluid is performed until its flow reaches the lower edge of a movable closing element of a shut-off device mounted in said upper neck of the compressing vessel, and displaces said movable closing element in an outlet gas channel of said shut-off device upwards from its lower position, thus closing the seat of a valve of an outlet pipeline for pumping the gas into fuel tank of the vehicle with a tapered portion of said movable closing element before said working fluid reaches said seat of the valve of said outlet pipeline for pumping the gas into fuel tank of the vehicle, said upward movement of the movable closing element activating a fluid-level sensor placed at the outer side of the body of the shut-off device, which generates a Signal for a control unit to change the direction of pumping the working fluid to reverse mode for a new similar cycle of pumping the working fluid from the compressing vessel ( 2 or 1 ) which is completely filled therewith to the other compressing vessel ( 1 or 2 ) which is filled with gas and working fluid, where the amount of said working fluid is enough for compensation of the possible difference of inner volumes of compressing vessels ( 1 and 2 ).

2. A gas-filling device for fueling a vehicle with a gaseous fuel comprising two compressing vessels ( 1 and 2 ) connected through one-way valves to an inlet pipeline for gas supply and an outlet pipeline for pumping the gas into the fuel tank of the vehicle and communicating with each other through a high-pressure hydraulic line and a low-pressure hydraulic line, a hydraulic pump, configured to pump the working fluid alternately from one compressing vessel ( 1 or 2 ) into the other compressing vessel ( 2 or 1 ) and an electric control unit, the hydraulic pipeline being connected to the hydraulic pump, the outlet pipeline for pumping the gas comprising a vehicle fueling connector, wherein each compressing vessel ( 1 and 2 ) comprises a shut-off device integrated with a fluid-level sensor, the latter being placed on the outer side of the body of said shut-off device, said body of the shut-off device being made of a non-magnetic material, said shut-off device being mounted in the neck of the respective compressing vessel ( 1 and 2 ), the shut-off device having a movable closing element which has a tapered upper portion, and said movable closing element is placed in an outlet as channel of the shut-off device with a clearance between it and the walls of said outlet gas channel, said movable closing element being capable of staying in a lower position when the gas flows through the clearance and moving upwards within said channel by the action of the flow of working fluid and closing the gas channel, said movable closing element having a magnetic insert, said fluid-level sensor and said magnetic insert being located at the same level in said lower position of said movable closing element, and said magnetic insert being located out of the area of the fluid level sensor in the upper positions of said movable closing element.

3. The gas-filling device according to claim 2 , further comprising an accumulating vessel connected to the gas pipeline and to the hydraulic pipeline interconnecting the two compressing vessels, the accumulating vessel comprising a shut-off device, mounted in the neck of said accumulating vessel in the same manner as the shut-off devices of the compressing vessels, the shut-off device of the accumulating vessel being connected by a drain tube and a bypass valve to the shut-off device of one of the two compressing vessels for draining the gas from said accumulating vessel to the compressing vessel in case when the fuel tank of the vehicle is full, but there is still some gas in the accumulating vessel in order to achieve completely forcing the gas out of said accumulating vessel by means of completely filling said accumulating vessel with working fluid until the activation of the fluid-level sensor of said shut-off device.

4. The method according to claim 1 , wherein the gas from the two compressing vessels is forced into an accumulating vessel, and further out of the accumulating vessel and the accumulated gas during the fueling of the vehicle is completely forced out of said accumulating vessel into the fuel tank of the vehicle until the accumulating vessel is completely filled with the working fluid, in case when the fuel tank of the vehicle has been completely filled up to the working pressure, and some non-displaced gas is left in the accumulating vessel the filling of accumulating vessel with the working fluid continues but the gas, through the drain tube and through the bypass valve opened by gas pressure, enters not the fuel tank of the vehicle, but the compressing vessel up to the moment of full filling of the accumulating vessel with working fluid response of the fluid-level sensor and full forcing the gas out of the accumulating vessel into the compressor vessel.

5. The gas-filling device according to claim 2 , wherein the two compressing vessels each comprise two necks, upper and lower, the upper necks being connected to the gas pipeline and the lower necks being connected to the hydraulic pipeline.

6. The gas-filling device according to claim 3 , wherein the two compressing vessels and the accumulating vessel each comprise two necks, upper and lower, the upper necks being connected to the gas pipeline and the lower necks being connected to the hydraulic pipeline.