System for accurately weighing solids and control mechanism for same

1. A system for accurately weighing a mass of material, comprising:

a) a closed chamber ( 20 ) including a chamber gas inlet ( 22 ) and a gas outlet ( 24 );

b) an inert gas supply under positive pressure connected to the gas inlet ( 22 );

c) a scale ( 30 ) disposed in the closed chamber ( 20 ) ; and

d) a vacuum powered pressure regulator ( 100 ) operatively connected to the gas outlet ( 24 ) to maintain a predetermined pressure level within the closed chamber ( 22 ) and to substantially inhibit pressure fluctuations within the closed chamber ( 22 ), wherein the vacuum powered pressure regulator ( 100 ) comprises:

a container including a compartment ( 110 ) partially filled with a liquid ( 111 ) so as to define a head space above the liquid ( 111 );

a vacuum supply in fluid communication with the head space;

a first dip tube ( 117 ) having one end extending into the liquid ( 111 ) and an opposite end operatively connected with the gas outlet ( 24 ); and

a second dip tube ( 122 ) having one end extending into the liquid ( 111 ) and an opposite end operatively connected to a container vent.

2. The system of claim 1 , wherein the container includes a liquid trap zone ( 112 ) disposed between the compartment ( 110 ) and the chamber gas outlet ( 24 ).

3. The system of claim 2 , wherein the container includes a second liquid trap zone ( 114 ) disposed between the compartment ( 110 ) and the container vent.

4. The system of claim 1 , wherein the system is capable of measuring a 20 kg mass of material within +/−0.1 gm.

5. The system of claim 1 , further comprising a receptacle ( 40 ) connected to the scale ( 30 ).

6. The system of claim 5 , further comprising a material supply line ( 29 ) disposed above and physically unconnected from the receptacle ( 40 ), and a material dispensing conduit ( 50 ) disposed below and physically unconnected from the receptacle ( 40 ).

7. A process for accurately weighing and dispensing a mass of material, comprising the steps of:

i) providing a closed chamber ( 20 ) including a scale ( 30 ) disposed therein and a receptacle ( 40 ) operatively connected to the scale ( 30 );

ii) adding a mass of material to the receptacle ( 40 ) from a material supply line ( 29 ) that is disposed above and physically unconnected from the receptacle ( 40 );

iii) controlling pressure within the closed chamber ( 20 ) through operation of a vacuum powered pressure regulator ( 100 ) connected to the closed chamber ( 20 ); and

iv) dispensing the mass of material from the receptacle ( 40 ) via a dispensing conduit ( 50 ) disposed below and physically unconnected from the receptacle ( 40 );

wherein said vacuum powered pressure regulator ( 100 ) comprises:

a) a compartment ( 110 ) partially filled with a liquid ( 111 ) so as to define a head space above the liquid ( 111 );

b) a vacuum port ( 132 ) in fluid communication with the head space, so that an environmental pressure of the head space is negative;

c) a vent line ( 120 , 121 , 122 ) for regulating pressure in the head space, the vent line ( 122 ) adjustably extending into the liquid ( 111 );

d) a process line ( 115 , 116 , 117 ) including a first end connected to the closed chamber ( 20 ), and an opposing second end adjustably extending into the liquid ( 111 ).

8. The process of claim 7 , further comprising the step of:

continuously sweeping the closed chamber ( 20 ) by introducing an inert gas under positive pressure into the closed chamber ( 20 ) through a gas inlet ( 22 ).

9. The process of claim 8 , further comprising the step of:

continuously exhausting the inert gas from the closed chamber ( 20 ) through a gas outlet ( 24 ).

10. The process of claim 7 , wherein the vacuum powered pressure regulator ( 100 ) further comprises a first liquid trap zone ( 112 ) for the process line ( 115 , 116 , 117 ).

11. The process of claim 10 , wherein the vacuum powered pressure regulator ( 100 ) further comprises a second liquid trap zone ( 114 ) for the vent line ( 120 , 121 , 122 ).

12. The process of claim 7 , wherein the process is capable of measuring a 20 kg mass of material within +/−0.1 gm.

13. A process for accurately weighing a mass of material, comprising the steps of:

i) providing a closed chamber ( 20 ) including a scale ( 30 ) disposed therein and a receptacle ( 40 ) operatively connected to the scale ( 30 );

ii) adding a mass of material to the receptacle ( 40 ) from a material supply line ( 29 ) that is disposed above and physically unconnected from the receptacle ( 40 );

iii) continuously sweeping the closed chamber ( 20 ) by introducing an inert gas under positive pressure into the closed chamber ( 20 ) through a gas inlet ( 22 );

iv) continuously exhausting the inert gas from the closed chamber ( 20 ) through a gas outlet ( 24 ); and

v) controlling a pressure level within the closed chamber ( 20 ), when continuously exhausting the inert gas, to within about 0.125 kPa.

14. The process of claim 13 , wherein the pressure level within the closed chamber ( 20 ) is controlled within about 0.062 kPa.

15. The process of claim 13 , wherein the pressure level within the closed chamber ( 20 ) is controlled within about 0.031 kPa.

16. The process of claim 13 , wherein the process is capable of measuring a 20 kg mass of material within +/−0.1 gm.