Switching system for a reciprocating piston pump

1. Field of the Invention

The present invention relates to a pumping system whose output is regulated by gas provided by a gas source.

2. Description of the Related Art

In semiconductor processes, liquid supply is very important. For example, in chemical mechanical polish (CMP) and etching processes, it is very important to provide slurries and etching solutions accurately. Typically, conventional pumps are controlled by signals. Conventional pumps, however, cannot always output liquid stably because of unstable pressure caused by pulse signals. Thus, devices, for example, may be overetched or not etched completely if the liquid supply is not controlled accurately.

In view of this, an object of the present invention is to provide a pumping system with stable output. The present invention uses a plurality of switching devices to stably control the operation of a cylinder pump and its output.

Further, the present invention can control the speed of the cylinder pump by adjusting the gas flow of the needle valve. In addition, the present invention can control the output of the cylinder pump by adjusting the position of the hard stop at the piston linkage.

In the present invention, the pumping system pumps liquid and outputs regulated by gas provided by a gas source. The pumping system has a cylinder pump, a first group of switching devices, and a second group of switching devices. The first group of switching devices enable the cylinder pump to pump the liquid by feeding the gas provided by the gas source into the cylinder pump through a first ventilator according to a first enabling signal, and the second group of switching devices enable the cylinder to output the liquid by feeding the gas provided by the gas source into the cylinder pump through a second ventilator according to a second enabling signal. A control unit is coupled to the first and second groups of switching devices, and controls the gas entering and leaving the cylinder pump and the flow speed of the gas.

For a better understanding of the present invention, reference is made to a detailed description to be read in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram of the pumping system of the present invention;

FIG. 2 shows the control unit and the cylinder pump of the present invention;

FIGS. 3 a and 3 b are operational diagrams of the pumping system of the present invention.

FIG. 1 shows the pumping system 100 of the present invention. The pumping system 100 pumps liquid 300 regulated by gas provided by the source 200 .

The first group of switching devices is composed of switching devices V 1 , V 2 and V 3 . As well, the second group of switching devices is composed of switching devices V 4 , V 5 and V 6 . The switching device V 1 has an input terminal for receiving the gas provided by the gas source 200 , and an enable terminal t 1 for receiving a first enabling signal En 1 from the external circuit. As well, the switching device V 2 has an enable terminal t 2 coupled to the output terminal of the switching device V 1 , and an input terminal for receiving the gas provided by the gas source 200 . Also, the switching device V 3 has an enable terminal t 3 coupled to the output terminal of the switching device V 1 and an input terminal coupled to the liquid source 300 . The switching device V 4 has an input terminal for receiving the gas provided by the gas source 200 , and an enable terminal t 4 for receiving a second enable signal En 2 from the external circuit. As well, the switching device V 5 has an enable terminal t 5 coupled to the output terminal of the switching device V 4 , and an input terminal for receiving the gas provided by the gas source 200 . Also, the switching device V 6 has an enable terminal t 6 coupled to the output terminal of the switching device V 4 and an input terminal coupled to the cylinder pump 10 .

When receiving the first enabling signal En 1 , the switching device V 1 feeds the gas provided by the gas source 200 as a first enabling gas S 1 to turn on the switching devices V 2 and V 3 . Further, the switching device V 2 feeds the gas provided by the gas source 200 as a first driving gas S 11 and the switching device V 3 feeds the liquid from liquid source 300 into the cylinder 10 when receiving the first enabling gas S 1 . Namely, switching devices V 1 , V 2 and V 3 enable the cylinder pump 10 to pump the liquid from the liquid source 300 by feeding the gas from the gas source 200 into the cylinder pump 10 through the ventilator C 1 regulated by the first enabling signal En 1 .

In addition, when receiving the second enable signal En 2 , the switching device V 4 feeds the gas provided by the gas source 200 as a second enable gas S 2 to turn on the switching devices V 5 and V 6 . The switching device V 5 feeds the gas provided by the gas source 200 as a second driving gas S 22 and the switching device V 6 is turned on to output the liquid in the cylinder pump 10 when receiving the second enable gas S 2 . Namely, switching devices V 4 , V 5 and V 6 enable the cylinder pump 10 to output the liquid by feeding the gas into the cylinder pump 10 through the ventilator C 2 regulated by the second enable signal En 2 . A control unit 30 is coupled between the first and second groups of switching devices and the cylinder pump 10 to control the gas entering and leaving the cylinder pump 10 , and the flow speed of the first driving gas S 11 and the second driving gas S 22 .

In this case, the switching devices V 3 and V 6 are normal closed pneumatic valves for liquid, and the switching devices V 1 , V 2 , V 4 and V 5 are normal closed pneumatic valves for gas. In addition, the first driving gas S 11 , the second driving gas S 22 , the first enabling gas S 1 and the second enable gas S 2 from the gas source 200 , for example, are nitrogen gas (N 2 ) or compressed dry air (CDA). Moreover, the first enabling signal En 1 and the second enable signal En 2 are signals from an external circuit, and can also be air signals.

FIG. 2 shows a diagram of the control unit 30 and the cylinder pump 10 of the present invention. The control unit 30 is composed of a manifold 31 , two forward paths 32 and 34 , and two reverse paths 33 and 35 . The manifold 31 is coupled to the switching device V 2 and the switching device V 5 to discharge the second driving gas S 22 when receiving the first driving gas S 11 and to discharge the first driving gas S 11 when receiving the second driving gas S 22 . The forward path 32 and the reverse path 33 are coupled to the manifold 31 , the forward path 32 feeds the first driving gas S 11 into the cylinder pump 10 , and the reverse path 33 outputs the first driving gas S 11 from the manifold 31 . The forward path 34 and the reverse path 35 are coupled to the manifold 31 , the forward path 34 feeds the second driving gas S 22 into the cylinder pump 10 , and the reverse path 35 outputs the second driving gas S 22 from the manifold 31 .

Furthermore, the forward path 32 is composed of a check valve 322 and a needle valve 321 , the reverse path 33 is composed of a check valve 332 and a needle valve 331 , the forward path 34 is composed of a check valve 342 and a needle valve 341 and the reverse path 35 is composed of a check valve 352 and a needle valve 351 . The forward path 32 is connected to the reverse path 33 in parallel, and the forward path 34 is connected to the reverse path 35 in parallel.

The flow directions of first driving gas S 11 and the second driving gas S 22 are controlled to flow in or out of cylinder pump 10 by the forward path, and the reverse path because the check valves 322 , 332 , 342 and 352 are one-way gas valves. Therefore, the present invention can control the flow direction of the first driving gas S 11 and the second driving gas S 22 by a forward connection or a reverse connection composed of check valves. Furthermore, the present invention can also control the flow speed of the first driving gas S 11 and the second driving gas S 22 entering and leaving the cylinder pump 10 by adjusting the flowing apertures of the needle valves 321 , 331 , 341 and 351 . Thereby the present invention can control the pumping speed of the cylinder pump 10 .

The cylinder pump 10 has a gas cavity 11 , a liquid cavity 12 and a piston member. The gas cavity 11 has two ventilators C 1 and C 2 coupled to the switching device V 2 and the switching device V 5 (not shown in FIG. 2) respectively for receiving the first driving gas S 11 and the second driving gas S 22 . The liquid cavity 12 has an input portion 121 and an output portion 122 coupled to the switching device V 3 and the switching device V 6 respectively. The piston member is disposed in the gas cavity 11 and the liquid cavity 12 , and has a piston linkage 13 and a hard stop 14 . The hard stop 14 is disposed between the ventilators C 1 and C 2 to move the piston member along the liquid cavity 12 to pump the liquid from the liquid source 300 and output the liquid regulated by the first driving gas S 11 and the second driving gas S 22 . For example, the hard stop 14 is driven upward when the first driving gas S 11 flows into the gas cavity 11 through the manifold 31 , the forward path 32 and across the ventilator C 1 . Consequently, the piston linkage 13 is driven upward, thereby pumping the liquid into the cylinder pump 10 from the liquid source 300 . The hard stop 14 is driven downward when the second driving gas S 22 flows into the gas cavity 11 through the manifold 31 , the forward path 34 and across the second ventilator C 2 . Consequently, the piston linkage 13 is driven downward, thereby outputting the liquid in the cylinder pump 10 through the switching device V 6 . Moreover, the position in which the hard stop is disposed at the piston linkage 13 can be adjusted regulated by the liquid requirement.

In addition, the pumping system 100 of the present invention may also have two gas adjusters 21 and 22 coupled between the switching device V 2 and the gas source 200 and between the switching device V 5 and the gas source respectively. The gas adjuster 21 adjusts the gas pressure of the gas input to the switching device V 2 , and the gas adjuster 22 adjusts the gas pressure of the gas input to the switching device V 5 .

FIGS. 3 a and 3 b show operational diagrams of the pumping system of the present invention.

Pumping Mode

As shown in FIG. 3 a, first, when receiving the first enabling signal En 1 from an external circuit, the switching device V 1 feeds the gas provided by the gas source 200 as the first driving gas S 1 to output to the switching devices V 2 and V 3 . Thus, the switching devices V 2 and V 3 are both turned on. Consequently, the switching device V 2 feeds the gas provided by the gas source 200 as the first driving gas S 22 , and the first driving gas S 22 also flows into the gas cavity 11 through the manifold 31 , the forward path 32 and across the ventilator C 1 to drive the hard stop 14 upward. Consequently, the liquid from the liquid source 300 can flow into the cylinder pump 10 through the switching device V 3 , and the piston linkage 13 is driven upward, thereby pumping the liquid into the cylinder pump 10 from the liquid source 300 .

Moreover, the gas in the gas cavity 11 , for example the second driving gas S 22 , is discharged by the manifold 31 through the ventilator C 2 and the reverse path 35 when the hard stop 14 is driven upward.

Output Mode

As shown in FIG. 3 b , the switching device V 4 feeds the gas provided by the gas source 200 as the second driving gas S 2 when receiving the second enable signal En 2 from external circuit. Thus, the switching devices V 4 and V 5 are both turned on. Consequently, the switching device V 5 feeds the gas provided by the gas source 200 as the second driving gas S 22 , and the first driving gas S 22 flows into the gas cavity 11 through the manifold 31 , the forward path 34 and across the second ventilator C 2 to drive the hard stop 14 downward. Consequently, the piston linkage 13 is driven downward and the liquid in the cylinder pump 10 is output outside through the switching device V 6 , thereby outputting the liquid in the cylinder pump 10 through the switching device V 6 .

Moreover, the gas in the gas cavity 11 , for example the second driving gas S 11 , is discharged by the ventilator C 2 through the reverse path 33 and the manifold 31 when the hard stop 14 is driven downward.

Thus, the pumping system of the present invention enables the cylinder pump to pump liquid and then output it stably by turning on the switching devices alternately. Also, the liquid proving device can control the pumping speed of the cylinder pump 10 by adjusting the flowing apertures of the needle valves, and can further control the liquid output by adjusting the position in which the hard stop is disposed at the piston linkage 13 .

While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled the art). Thus, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.