Passive Controlled Degradation Metering (PCDM) Valve
Publication Date: 2019-Apr-30
The IP.com Prior Art Database
The PCDM Valve allows for the passively increase of allowable flow through a Chemical Injection Line. For many Chemical Injection Systems (such as for Scale Inhibitors), the early years of life for the well do not require significant chemical intervention. However, as the well begins to age, the required amount of injected chemicals increases. The PCDM Valve is the means to passively allow the increase of flow through a Chemical Injection System as the demand for further Chemical Intervention increases as a well ages. The device consists of 4 stages that can be reduced depending on the expected well conditions from the customer. The first stage consists of a screw with two parallel threads inside of a matching thread bore. The gap between the ID and OD threads create a very high pressure drop in order to slow the rate of flow bypassing the first stage. The screw is held in place by a shear wire that will maintain the screw position until the rate of flow increases to a point that the pressure drop across the first stage is sufficient to shear the wire. After the wire is sheared the screw then travels down to the second stage. The second stage has the screw inside of a thread bore where one of the two parallel ID threads has been removed. This removed thread allows the same amount of flow to bypass the tool, but the pressure drop require has been reduced. As with the first stage, the screw in the second stage is held in place by a shear wire. Once the required flow rate increases to the point that the pressure drop is sufficient to shear the shear wire, the screw then moves down to the third stage. The third stage has the screw within an ID bore where both of the ID threads have been removed, but the gap between the screw and the ID bore is still small. The removal of both threads allows the same amount of flow across the tool, but again the resulting pressure drop has reduced when compared to the second stage. The screw is held in place again by a shear wire until the required flow rate and pressure drop is sufficient to shear to the fourth and final stage. The final stage of the valve has the screw in an ID bore that has a large gap between the screw and the bore. The larger gap allows the flow for completely bypass the screw, and causes the PCDM resulting pressure drop to reduce to negligible levels. Now the PCDM is completely open, and the customer is able to inject chemicals at a very high rate with almost no added pressure drop from the tool.