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The Standard Flow System can be manually operated in most wells simply by holding the tubing by hand and oscillating it up and down in the well. Sometimes performance and endurance can be improved with the addition of a Lever Pump. 

The greatest performance improvements are realized with the use of the Hydrolift-2, PowerPack PP1 or PowerPump-2. The use of one of these automated actuators greatly improves the well development capacity of the inertial pump. The automated actuators are also recommended when substantial purge volumes are required.

The inertial pump has a substantial capacity for developing monitoring wells because of the cyclical action of the valve in the well screen area. This characteristic can be utilized to remove silt and sediment that has accumulated in the foot of the monitoring well and can also be used to remove fines from the sand pack and well screen.

The well development capacity of the Standard Flow D-25 foot valve can be enhanced by installing a SBD-25 Surge Block to the D-25 foot valve.

A Surge Block is an excellent well development tool. It simply press fits over the body of the Standard Flow or High Flow foot valve (D-25 or D-32).

The Surge Block effectively increases the outside diameter of the D-25 or D-32 foot valve to 1 7/8” In 2” wells and 3 7/8” OD in 4” wells, reducing the annular gap between the valve and the inside of the well screen to approximately 1/16” . This results in a significant increase in the surging action of the valve.

The use of the Inertial Pump and Surge Block together is one of the most effective methods for developing monitoring wells because it simultaneously surges and pumps the well. This frees up silt and sediment in the sand pack and screen and breaks down bridging, drawing these particles it into the well and then removes this material from the well.

The recommended method for developing a monitoring well with the inertial pump and Surge Block is to begin the development process with the Surge Block near the top of the well screen. Operate the pump with the Surge Block in this position until the turbidity level of the water being delivered from the pump decreases to an acceptable level. Once this level is reached then the Surge Block is lowered in the well screen one to two feet and the process is repeated. Developing wells in this manner is one of the best methods, often resulting in turbidity levels below 10 NTUs.

Factors that affect flow rate include such parameters as the depth of submergence of the foot valve, tubing diameter, well casing diameter, the length of pump stroke and the speed of oscillation of the pump.

Obviously, the speed of oscillation is the primary factor in imparting momentum to the water column in the pump's tubing. Generally a pumping rate of 100 to 180 strokes per minute is recommended. The recommended stroke length is 4 to 6 inches, with a longer stroke performing better in deeper piezometers.

Greater submergence of the foot valve increases the pressure differential (the pressure difference between the water within the tubing and the head pressure outside the valve) that is created at the end of the upward pump stroke. Increasing the pressure differential increases the rate of water inflow through the valve at the end of the upward stroke, thereby increasing the flow rate.

Another factor affecting the flow rate with the inertial pump is size of the annular gap between the inertial pump tubing and the ID of the well casing. When the inertial pump is operating, the flexible tubing will tend to wobble from side to side within the well casing. This wobble results in some of the up and down movement applied at surface to the tubing not reaching the depth where the valve is located. For this reason, the stiffer High Density Polyethylene tubing is usually preferred in deeper monitoring wells (depth in excess of 60 – 70 feet). The inertial pump performs best in smaller diameter piezometers (4" or less).