Abstract: For use with a wetwell having a geometrically regular upper portion and a geometrically irregular lower portion, a method is provided for estimating the volume in the lower portion. Upper and intermediate level sensors are provided in the upper portion of the wetwell, and a lower level sensor is provided in the lower portion. The volume between the intermediate and upper levels is first calculated. Then, the wetwell performs a series of cycles, each allowing the wetwell to fill with liquid between the lower level sensor and the upper level sensor while the pumping means is off or at a low rate, then causing the wetwell to be emptied from the upper level to the lower level by running the pump. During the filling part of each cycle, the time required for liquid to rise between the lower level and the intermediate level is noted, as is the time required for the liquid to rise between the intermediate level and the upper level. If these times are T.sub.2 and T.sub.

Abstract: A method and apparatus for determining liquid flow through a system including a container from which liquid is pumped out by one or more pumps, the pumping rate for all combinations of pumps being known and stored in a memory. When pumping is off, the liquid surface rises from a lower to an upper limit level. When the surface reaches the upper limit level, the pumping phase begins. When the surface reaches the lower level, the pumping is stopped and the cycle is repeated. If only one pump is required, the inflow rates prior to and just after the pump cycle are averaged. This average flow rate is multiplied by the pump time and added to the totalizer. Then the container volume is also added, following which the outflow rate (pump rate) is calculated by using the previously established average inflow rate (total volume divided by pumptime plus the average inflow rate). This value can be stored in the addressable memory.

Abstract: A sewage pumping system includes a container, an inlet for the inflow of liquid and a modality for ascertaining the liquid level in the container. Two or more pumps are provided, each having an inlet communicating with a container and an outlet communicating with the common conduit. A pump controller receives information from the modality for ascertaining the liquid level and is adapted to start and stop individual pumps. A pressure sensing device is located in the conduit for sensing the backpressure against which pumps in operation are pumping, and for generating a second signal corresponding to the sensed backpressure, the signal going to the pump controller. An addressable memory is operatively connected with the pump controller and stores values corresponding to pumping rates vs. backpressure for each of the pumps, along with high and low backpressure values for each pump. On high backpressure the pump controller avoids pumpstarts which will not result in a net increase in the total pumping rate.

Abstract: A method and apparatus is provided for calculating the flow rate through a pumping station that has at least one pump. For each pump and for each combination of pumps on oscillator circuit is provided of which the output frequency can be adjusted. The frequency of each such circuit is adjusted to represent the pump rate for the pump or combination of pumps to which that oscillator circuit corresponds. While operating the pumping station, a totalizing device has fed to it the output frequency of that oscillator circuit which corresponds to the pump or combination of pumps which is operating at any given time, and the total in the totalizer is incremented by a given amount for each pulse encountered. Thus, the totalizer is continuously updated.

Abstract: A self-releasing lift hook includes a main cylinder with a main piston slidable in the cylinder and defining a main chamber above the piston and a main chamber below the piston. A hook is connected to one of the cylinder and the piston, and a lift ring is connected to the other. A coil spring biases the piston in a direction which causes the hook and the ring to approach each other, so that when a load is placed on the hook, the hook and ring move apart and cause energy to be stored in the spring. A main passage through the piston, incorporating a check valve, allows fluid to flow between the main chambers when the hook and ring are moving apart, but restrains such fluid flow when the hook and ring approach each other. A bleed passage is provided through the piston to allow slow transfer of fluid from one side to the other of the piston.

Abstract: A self-contained, submerged aparatus for monitoring the height of a liquid in a wetwell includes a tube defining an upright conduit, a first chamber at the bottom of the conduit and communicating with it, a second chamber adjacent the first chamber and separated from it by a first impervious non-rigid membrane, the second chamber being defined in part by a second impervious non-rigid membrane in contact with the liquid in the wetwell. The second chamber contains a first liquid to which the membranes are inert, and the first chamber contains a second liquid to which the first membrane is inert. Pressure from the liquid in the wetwell exerted against the first membrane is transmitted to the second membrane and causes the second liquid to rise in the tube. The top of the tube is vented to the atmosphere, and a plurality of electrical terminals disposed at spaced locations lengthwise of the tube are provided for producing a signal which is a function of the height of the second liquid in the conduit.

Abstract: For a pumping station having a pump, a method is provided for calculating the flow rate, which includes the storage in a computer memory of a table correlating pumping rate for the pump with the pressure differential across the pump. Data is detected from which the differential pressure across the pump can be computed, and then a computer is utilized firstly to compute the differential across the pump, then to access the table in the memory to determine the pumping rate corresponding with the computed pressure differential, then to calculate the volume pumped during the time interval, then updating a totalizer in the memory by adding in the calculated volume.

Abstract: There is provided a method of determining the total inflow of a liquid through a liquid-flow system such as a sewage pumping station, in which liquid enters a sump cavity and is pumped out of the sump cavity on a periodic basis. The probable inflow rate during each pumping cycle is derived by first determining the true inflow rate prior to the beginning of a pumping cycle and extrapolating its trend forward through the time of the pumping cycle to arrive at a first calculated inflow rate, then determining the true inflow rate after the end of a pumping cycle and extrapolating its trend backward through the time of the pumping cycle to arrive at a second calculated inflow rate, and averaging the first and second calculated inflow rates to obtain the probable inflow rate during the pumping cycle. This latter rate is then multiplied by the time during which pumping takes place to yield an inflow during pumping, and this amount is added to the sump volume for each complete cycle.

Abstract: There is provided a method of determining the total inflow of a liquid through a liquid-flow system in which the liquid enters a sump cavity and is pumped out of the sump cavity by pump means. Computing means calculates an on-going total inflow volume for the liquid by (i) adding in the sump cavity volume between a lower and upper limit level each time the liquid surface rises to the upper limit level, and (ii) determining the inflow rate over the last portion of the filling time just described and extrapolating this inflow rate over the time when the pump means is pumping to yield an incremental quantity, such quantity being added in to the on-going total inflow volume.