A computer-implemented system for designing a pressure-dosed drain field, wherein a user uses the system to design a pressure-dosed drain field, comprising:
- (a) a screen that allows a user to specify length and diameter for pipes that comprise the forcemain and discharge assembly of a pressure-dosed drain field;
- (b) a minor loss screen that calculates minor losses for a pressure-dosed drain field based on fitting selections made by the user;
- (c) a screen that allows the user to specify pumping liquid level and discharge elevation for a pressure-dosed drain field;
- (d) wherein the drain field designed by the user will have a plurality of laterals, wherein the plurality of laterals comprises a first lateral, and wherein the first lateral comprises a distal orifice, a screen that allows the user to select a number of laterals and enter a specified residual pressure for the distal orifice of the first lateral;
- (e) a screen that allows the user to enter or select a coefficient to be used in calculating friction losses in the laterals, manifold, forcemain and pump discharge assembly of a pressure-dosed drain field;
- (f) wherein the manifold comprises segments, wherein the number of manifold segments is determined by the number of laterals entered by the user, wherein each segment has a diameter and length, wherein the laterals are spaced a certain distance apart from one another, and wherein the spacing between manifold segments determines the spacing between the laterals, a screen that allows the user to enter the diameter and length of each manifold segment;
- (g) a pump file that comprises a list of pumps for a pressure-dosed drain field and a window that displays a list of the pumps in the pump file;
- (h) wherein each lateral comprises a plurality of orifices, wherein the space between each orifice on a given lateral defines a lateral segment, wherein each lateral segment has a diameter and length, and wherein each lateral has an elevation, a grid that indicates, for each lateral, orifice diameter, orifice spacing, diameter and length of each lateral segment, and the elevation of the lateral, wherein each of the values displayed in the grid is modifiable by the user;
- and
- (i) a tabulated results screen that shows, for each lateral, maximum and minimum orifice flow rate, orifice flow differential, lateral flow rate, total lateral head loss, manifold flow rate, manifold head loss, and pressure at the distal orifice of each lateral;
- wherein the system automatically calculates flow differential across the pressure-dosed drain field designed by the user and displays the flow differential on the tabulated results screen;
- wherein the calculation of flow differential across the pressure-dosed drain field is accomplished by:
- (1) calculating an orifice flow in response to a specified residual pressure for a distal orifice on a first lateral;
- wherein there is a first lateral segment between the distal orifice and a second orifice, (2) calculating a segment flow for the first lateral segment, which equals the flow from the distal orifice;
- (3) calculating pressure at the second orifice by summing the specified residual pressure at the distal orifice and pressure loss in the first lateral segment;
- (4) calculating flow at the second orifice;
- (5) calculating flow for subsequent lateral segments by summing the flows from prior orifices;
- (6) calculating pressure at subsequent orifices by summing the specified residual pressure at the distal orifice and pressure losses in all lateral segments between the subsequent orifice and the distal orifice;
- continuing the calculations (6) for subsequent lateral segments until pressure and flow values are generated for the entire length of the lateral;
- (7) calculating a percentage increase in flow from one orifice to the next on a given lateral;
- based on information specified by the user as to manifold segment length and diameter, (8) calculating pressure loss in the manifold and determining manifold pressure at the beginning of a second lateral;
- wherein the second lateral has a distal orifice, assuming that pressure at the distal orifice on the second lateral is the same as the residual pressure on the first lateral, (9) calculating pressure back to the beginning of the second lateral;
- if the calculated pressure at the beginning of the second lateral using a value as a starting point for pressure at the distal orifice on the second lateral is not within a specified range of the pressure at the beginning of the second lateral calculated by using the same value as a starting point for the residual pressure on the first lateral, (10) adjusting pressure at the distal orifice of the second lateral until the calculated pressure at the beginning of the second lateral based on the pressure at the distal orifice of the second lateral is within a specified range of the calculated pressure at the beginning of the second lateral based on the pressure at the distal orifice of the first lateral;
- wherein there is a manifold segment between the second lateral and a third lateral, (11) taking the pressure at the beginning of the second lateral and calculating pressure at the beginning of the third lateral, taking into account head loss for the manifold segment between the second and third laterals;
- wherein the third lateral has a distal orifice, assuming that pressure at the distal orifice on the third lateral is the same as the residual pressure on the first lateral, (12) calculating pressure back to the beginning of the third lateral;
- if the calculated pressure at the beginning of the third lateral using a value as a starting point for pressure at the distal orifice on the third lateral is not within a specified range of the pressure at the beginning of the third lateral calculated by using the same value as a starting point for the residual pressure on the second lateral, (13) adjusting pressure at the distal orifice of the third lateral until the calculated pressure at the beginning of the third lateral based on the pressure at the distal orifice of the third lateral is within a specified range of the calculated pressure at the beginning of the third lateral based on the pressure at the distal orifice of the second lateral;
- continuing the calculations (7)-(13) for all laterals until a pressure has been calculated at the beginning of each lateral in the drain field;
- taking head loss into consideration, calculating pressures for the forecemain and discharge assembly;
- and
- wherein the drain field has a minimum flow rate orifice and a maximum flow rate orifice, calculating a flow differential across the drain field, wherein the flow differential across the drain field is the difference in flow rates between the minimum flow rate orifice and the maximum flow rate orifice.