Tapflo T420 Metal Air-Operated Diaphragm Pump 2 Inch

A 2-inch metal AODD pump with up to 570 l/min of flow

The T420 is the 2 inch size in Tapflo's metal series of air-operated double diaphragm pumps, available in aluminium, cast iron, AISI 316 stainless steel or PTFE-coated aluminium. It delivers up to 570 l/min at an air pressure of up to 8 bar, passes solids up to 15 mm and needs no electricity, which makes it a common choice for workshop fluids, paints and inks, mining and construction sumps, ceramic slips and chemical transfer. Tapflo states that the design uses about 70 percent fewer parts than other brands, so maintenance is by simple diaphragm and ball replacement.

Technical specifications

Reading the pump code

The brochure prints the code as T, basic option letters, size, wetted metal and then diaphragm and ball materials. Options include B (backup diaphragm system), D (drum pump), F (filter press pump), L (valve lift), P (powder pump), T (twin in/outlet), X (ATEX group II category 2) and Z (ATEX category 1). The metal letter is A aluminium, C cast iron, S AISI 316 stainless steel or X PTFE-coated aluminium. Diaphragm letters include T PTFE, B PTFE TFM 1705B, E EPDM, N NBR, V FKM and W white EPDM, and ball letters include T PTFE, S AISI 316, E EPDM, N NBR, U polyurethane, K ceramic and V FKM.

Hazardous areas and installation

All aluminium and cast iron pumps are ATEX approved as standard TX models for Zone 1 (Ex II 2G Ex h IIC T6 to T4 Gb; Ex II 2D Ex h IIIC T60 to T125°C Db). Standard stainless steel pumps are not allowed in hazardous areas; conductive TX and TZ versions are offered for them, with TZ marked Ex II 1G Ex h IIC T6 to T4 Ga. The pump can be installed flooded, self-priming or submerged, with the exhaust piped away when submerged. It runs dry without damage, can work against a closed discharge valve, and the connections can be rotated through 180 degrees. Optional ball lifters (TL) and pneumatic drainage let the pump be emptied without disconnecting it.

Documents and quotation

The Tapflo diaphragm pump brochure is a 40-page document covering the metal, PE and PTFE, and sanitary series, with curves, dimensions and technical data. Send the fluid, temperature, viscosity, solids size, flow and head, and the zone if hazardous. See other pumps or the VERDERAIR VA50 for a comparable range.