Bulk tank selection and isolation valve panels, repeated depot by depot

The requirement

Loading pumps at a fuel depot are fed from bulk tanks through three-port selection valves, which choose the tank, and two-port isolation valves. The integrator's control philosophy asked for a panel to drive them all: a tank selection can only change with every isolation valve closed, limit switch feedback lights the door and the site's traffic lights, and volt-free permissives inhibit the depot's existing pump panel.

The constraints

• The interlocks are the point of the panel: no selection change with any isolation valve open, with every valve position confirmed by its limit switches.
• The valves are in the depot's hazardous area. An ATEX version of the valve actuator the integrator wanted was proving hard to get, so closing the valves on a mains failure had to come from the panel.
• An emergency stop, with connections for remote stops, that closes every valve.
• A scope that grew during design, from four products to five.

What we built

A steel panel built around a Schneider PLC: the integrator was open to a basic PLC for the flexibility, and chose the Schneider controller over the Siemens LOGO! we had offered. The door is laid out in plates, one per valve, with closed and open lamps and a close/open switch, plus bulk tank select switches and power on, emergency stop active and battery fault lamps. A DIN-rail UPS with battery backup keeps the controls and valve supplies up long enough to drive the valves closed if the mains fails. Limit switch inputs, traffic light outputs and volt-free permissives to the pump panel are all on labelled terminals.

Delivery

The first panel was ordered in May 2024 and despatched at the end of July. The second followed in August with one change, a mains loss input to the PLC: in the integrator's words, "I need to place an order for another one of these panel please, with just one modification." A third went in October 2024, a fourth in September 2025, and a fifth in November 2025, simplified to five isolation valves with no tank selection for a depot that needed only that.

The outcome

One design, drawn once and adapted per depot, that the integrator orders when the next site comes up. Each one leaves Stoke-on-Trent with its own drawing and test certificate.