Enclosure Design of smart meter for remote controlling of valves

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Requirements :

The Requirement was to Design an Enclosure which will house a PCB with the battery and 4 different Valves with different mounting holes will be mounted below the enclosure based on the application of the user. We had to provide knockouts for different holes with the valve numbers engraved so that the installation person can easily recognize the point where he needs to make a drill. The holes are further provided with projections so that when the valves are assembled, the resin will be poured on the mounting locations for the proper sealing of the holes. The device will be used directly on the valve or will be used to mount on the valve when it is used as emitter. So, we had to provide wall mounting option as well.

The Client designs two products having the same electronic board: The Smart-Valve and the Smart Emitter. The Strega SV (Smart Valve) and SE (Smart Emitter) products are IoT products that use the Lora radio system. Their main use is the solenoid valve control. The SV is in the form of an all-in-one valve, that is to say that the box containing the electronics is attached directly to the valve mechanics (see photo below).

2 The enclosure (housing) The current enclosure used in the production if of brand BOPLA ref: 03219000, in ABS, dimensions are 160 x 80 x 60 mm. While the current length is OK with the existing BOPLA, the width tolerance of the lid is a bit too tight and we currently need to do some extra manufacturing removing few 1/10mm to get the lid close more easily onto the battery holder. Current bottom box is 40 mm height, lid is 20 mm height (=60 mm total).

The bottom of the box is currently of 3mm. For the new custom housing, we need to keep this thickness.

Below and example mounted on a XXXXX size valve:

After drilling holes 1,2,3, the housing can be assembled on the valve. For each valve dimension, the positions of screws 1 and 2 are different (dimensions provided later), screw 3 remains the same and fixed. On the new custom housing, it will be asked to provide around the 1,2,3 screws a kind of “chimney” a few millimeters high to be able to contain the sealing resin applied on the screws more easily.

New Housing Requirement:

The specifications of the new housing, in addition to those indicated previously are: – White colour (the SE/SV can be placed outdoor) – Type of plastic material: ABS as currently, or other according to your advice, however, care must be taken not to degrade the level of radio transmission. – Dimensions: close to current ones (or smaller if possible?) – On the lid, it is necessary to envisage a zone to put any logo (ours or that of a client) by either printing or engraving, depending on the cost. The goal being to delete the use of a sticker as it is currently done (see below). Engraving the Company logo on a little square and flat surface of the lid would permit to apply, when required, a customer’s logo sticker that would then hide ours. – IP protection level: IP66/67: special care must be proposed on the sealing as we are not satisfied from IP rating achievement of current BOPLA box. – Optimization of the attachment of the electronic card: Currently 4 screws M3 are used, if possible, improve this point, with a solution like clips, or with the use of 2 studs and 2 screws diagonally. To see according to your proposals. – Provide a system for fixing the housing on wall of on mast (tube), using zip ties or other. – Define on the perimeter of the electronic card, borders to contain a potting resin. Details to come.

Our Concept Sketches

Finalized Concept:

The Blue and Orange surfaces indicate matt and glossy finish.

3D Printing :

Low Volume Production to test the product :

The customer wanted few boxes to test them in field for the functionality and end user feedback before investing in injection molding. So we manufactured them using silicon molding since it is best suited when the volume required is 20-50 units.

Injection Molding :

The Top and Bottom cover were done using family mold since the material and color were same. The Mount and Gasket were done in separate Molds. The Logo engraving was done using insert so that if the customer wants to engraving his different logo, we can change the insert alone keeping the mold intact.

Now we supply 5000 boxes on monthly basis based on his logo and color preference.