Sealing Valves
Sealing Valves
(OP)
I've recently started a job designing valves. I've been presented with a problem which I'm sure is very common. We have a meter with a housing and a flat top cover. The cavity the cover covers is about a trapezoid of about 6" x 10" x 4". Both parts are cast and to be machined later. 8 Bolts hold the 2 together.
This valve is to work at municipal water supplies up to 16 Bar.
I've been asked to look at a way of sealing the housing and top cover. We have 2 main options;
Cutting a groove in the cover to house an 'o' ring,
Using a gasket between the 2.
There are concernes that a rubber gasket could burst under peak pressure. Is there any benefit using a composite gasket?
I'm new to this field and would like any input on other methods that could be employed for sealing this assembly. Unfortunately I only have a day to try to find something before we take a punt with the rubber gasket design.
Thanks for your help.
Hayden
This valve is to work at municipal water supplies up to 16 Bar.
I've been asked to look at a way of sealing the housing and top cover. We have 2 main options;
Cutting a groove in the cover to house an 'o' ring,
Using a gasket between the 2.
There are concernes that a rubber gasket could burst under peak pressure. Is there any benefit using a composite gasket?
I'm new to this field and would like any input on other methods that could be employed for sealing this assembly. Unfortunately I only have a day to try to find something before we take a punt with the rubber gasket design.
Thanks for your help.
Hayden





RE: Sealing Valves
Given your geometry and depending on your bolting pattern, a preliminary o-ring groove could be cut 1/8 inch inside the perimeter of your "trapazoid" cover, just inside the bolting perimeter. Containment pressure is low, therefore select a Class 100 elastomer, 0.103 cross section with an inner diameter near 7.237 inches; this is #168 on the commercial available Parker-Hannifin scale. The geometry of your groove should be such that the ID of the path corresponds within 1/2% o-ring stretch. Gland depth should be 0.074/0.080 inches, thus providing 25% squeeze upon make-up with the cover.
I suggest using a generous fillet along the path of the o-ring groove, maybe 1/4 R or so. This will help in keeping the elastomer in the recess as the cover is flipped to be bolted in place.
Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada
RE: Sealing Valves