Cla-Val 92-01 Combination Pressure Reducing and Sustaining Valve

Two pressure duties from one hydraulic valve

The Cla-Val 92-01 performs two independent functions automatically. It keeps the downstream pressure constant despite fluctuating demand, and it sustains the upstream pressure at a pre-set minimum. The pressure reducing control responds to slight variations downstream and repositions the main valve at once; the pressure sustaining control is held open by upstream pressure and only modulates if that pressure falls to its set point.

That combination suits a low zone fed from a high-pressure main. The low zone gets a stable supply, and the main is protected against being drawn down when demand in the low zone peaks. Operation is fully hydraulic, with drip-tight seating and no external power.

Technical specifications

Pilot system and options

The schematic lists a Hytrol main valve, an X44A strainer and orifice, a CRD pressure-reducing control, a CRL or CRL-60 pressure relief control used as the sustaining pilot, and a CV flow control for the opening speed. Optional features are an X46A strainer, CK2 isolation valves, a CV closing speed control, check valves with isolation valves, remote pilot sensing, an X141 gauge and an X101D valve position indicator. The closing speed control should always be open at least three turns off its seat.

If a check feature is added and a pressure reversal occurs, downstream pressure enters the cover chamber and the valve closes, which prevents return flow into the main. The pilot adjustment ranges are specified at order together with the valve size, pattern, pressure class, trim material and end connection.

Where the 92-01 fits in a network

The datasheet application drawing shows a 92-01 between a high-pressure main and a distribution zone, with an X43H strainer and isolation valves at the inlet. It is the usual answer where a booster-fed or gravity system must not lose the pressure of the upper zone when the lower zone draws heavily.

Suggested maximum flow follows the 100-01 body: 210 gpm at 2 in, 460 gpm at 3 in, 800 gpm at 4 in, 1,800 gpm at 6 in, 3,100 gpm at 8 in and 7,000 gpm at 12 in, with intermittent values higher. Because the reducing and sustaining set points interact, supply both settings and the flow range when asking for a selection.

How the Cla-Val 92-01 valve works

The main valve is a diaphragm valve moved by line pressure through two pilots. The reducing pilot watches the downstream pressure and moves the main valve to hold it steady. The sustaining pilot watches the upstream pressure. It stays open while the upstream pressure is above its setting, and it only closes the main valve down if the upstream pressure falls to that setting. In this way one valve does both jobs without outside power.

Where the 92-01 is used

• Low zones fed from a high pressure main
• Water distribution networks
• Plants with large demand swings in one zone
• Lines where the main must not be drawn down
• Pump discharge headers

Selection checklist for the 92-01

• Valve size from 25 to 900 mm
• Globe or angle pattern
• Body material and flange class
• Inlet pressure and the downstream setting
• Sustaining pressure setting
• Flow range of the zone
• Strainer and isolation valves
• Closing speed control and gauges

Installation, commissioning and maintenance notes for the 92-01

Install the valve in a straight run with space to service the cover. Fit isolation valves and a strainer ahead of the pilots. Set the reducing pilot to the downstream pressure needed and the sustaining pilot to the minimum upstream pressure. Open the closing speed control at least three turns. Check the strainer and the diaphragm at planned intervals.

Requesting a quotation for the Cla-Val 92-01

Please send the size, the end connection, the pressure settings and the quantity. Seven Star LLC serves industrial customers in Oman and the GCC and replies with a quotation based on the information provided.

92-01 valve sizes

The Hytrol main valve is offered from 25 to 900 mm, in globe or angle patterns.

92-01 body materials

The body and cover are ductile iron for sizes 1 to 36 inch. Cast steel or bronze is offered for 1 to 16 inch.

92-01 pressure ratings

On 150 class flanges the ratings are 250 psi for iron, 285 psi for steel and 225 psi for bronze. On 300 class, grooved and threaded ends the rating is 400 psi.

92-01 pilot controls

The CRD pilot reduces pressure, and a CRL or CRL-60 relief pilot serves as the sustaining control.

92-01 optional features

The options are an X46A strainer, CK2 isolation valves, closing speed control, check valves, remote sensing, an X141 gauge and an X101D position indicator.

92-01 temperature limit

The standard pilot system suits water up to 180 degrees F.

92-01 flow guide

The suggested continuous flow is 55 gpm for 1 inch, 300 gpm for 2-1/2 inch and 4,900 gpm for 10 inch.

92-01 weight

The weight runs from about 15 lb for 1 inch to 3,900 lb for 20 inch.

Valve records for the 92-01

Record the size, the pilot settings and the dates of strainer cleaning.

Choosing the right 92-01 settings

Set the sustaining pressure above the lowest pressure that the main can safely carry.

Documents and quotation

The engineering data sheet E-92-01 is attached, with dimensions in inches and millimetres. Before ordering, confirm the pattern, end connection, pressure class, both pressure set points and any check feature. For a reducing-only duty see the Cla-Val 90-01, and for a reducing valve with surge relief see the 94-01, both listed under Control Valves.