Cla-Val 94-01 Pressure Reducing and Surge Control Valve

Pressure reduction with a fast surge pilot

The Cla-Val 94-01 adds a second pilot to the standard pressure reducing valve. The CRD pilot reduces a higher inlet pressure to a steady lower downstream pressure, while a CRL-60 surge pilot opens quickly if the downstream pressure rises rapidly above the reducing setting. That quick relief stops a pressure spike from travelling into downstream zones.

It is built on the Hytrol 100-01 with an X58C restriction assembly, and it keeps the benefits of the 90-01 family: accurate control, easy adjustment and a fully supported frictionless diaphragm. A check feature is optional.

Technical specifications

Where surges come from and how the 94-01 answers them

The datasheet application is a reduced-pressure station feeding several downstream zones through on-off remote control valves. When one zone valve closes quickly, the others can see a pressure rise before the reducing pilot reacts. The surge pilot is set about 10 psi above the pressure-reducing control so that it only operates when a true surge occurs and normal regulation is left to the CRD.

If the check feature is fitted and pressure reverses, downstream pressure enters the main valve cover chamber and closes the valve to prevent return flow. The valve opens and closes in response to the pilots alone, with no actuator or external power source, so the same arrangement works on remote sites where only line pressure is available.

Pilot ranges and ordering information

Both pilots are specified by adjustment range. The CRD options are 2 to 30, 15 to 75, 20 to 105 and 30 to 300 psi; the CRL-60 options are 0 to 75, 20 to 105, 20 to 200 and 100 to 300 psi. The 30 to 300 psi CRD range and the 20 to 105 psi CRL-60 range are supplied unless otherwise specified, and remote sensing is available. Standard pilot materials are low-lead bronze with brass and stainless steel trim and Buna-N rubber, with stainless steel or Monel optional.

Optional accessories mirror the other 90-series valves: X46A strainer, CK2 isolation valves, closing and opening speed controls, check valves, X141 gauge, X101 position indicator and X43 Y-strainer. Specify the catalogue number 94-01, size, pattern, pressure class, end connection, trim, both adjustment ranges, options and whether the valve is vertical.

How the Cla-Val 94-01 valve works

The main valve is a diaphragm valve that opens and closes with the pressure in its cover chamber. The CRD pilot senses the downstream pressure and lets the main valve throttle so that the downstream pressure holds at the set value. The CRL-60 surge pilot sits in the same circuit. If the downstream pressure rises fast above the setting, the surge pilot opens quickly and relieves the rise before it moves on into the pipe network.

Where the 94-01 is used

• Pressure reducing stations that feed several zones
• Lines with quick closing remote control valves
• Water supply and distribution mains
• Plant water systems with sudden demand changes
• Stations that need protection from pressure spikes

Selection checklist for the 94-01

• Valve size from 25 to 900 mm
• Globe or angle pattern
• Threaded, flanged or grooved ends
• Body material: ductile iron, cast steel or bronze
• Pressure class of the flanges
• Inlet pressure and downstream setting
• CRD and CRL-60 spring ranges
• Optional check feature

Installation, commissioning and maintenance notes for the 94-01

Install the valve with room around the cover for service. Fit isolating valves and a strainer ahead of it. Set the CRD pilot to the downstream pressure needed. Then set the surge pilot about 10 psi above that value, so it acts only on a real surge. Open the pilot circuit bleeds to remove air on start-up and inspect the diaphragm at planned intervals.

Requesting a quotation for the Cla-Val 94-01

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.

94-01 valve sizes

The sizes run from 25 to 900 mm in globe or angle patterns.

94-01 body materials

The body and cover are ductile iron, cast steel or bronze. Bronze is offered up to 16 inch.

94-01 pressure ratings

The recommended maximum is 250 psi for iron, 285 psi for steel and 225 psi for bronze on 150 class flanges.

94-01 pressure reducing pilot

The CRD pilot has spring ranges of 2 to 30, 15 to 75, 20 to 105 and 30 to 300 psi.

94-01 surge pilot

The CRL-60 pilot has ranges of 0 to 75, 20 to 105, 20 to 200 and 100 to 300 psi.

94-01 temperature limit

The temperature limit for water is 180 degrees F.

94-01 flow guide

The suggested continuous flow is 125 gpm for 1-1/2 inch, 800 gpm for 4 inch and 3,100 gpm for 8 inch.

94-01 weight

The weight runs from about 50 lb for the 2-1/2 inch to 6,200 lb for the 24 inch.

Valve records for the 94-01

Record the size, the pilot ranges and the settings made at start-up.

Choosing the right 94-01 pilot range

Choose the CRD range so the set pressure sits near the middle of the spring range.

Documents and quotation

The data sheet E-94-01 is attached to this page and includes dimensions, weights and the valve selection chart. Provide the inlet pressure range, the downstream set point, the surge set point and the flow range with the RFQ. More Cla-Val pressure control valves are listed under Control Valves.