non-return valves Archives - Waverley Brownall

Find below the flow rate chart for Non-Return valves manufactured in stainless steel.

Valves are available with working pressures up to 3000 psi and can be supplied to comply with NACE specification.

Pressure drop in PSI

10	20	30	40	50	60	70	80	90	100	110	120	130	140	150

Gallons per minute

CV1 (1/8″)	1.94	3.10	3.91	4.59	5.02	5.44	5.66	6.06	6.36	6.67	6.97	7.27	7.50	7.75
CV2 (I/4″)	2.02	2.85	3.46	4.00	4.43	4.86	5.27	5.65	6.02	6.36	6.93	7.25	7.52	7.78
CV3 (3/8″)	1.60	5.04	6.14	6.77	7.65	8.38	9.03	9.71	10.30	10.50	10.80	11.0	11.10	11.30
CV 4 (1/2″)	7.15	9.94	11.90	13.70	14.80	16.0	16.90	17.60	18.90	19.90	20.80	21.30	22.40	23.20
CV6 (3/4″)	4.30	9.50	32.30	37.50	42.80	47.10	51.0	54.7	58.3	61.5	64.8	67.4	70.5	73.2
CV8 (1″)	4.0	9.90	35.7	41.5	46.9	51.6	55.7	59.6	63.5	67.2	70.1	72.9	75.8	78.4

Numbers represented, please note numbers 37.7 is representative of 37.70. Examples: 55.7 = 55.70, 59.6 = 59.60 and so forth. For quick reference only.

Non-Return Valve specification

Parts list and breakdown, including an inlet at the base following from PART F upward to PART A to an outlet.

PART A – Valve Body
PART B – Spring
PART C – Piston
PART D – Piston Seal
PART E – Body Seal
PART F – Valve Seat

Seal Type

P.T.F.E Seals are supplied as standard unless use of Viton seals are necessary.

The use of P.T.F.E seals with non-return valves up to 3/8″ containing a low pressure spring such as 2-5psi, combined with low back pressure, can lead to difficulty in forming a leak-tight seal between the piston seal and the cone seat. This is overcome by using either a Viton seal or a stronger spring. Valve opening pressures of 35 psi are available up to 1/2″, with 2-5 psi only available for 3/4″ and upward.

Seal Kits

Replacement seal kits are available and consist of the following items; piston seal, body seal and spring.

Replacement seal kit part numbers for immediate order:

Valve Size	Part Number
1/4″	CV2 SEALS
3/8″	CV3 SEALS
1/2″	CV4 SEALS
3/4″	CV6 SEALS
1″	CV8 SEALS

In Line Filters

A filter should always be placed upstream of the non-return valve when the media has solids suspended in it. If a filter is not used the piston seal may become damaged, so allowing the media to flow back upstream.

Information supplied via WAVERLEY® Components and Products Limited Ltd. Product Catalogue ‘316 Stainless Steel Pipeline Components and Valves’ and is not to be redistributed, copied or shared without a link to the original source under any circumstances.

Information supplied is for reference use only.

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mini check valve sectioned stainless steel

(Pictured) Miniature Check Valve

Cracking pressure is the inlet pressure at which the first sign of flow occurs. Although often used with liquids, check valves are also used in industrial processes which handle gases and chemicals. Back pressure refers to the difference in pressure between the inlet and the outlet of the valve. When the cracking pressure is reached, the valve will open to allow flow of the material, when it drops, the valve will close.

*Adjustable springs allow for a variety of cracking pressures.

(PSI)
Miniature check valve cracking pressure – 3, 5, 10, 20, 40, 60, 100, 150
Standard check valve cracking pressure – 5, 15, 25, 30, 45

What is a check valve?

A check valve, is a type of valve used in areas of instrumentation tubing or pipeline to control the flow of a gas or liquid. It allows the inner material to flow through a single direction (unidirectional) with minimal pressure drop.

Also known as a non-return valve or two-port valves, they come in many different forms. Examples of this include ball check, stop-check and lift-check valves. Pneumatic non-return valves will be used when a check valve is insufficient, Eg. where there is a risk of chemical spillage or excessive flooding.

Our check valves consist of a main body, spring, poppet, O-ring, body seal and end cap.

Working Pressures

Waverley Brownall check valves are tested for sealing performance based on BS 6755 Pt.1. The tests consist of both low and high pressure shell for up to 4,500 psi, the equivalent of 310 Bar. Miniature check valves feature a working pressure of up to 6000 psi with a cracking pressure from 3 to 350 psi. A minimal pressure drop and bubble-tight shut off are included in both check valve series.

Our check valves are available in sizes from 1/4″ up to 1″ in stainless steel, with a working pressure of up to 3000 psi. This is the equivalent to 206.8427 bar. Optional end connections for thread forms include NPT (National Pipe Taper), BSPT and BSP.

Tables showing pressure drop (psi) vs flow (SCFM) for air flow vs. water can be found in our precision valves catalogue. Sizes tested include 1/4″, 3/8″, 1/2″ and 1″. The O-ring is in material PFTE/Viton with varying temperature range capability. A nominal cracking pressure of 5, 15, 25, 30 and 45 psi with others on request.

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