Batescrew Non-Return
In-Line Valves 
                              
click here for  Dimensions

These are supplied with flanges, as seen here or with plain ends, for welding directly into a pipeline. Inlets and outlets of mixed sizes may be specified.

In using this type of valve, careful consideration should be given to the possibility of water-hammer damage to other parts of a reticulation system.  It may be necessary to install some form of pressure limiting device, see below.

PRESSURE SURGE PROTECTION
Surges of extreme severity can be generated when a large mass of moving water is brought to a sudden stop by a valve.  This can happen even though the column of water may have moved only a short distance, such as occurs at the shutting down of a pump, when flow is reversed and movement occurs while a flap valve is closing.  The resulting water-hammer impact may be severe enough, depending on mass and velocity, to severely damage pipes or fittings.
A rough ‘rule of thumb,’ used for many years, suggests that a momentary pressure surge of this nature might be in the order of ten times the normal static head of the system.
Simple precautions can be taken to keep pressure surges within acceptable limits. Relief valves, surge towers and vent pipes, are common examples.
It is strongly recommended that in-line valves be provided with some form of pressure relief, unless it is definitely known that this is not warranted in the particular instance.

Relief Valves.  These range from very simple spring loaded devices, to sophisticated industrial models, with features such as chatter-free rapid opening with slow closing;  accuracy and long term stability of the control setting;  opening to full capacity on minimum pressure rise, etc. etc.  Batescrew can assist with selection of a suitable fitting for a proposed application.
Relief valves fitted to our in-line n-r valves, for irrigation purposes, are usually 150mm diameter, with a Table D flange.  Provision of a matching branch pipe on the valve body needs to be specified when ordering.

OPTIONS available with IN-LINE VALVES.  (indicate when ordering)
1)  Drainage Bypass, typically a 50mm steel line with stop cock, to allow controlled drainage past a closed flap.
2)  Branch Pipe for pressure relief valve.  This is usually a 150mm diameter pipe, with a Table D flange.  Alternate positions for branch pipes are indicated on the dimension sheet below.
3)  Flanges.
   Prices do not include flanges or optional fittings, which are customer specified.

DIMENSIONS
Nominal Diameter and Valve Dimensions (mm)

 

300

350

375

400

450

500

525

600

675

750

900

1050

1200

1350

1500

1650

1800

A

455

525

550

580

640

705

735

825

825

995

1175

1355

1490

1490

1700

1910

2110

B

12

12

12

16

16

16

16

20

20

20

20

25

25

25

25

25

25

H

715

766

791

816

887

938

963

1040

1116

1192

1364

1517

1669

1822

1974

2126

2279

P

406

470

495

521

584

641

673

756

756

927

1092

1251

1410

1410

1615

1825

2019

Q

12

12

12

12

12

16

16

16

16

20

24

28

32

32

36

40

44

R

M20

M20

M20

M20

M20

M20

M20

M20

M20

M20

M25

M25

M25

M25

M25

M25

M25

S1

317

368

393

418

469

520

545

622

698

774

926

1079

1231

1384

1536

1688

1841

S2

317

368

393

418

469

520

545

622

698

774

926

1079

1231

1384

1536

1688

1841

T

6

6

6

6

6

6

6

6

6

6

6

6

6

6

6

6

6

W1

100

100

100

100

100

100

100

100

100

100

100

100

100

100

100

100

100

W2

100

100

100

100

100

100

100

100

100

100

100

100

100

100

100

100

100

X

339

364

377

389

415

440

493

531

569

607

723

800

876

952

1028

1104

1181