BS 5150 Non-Rising Stem Metal Seated Gate Valve

Design Characteristics & Advantages

The product photo & technical drawing of BS 5150 non-rising stem (NRS) metal seated gate valves, ductile iron, handwheel operated, Series No.: MTS-NV507.

SJZ Metalsin supplies BS 5150 non-rising stem (NRS) metal seated gate valves, made from grey cast iron or ductile iron. The valves shall be furnished with flanged ends, the drilling dimensions of which shall be in accordance with BS 4504 3.2 or BS 1560 3.2. This MTS-NV507 series gate valve features its non-rising stem and hollow wedge design. In contrast to the fixed-gate stem (rising stem), the valve stem is threaded to the wedged gate in the non-rising stem design. Turning the handwheel threads the stem into the gate, causing the gate to move upwards and lift out of the flow stream. The non-rising stem design is a specific type of valve operation mechanism where the stem does not extend above the valve bonnet (the top cover of the valve). This design is commonly used in applications where the stem extending above the bonnet would be a hindrance or a safety concern.

BS 5150 non-rising stem metal seated gate valves, 6″ PN16 RF flanged, made from QT450 ductile iron (ASTM A395 Gr. 65-45-15).

The wedge of the BS 5150 NRS metal seated gate valve has the hollow construction. There is a T-slot in the top of the wedge’s hollow interior, where the stem nut with trapezoidal threads are mounted. This stem nut forms a driving pair with the trapezoidal thread at the bottom end of the valve stem. The hollow wedge is furnished with guide slots on both sides of the non-sealing exterior surface, which match with guide ribs on the valve body to form a guiding mechanism. The central portion of the wedge is hollow, reducing the amount of material used, thereby reducing the overall weight, while still maintaining sufficient strength and stability. Copper alloy seat rings are inserted/ embedded respectively into the sealing areas of valve body and wedge gate to form a metal-to-metal seal. In non-rising stem wedge gate valves, the valve stem undergoes only rotational movement during valve opening or closing, without any vertical displacement. Therefore, the height dimension of the valve stem is relatively small, which is also advantageous for the sealing of the stem packing. To determine the open or closed position of the gate, an indicator can be used.

Valve Parts & Material Selection

As illustrated in the technical drawing, the main valve parts of BS 5150 metal-seated non-rising stem gate valves (MTS-NV507 series) include: (1) body; (2) seat rings; (3) wedge face rings; (4) wedge; (5) wedge nut; (6) stem; (7) body gasket; (8) bolts; (9) nuts; (10) bonnet; (11) gland follower bolts; (12) stuffing box gasket; (13) stuffing box; (14) packing; (15) gland follower; (16) packing gland; (17) handwheel; (18) identification plate; (19) washer; (20) handwheel nut; The specific material for each valve part is listed in the table below.

Dimensions

The main structural dimensions including face-to-face dimensions (L), maximum height (H), and diameter of the handwheel (Do) of BS 5150 flanged non-rising stem gate valves are presented in the tables below. According to BS 5150 & BS 2080, face-to-face dimensions (L) are available for pressures PN6, PN10, PN16, PN25, Class 125 and Class 150: (1) Valves of PN6 shall have L dimensions in accordance with basic series 14; (2) Valves of PN10, PN16, Class 125, Class 150 shall have the same L dimensions in accordance with basic series 3; (3) Valves of PN25 shall have L dimensions in accordance with basic series 14.