Characteristics Of Gate Valve

CHARACTERISTICS OF GATE VALVE AIM:To determine the constant ‘K’ for the gate valve in different positions and compare it with the literature values. APPARATUS:Gate valve (dia: - 1”), differential manometer (range: - ± 50 cm, least count: 1 mm), water tank (base dimensions: - 2.44 m × 0.94 m), stop watch THEORY : Valves are required to be introduced in the pipelines for one or the following purposes. 1. To stop the flow of liquid altogether. 2. To regulate rate of flow of the liquid. 3. To regulate the pressure or head in the pipelines. Following is one of the basic two types of the valves to be studied. Gate valve: This is very commonly used valve, in which moving element has the form of a disc or circular gate, wedge-shaped in cross-section, having a nut which engage with the thread of the operating spindle. In the fully open position, the gate is withdrawn clear of the waterway and hence this valve is designated as full-way valve. PROCEDURE: 1. First the gate valve is kept in full open position. 2. The inlet valve is opened & flow is started. 3. Manometer reading is taken. 4. The discharge is calculated by noting the time for 5 cm rise of water in tank. 5. Keeping the valve half open & quarter open repeat same procedure.

OBSERVATIONS: TABLE 1: Valve position Full open

Half open

Quarter open

Sr.

∆ h (cm of Hg) Time (sec)

hf (cm)

no. 1. 2. 3. 4. 5. 1. 2. 3. 4. 5. 1. 2. 3. 4. 5.

[manometer]

[ h * (SHg – Sw) ]

CALCULATIONS :

TABLE: 2 Valve

Sr.

Qact (m3/sec)

V (m/s)

K

position

no.

Q = (Atank * h) / t

V = Q / Apipe

K = 2 g hf / v2

Full open

1. 2. 3. 4. 5.

Half open

1. 2. 3. 4. 5. 1. 2. 3. 4. 5.

Quarter open

CONCLUSION: